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PLOS One logoLink to PLOS One
. 2021 Jun 24;16(6):e0253753. doi: 10.1371/journal.pone.0253753

The effect of mental health on sleep quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study

Leiyu Yue 1,#, Rui Zhao 2,#, Qingqing Xiao 1,#, Yu Zhuo 1,#, Jianying Yu 1,#, Xiandong Meng 1,*,#
Editor: Stephan Doering3
PMCID: PMC8224907  PMID: 34166474

Abstract

Background

The 2019 coronavirus disease (COVID-19) pandemic is a public health emergency of international concern and poses a challenge to the mental health and sleep quality of front-line medical staff (FMS). The aim of this study was to investigate the sleep quality of FMS during the COVID-19 outbreak in China and analyze the relationship between mental health and sleep quality of FMS.

Methods

From February 24, 2020 to March 22, 2020, a cross-sectional study was performed with 543 FMS from a medical center in Western China. A self-reported questionnaire was used to collect data anonymously. The following tests were used: The Self-Rating Anxiety Scale (SAS) for symptoms of anxiety, the Beck Depression Inventory (BDI) for depressive symptoms, and the Pittsburgh Sleep Quality Index (PSQI) for sleep quality assessment.

Results

Of the 543 FMS, 216 (39.8%) were classified as subjects with poor sleep quality. Anxiety (P<0.001), depression (P<0.001), and the prevalence of those divorced or widowed (P<0.05) were more common in FMS with poor sleep quality than in participants with good sleep quality. The FMS exhibiting co-occurrence of anxiety and depression were associated with worse scores on sleep quality than those medical staff in the other three groups/categories. The difference in sleep quality between the FMS with only depression and the FMS experiencing co-occurrence of anxiety and depression was statistically significant (P<0.05). However, there was no significant difference in sleep quality between the FMS experiencing only anxiety and the FMS with co-occurrence of anxiety and depression (P > 0.05).

Conclusions

During the COVID-19 pandemic, there was a noteworthy increase in the prevalence of negative emotions and sentiments among the medical staff, along with poor overall sleep quality. We anticipate that this study can stimulate more research into the mental state of FMS during outbreaks and other public health emergencies. In addition, particular attention must be paid to enhance the sleep quality of FMS, along with better planning and support for FMS who are continuously exposed to the existing viral epidemic by virtue of the nature of their profession.

Introduction

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease caused by a novel coronavirus strain, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in December 2019 in Wuhan City, in central China and spread rapidly to the rest of the world, including Europe and the United States [1]. It has a high transmission rate and can be transmitted via close human-to-human contact [2, 3]. The World Health Organization (WHO) has declared COVID-19 a Public Health Emergency of International Concern as of 1 February 2020 [4]. Data as received by WHO from national authorities, as of 21 February 2021, there have been 110.7 million confirmed cases of COVID-19, including 2.4 million deaths since the start of the pandemic [5].

As the focal point of epidemic prevention and control, hospitals are the principal settings of confirmed or suspected cases of COVID-19, making them the most susceptible sites for new infections. In the wake of the current viral pandemic, the front-line medical staff (FMS) have indubitably been the most impacted groups, with increased workload involving diagnosis and treatment of new infections, elevated stress levels, reduced or overwhelmed health system capacity, and increased risk of infections [6]. These constant stressors may adversely impact sleep quality and mental health of FMS. In a meta-analysis showed that anxiety was assessed in 12 studies, with a pooled prevalence of 23.2% and depression in 10 studies, with a prevalence rate of 22.8% during the COVID-19 pandemic [7].

It has long been known that medical staff often suffer from sleep disorders and low sleep quality, due primarily to work-related stressors, sleep deprivation and shift work [8]. The COVID-19 outbreak in China remains to be a serious challenge for FMS. These professionals, by virtue of their continuous and intimate association with patients, are not only under high risk of getting infected themselves, but they also suffer from high mental stress, which may lead to sleep disturbances [9]. Qiu et al. [10] found that 39.2% of Chinese medical workers suffered from sleep disorders. However, 51.7% of front-line medical staff had sleep disorders under COVID-19 outbreak in China [9]. Sleep disorders not only increase the risk of infection among medical staff, but also impair their work performance during the pandemic [11, 12], and has a negative impact on health including increased risk of stroke, obesity, diabetes, cancer, osteoporosis, and cardiovascular disease [13]. More alarmingly, individuals experiencing persistent and progressive decline in sleep quality are more likely to develop mental illnesses (such as anxiety and depression) [14] and exhibit suicidal behaviors [15].

Early prevention, proper recognition/diagnosis and treatment of anxiety and depression, along with strategies aimed at improving sleep quality are especially crucial during extraordinarily stressful times, such as during the COVID-19 pandemic, because these strategies may significantly prevent the re-emergence of sleep disorders and mental illness [16]. Maintaining a good sleep quality and mental health can not only help FMS better treat patients, but also help them maintain optimum immune function and prevent infections [17]. Therefore, the purpose of this study was to investigate the mental state and sleep quality of the FMS during the COVID-19 pandemic, to explore the risk factors underlying poor sleep quality, analyze the relationship between mental state and sleep quality, to provide a scientific basis for the prevention and control of mental disorders, and, finally, to suggest strategies aimed at enhancement of sleep quality of medical staff. Further, this study can serve as a primary reference and information guide for hospitals in other countries to help them maintain the mental and physical health of their medical staff as they continue to deal with the possible resurgence of the COVID-19 global pandemic.

Methods

Ethical approval

The study was approved by the Biomedical Research Ethics Committee, West China Hospital of Sichuan University (Approval number: 20200220).

Study design

An observational and cross-sectional clinical study was conducted that included the use of self-reported questionnaires. The questionnaire was built on a professional questionnaire survey network platform called “Wenjuan Xing” (www.wjx.cn) and then was shared on social media WeChat. While constructing the online questionnaire, the integrity check function of the platform was used, meaning the questionnaire could not be submitted unless all questions were answered. All questionnaires were completed anonymously by FMS.

Study participants

We contacted department heads in each department and invited them to forward our questionnaire to their WeChat group of staff to recruit participants. This study included 543 FMS from a medical center in Western China who regularly treated or were in contact with patients infected with COVID-19, during a period spanning from February, 2020 to March, 2020 by convenience sampling. The study participants included doctors, nurses and technicians who worked in high-risk Covid-19 clinical departments, laboratories, and administrative departments. The inclusion criteria were as follows: (1) regular employees, (2) worked at their posts during the survey, (3) WeChat users. All study participants willingly volunteered to participate in the study.

Sample size

Sample size was determined using the formula:

N=z2×p(1p)e2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’ is prevalence rate of 40% from a recent study done in China [10]. According to the formula, N = 369, considering the non-response rate of 20%, at least 443 sample size are needed.

Measures and instruments

The online questionnaire had four sections: sociodemographic, depression symptoms, anxiety symptoms and sleep quality were required. After a brief written informed consent at the beginning of the survey, the questionnaire was answered. Sociodemographic data including age, gender, education, marital status, living with family members or not, employee type and seniority, were also required. Levels of anxiety, levels of depression, and sleep quality were measured using validated clinical questionnaires and scoring systems.

The Self-Rating Anxiety Scale (SAS)

The Self-Rating Anxiety Scale (SAS) was compiled by William W. K. Zung in 1971 [18]. The SAS was used to measure the levels of anxiety of the medical staff, which contained 20 items consisting of four grades, with questions based on feelings of anxiety and mood in the previous seven days. An aggregate score of 20 was then multiplied by 1.25, with higher scores indicating more severe levels of anxiety. The demarcation value of SAS standard deviation is 50 points, with SAS ≤ 50 points judged as “no anxiety state”, and > 50 points considered as “presence of an anxiety state”. The Cronbach’s alpha (Tau-equivalent reliability), as a measure of internal consistency for the use of SAS, was 0.821 [19].

Beck Depression Inventory (BDI)

The BDI was compiled by the clinical psychologist, Aaron T. Beck in 1961 [20], which we employed to measure the levels of depressive mood of the medical staff. Although the BDI contains a 21-question self-report inventory in its original form, a 13-item abbreviated scale was developed in the Early Clinical Drug Evaluation Program and is widely used in research [21]. This refined/reformatted BDI contains 13-question self-rated inventory on a scale of 0–3 to give score of 0–39. The demarcation value of BDI standard deviation is 4 points, BDI ≤ 4 points is judged as “no depression”, and BDI > 4 points is considered as "depression”. The Cronbach’s alpha, for internal consistency for the use of BDI, was 0.8847 [22].

The Pittsburgh Sleep Quality Index (PSQI)

The Pittsburgh Sleep Quality Index (PSQI), developed by D. J. Buysse [23], was used to measure sleep quality using a 19-item scale, containing seven items that included sleep quality, sleep duration, sleep latency, habitual sleep efficiency, sleep disturbance, any use of sleeping medications, and daytime dysfunction over the last month. The seven-component scores are added together to get a global PSQI score. For descriptive purposes, participants with scores below 5 points were considered to have good sleep quality, whereas, participants with scores higher than 5 points had poor sleep quality. The Cronbach’s alpha, as a measure of internal consistency for the use of the PSQI, was 0.811 [24].

Statistical analysis

All data were analyzed using IBM SPSS version 24.0. Measurement data conforming to normal distribution were presented as the means and standard deviation of the mean. Categorical variables were expressed as absolute values and percentages. Measurements between groups and within groups were analyzed using the t-test, Chi-squared test with count data, grade data, using Kruskal-Wallis test analysis. Multivariate logistic regression analysis was performed on the variables that were significant in univariate analysis. The binary logistic regression analyses were used to estimate the odds ratio for each independent variable, to assess which of the factors associated with poor sleep quality. We used ANOVA to compare the differences of PSQI scores among the following groups: “Anxiety only”, “depression only”, “co-occurrence of anxiety and depression”, “neither anxiety nor depression”. Bonferroni’s multiple comparison test was conducted to examine which two means were different. All data analyzed was set at a statistically significant level of p<0.05.

Results

Demographic data of the subjects

A total of 546 FMS completed the questionnaire survey, which included three participants were disagreeing to use their answers for study due to their answers are worthless(n = 2), worried about expose their privacy(n = 1). Hence,543 effective questionnaires, with an effective rate of 99.4%. Most of the participants were women, accounting for 94.3% of the total. In addition, 84.4% of the study subjects were nurses (Table 1).

Table 1. Demographic of front-line medical staff (N = 543).

Variable Frequency Percent (%)
Gender Male 31 5.7
Female 512 94.3
Age (years) 18~34 324 59.7
35~44 130 23.9
45~54 77 14.2
55~64 12 2.2
Marital status Married 394 72.6
Unmarried 137 25.2
Divorced/widowed 12 2.2
Education College degree or below 505 93.0
Bachelor’s degree 28 5.2
Master’s degree or above 10 1.8
Living condition Family cohabitation 362 66.7
Live alone 181 33.6
Department Clinical departments 427 78.6
Executive branch 23 4.3
Logistics department 93 17.1
Profession Doctor 43 7.9
Nurse 458 84.4
Technician 42 7.7
Working experience Mean ± SD 12.0±9.6
BDI score ≤4 440 81.1
>4 103 18.9
Mean ± SD 2.4±3.89
SAS score ≤50 500 92.1
>50 43 7.9
Mean ± SD 37.1±8.76
PSQI score ≤5 327 60.2
>5 216 39.8
Mean ± SD 5.2±3.24

BDI = Beck Depression Inventory.

SAS = Self-Rating Anxiety Scale.

PSQI = Pittsburgh Sleep Quality Index.

SD = Standard deviation.

Analysis of factors affecting sleep quality during COVID-19 outbreak

Among the 543 FMS, 43 (7.9%) were in an anxiety state (SAS>50 points) and 103 (18.9%) had depression (BDI > 4 points). Of the 543 respondents, 216 (39.8%) were classified as subjects with poor sleep quality; anxiety [odds ratio (OR), 4.7; 95% confidence interval (CI), 2.0–11.2], depression (OR, 4.9; 95% CI, 2.9–8.3), and the proportion of those who had divorced/or were widowed [OR, 6.1;95% CI, 1.1–32.7] were more common in FMS with poor sleep quality than in those with good sleep quality (Table 2).

Table 2. Analysis of factors affecting sleep quality [number (percentage %)].
Variables N = 543 Sleep Quality Univariate analysis Multivariate analysis
Good (≤5) Poor (> 5) t/χ2 p-value OR (95%CI) p-value
(n = 327) (n = 216)
Gender
 Male 31 21(6.4%) 10(4.6%) 0.766 0.378
 Female 512 306(93.6%) 206(95.4%)
Age (years)
 18~34 324 205(62.7%) 119(55.0%) 6.498 0.09
 35~44 130 75(22.9%) 55(25.5%)
 45~54 77 38(11.6%) 39(18.1%)
 55~64 12 9(2.8%) 3(1.4%)
Marital status
 Married 394 228(69.7%) 166(76.9%) 16.817*** < 0.001 1.00 [Reference]
 Unmarried 137 97(29.7%) 40(18.5%) 0.5(0.3–1.0) 0.092
 Divorced or widowed 12 2(0.6%) 10(4.6%) 6.1(1.1–32.7) * 0.032
Education
 College degree or below 505 305(93.3%) 200(92.6%) 0.117 0.943
 Bachelor’s degree 28 16(4.9%) 12(5.6%)
 Master’s degree or above 10 6(1.8%) 4(1.9%)
Living condition
 Family cohabitation 362 212(64.8%) 150(69.4%) 1.245 0.264
 Live alone 181 115(35.2%) 66(30.6%)
Department
 Clinical departments 427 250(76.5%) 177(81.9%) 2.699 0.259
 Executive branch 23 14(4.3%) 9(4.2%)
 Logistics department 93 63(19.3%) 30(13.9%)
Profession
 Doctor 43 24(7.3%) 19(8.8%) 0.401 0.818
 Nurse 458 278(85.0%) 180(83.3%)
 Technician 42 25(7.6%) 17(7.9%)
Working experience 11.1±9.46 13.3±9.73 -2.753** 0.006 1.0(0.9–1.0) 0.243
Anxiety
 Yes 43 9(2.8%) 34(15.7%) 30.09*** < 0.001 4.7(2.0–11.2) *** <0.001
 No 500 318(97.2) 182(84.3%) 1.00 [Reference]
Depression
 Yes 103 27(8.3%) 76(35.2%) 61.366*** < 0.001 4.9(2.9–8.3) *** <0.001
 No 440 300(91.7%) 140(64.8%) 1.00 [Reference]

OR = Odds Ratio.

CI = Confidence Interval.

*0.05 > p-value > = 0.01.

**0.01 > p-value > = 0.001.

***p-value < 0.001.

Comparison of the total score and subscale scores for sleep quality of FMS with different demographic characteristics and mental states during COVID-19 outbreak

The total score for sleep quality and other scores for its seven subscales in FMS with anxiety or depression were higher than those without anxiety or depression. The score for overall sleep quality, the amount of sleep and sleep efficiency of divorced/widowed FMS were higher than the other FMS. In addition, the study also found that in terms of sleep latency scores, the values were higher for female FMS than that of males. The sleep latency scores of the FMS living alone ware higher than that of those living with their families. The hypnotic drug score of FMS aged 55–64 years was higher than that of other age groups (P < 0.05) (Table 3).

Table 3. Comparison of the total score and subscales of sleep quality of front-line medical staff with different demographic characteristics and mental state.
Variables N = 543 PSQI score Sleep quality Sleep latency The amount of sleep Sleep efficiency Sleep disorders The hypnotic drug Diurnal dysfunction
Gender
 Male 31 5.20±3.45 0.90±0.70 0.65±0.66 0.84±0.73 0.58±0.57 0.90±0.53 0.09±0.19 1.13±0.99
 Female 512 5.19±3.23 0.93±0.746 0.91±0.71 0.70±0.65 0.58±0.89 0.94±0.58 0.12±0.49 1.0±0.9
t -0.309 -0.207 -2.050* 1.147 0.015 -0.334 -1.354 0.747
P 0.758 0.836 0.041 0.252 0.988 0.738 0.176 0.455
Age (years)
 18~34 324 4.98±0.054 0.90±0.747 0.93±0.69 0.62±0.66 0.53±0.86 0.94±0.61 0.08±0.37 0.99±0.86
 35~44 130 5.12±0.080 0.96±0.720 0.88±0.73 0.72±0.57 0.57±0.93 0.92±0.54 0.06±0.34 1.02±0.93
 45~54 77 6.05±0.70 1.06±0.71 0.83±0.69 1.04±0.61 0.81±1.01 0.97±0.53 0.27±0.77 1.06±1.01
 55~64 12 5.33±0.74 0.67±0.98 0.67±0.77 0.75±0.96 0.42±0.99 1.00±0.60 0.67±1.15 1.17±0.93
F 2.293 1.671 0.843 1.492 2.004 0.208 9.545*** 0.264
P 0.077 0.172 0.471 0.222 0.112 0.891 < 0.001 0.852
Marital status
 Married 394 5.34±3.27 0.94±0.74 0.91±0.71 0.74±0.64 0.63±0.94 0.96±0.56 0.12±0.49 1.04±0.91
 Unmarried 137 4.56±3.10 0.88±0.72 0.85±0.67 0.58±0.68 0.42±0.79 0.85±0.63 0.07±0.39 0.91±0.85
 Divorced or widowed 12 6.75±0.76 1.25±0.75 1.00±0.85 1.00±0.42 0.75±0.75 1.08±0.51 0.25±0.86 1.42±0.99
F 4.417* 1.401 .434 4.553* 3.052* 2.116 1.056 2.299
P 0.013 0.247 0.648 0.011 0.048 0.122 0.348 0.101
Education
 College degree or below 505 5.18±3.27 0.92±0.74 0.90±0.71 0.71±0.66 0.60±0.92 0.94±0.58 0.12±0.50 0.99±0.89
 Bachelor’s degree 28 5.04±2.48 0.93±0.60 0.86±0.59 0.71±0.53 0.21±0.41 0.93±0.53 0 1.39±0.95
 Master’s degree or above 10 5.30±4.02 1.20±1.03 0.80±0.78 0.60±0.51 0.50±1.08 1.00±0.94 0 1.20±0.91
F 0.034 0.672 0.147 0.136 2.447 0.061 1.138 2.922
P 0.967 0.511 0.864 0.873 0.088 0.941 0.321 0.055
Living condition
 Family cohabitation 362 5.20±3.06 0.93±0.72 0.81±0.71 0.69±0.63 0.56±0.85 0.96±0.55 0.10±0.44 1.01±0.89
 Live alone 181 5.13±3.59 0.93±0.78 0.94±0.70 0.73±0.70 0.61±1.00 0.88±0.63 0.14±0.55 1.01±0.93
t 0.243 0.041 1.982 -0.692 -0.635 1.504 -1.003 0
P 0.808 0.967 0.048 0.489 0.526 0.133 0.316 1.000
Department
 Clinical departments 427 5.29±3.26 0.95±0.75 0.94±0.71 0.70±0.65 0.58±0.89 0.96±0.59 0.12±0.49 1.02±0.90
 Executive branch 23 5.13±2.89 0.96±0.76 0.74±0.61 0.78±0.73 0.43±0.84 0.91±0.41 0 1.30±0.97
 Logistics department 93 4.67±3.21 0.82±0.69 0.74±0.64 0.71±0.63 0.59±.99 0.82±0.57 0.11±0.47 0.88±0.89
F 1.403 1.295 3.611* 0.162 0.303 2.462 0.701 2.207
P 0.247 0.275 0.028 0.851 0.739 0.086 0.497 0.111
Profession
 Doctor 43 5.23±3.10 0.88±0.69 0.81±0.62 0.70±0.55 0.51±0.91 1.02±0.59 0.07±0.33 1.23±0.99
 Nurse 458 5.14±3.27 0.92±0.76 0.91±0.71 0.69±0.65 0.58±0.90 0.92±0.60 0.12±0.50 0.99±0.88
 Technician 42 5.50±3.08 1.05±0.58 0.83±0.73 0.90±0.75 0.60±0.93 1.00±0.38 0.07±0.34 1.05±1.01
F 0.243 0.626 0.551 2.065 0.129 0.829 0.408 1.488
P 0.784 0.535 0.577 0.128 0.879 0.437 0.665 0.227
Anxiety
 Yes 43 8.74±3.88 1.56±0.88 1.44±0.66 1.09±0.75 0.86±1.10 1.56±0.79 0.30±0.86 1.93±0.91
 No 500 4.87±2.99 0.88±0.70 0.85±0.69 0.67±0.63 0.55±0.88 0.88±0.53 0.10±0.43 0.93±0.86
t 7.929*** 5.957*** 5.410*** 4.066*** 2.132*** 7.615*** 2.672*** 7.264***
P < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001
Depression
 Yes 103 7.96±3.39 1.44±.77 1.29±0.73 0.96±0.72 0.88±1.09 1.36±0.60 0.23±0.70 1.80±0.80
 No 440 4.52±2.84 0.81±0.68 0.80±0.66 0.65±0.62 0.51±0.84 0.84±0.53 0.09±0.41 0.83±0.82
t 10.626*** 8.139*** 6.535*** 4.428*** 3.840*** 8.658*** 2.786*** 10.767***
P < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001

*0.05 > p-value > = 0.01.

**0.01 > p-value > = 0.001.

***p-value < 0.001.

The effect of mental health on sleep quality during COVID-19 outbreak

A total of 543 FMS were divided into four groups, according to whether they experienced anxiety or depression. There were 16 (2.9%) with “anxiety only” (Group 1), 76 (14.0%) with “depression only” (Group 2), 27 (5.0%) with “co-occurrence of anxiety and depression” (Group 3), and 424 (78.1%) with “neither anxiety nor depression” (Group 4). The results indicated that the PSQI score of the medical staff with co-occurrence of anxiety and depression was the highest and their sleep quality was the worst (Table 4). Multiple comparisons showed that there was a significant difference between Group 4 and the other three groups (group 1, 2, and 3) (P<0.05), suggesting that the sleep quality of FMS with only anxiety, only depression, and co-occurrence of anxiety and depression was worse than those with neither anxiety nor depression. The difference in sleep quality between Group 2 and Group 3 was statistically significant (P <0.05), indicating that the sleep quality of FMS with co-occurrence of anxiety and depression was worse than those with depression alone. However, no significant differences between Group 1 and Group 3 were observed (P > 0.05) (Table 5).

Table 4. Analysis of variance between different groups, endpoint: PSQI.
Variables N (%) M±SD F P-value
Anxiety only(group1) 16 (2.9) 7.58±3.15 50.8*** < 0.001
Depression only (group 2) 76(14.0) 8.25±4.01
Both anxiety and depression (group 3) 27(5.0) 9.04±3.85
Neither anxiety nor depression (group4) 424(78.1) 4.38±2.69

The statistical methods used for comparisons were the One-Way Anova (normal distribution).

M = Mean.

SD = Standard difference.

***p-value < 0.001.

Table 5. Repeated measures of each dependent variable.
Comparison group MD SE P-value 95%CI
1and 2 -0.671 0.791 0.396 -2.22–0.88
2and 3 -1.458 0.644 0.024 -2.72–-0.19
2and 4 3.197 0.358 0.000 2.49–3.90
1and 3 -0.787 0.907 0.386 -2.57–0.99
1and 4 3.868 0.732 0.000 2.43–5.31
3and 4 4.655 0.571 0.000 3.53–5.78

MD = Mean difference.

SE = Standard Error.

CI = confidence interval.

Discussion

Previous studies have suggested that medical workers are particularly vulnerable to sleep disorders even during times of relative tranquility [25]. In addition, the rapid spread of the viral outbreak, inadequate early-stage testing/screening, and lack of targeted anti-viral treatments toward COVID-19 all constituted a pressing challenge for the FMS in numerous countries, exerting great psychological pressure on them. Therefore, the purpose of this study was to investigate the mental state and sleep quality of FMS during the COVID-19 outbreak in a hospital setting providing primary care and screen for COVID-19. Our results suggest that 7.9% FMS had anxiety and 18.9% had depression are lower than previous studies, reported in Wuhan during the same period. Potential differences, however, could be explained on the basis of the extremely high infectious potential rate in Wuhan but also the experience acquired in the interim in our hospital. Additionally, 39.8% of FMS had poor sleep quality, which was lower than the 51.7% of FMS experiencing poor sleep quality in Wuhan [9]. The high prevalence of poor sleep quality in Wuhan could be attributed to the fact that the city was the epicenter of the pandemic, hence, the high intensity and excessive pressure from rescue/relief efforts, as well as frequent/irregular shift work, could have culminated in more serious and prevalent sleep disorders for FMS.

There were several factors that may have resulted in poor sleep quality in FMS. The study demonstrated anxiety [odd ratio (OR), 4.7; 95% confidence interval (CI), 2.0, 11.2], depression (OR, 4.9; 95% CI, 2.9, 8.3), and prevalence of those who had divorced/widowed (OR, 6.1;95% CI, 1.1, 32.7) were more common in FMS with poor sleep quality than in participants with good sleep quality during the COVID-19 outbreak. COVID-19 can be transmitted via close human-to-human contact [3] and FMS are among the most vulnerable groups to infection. Therefore, anxiety and depression are also common negative emotions experienced by FMS during the COVID-19 outbreak [26]. Negative emotions and repetitive negative thinking patterns are associated with problems in initiating and maintaining sleep [27]. Our results showed that compared with the FMS without anxiety or depression, in FMS with either anxiety or depression, the duration of sleep decreased, sleep latency increased, sleep efficiency decreased, and wake-up time increased. Sleep disorders and diurnal dysfunction are serious concerns during the COVID-19 outbreak, thus, leading to poor sleep quality. Marital status is also a risk factor for poor sleep quality in FMS during the COVID-19 outbreak. The poor sleep quality of divorced/widowed FMS is mainly reflected in the lack or low efficiency of sleep during the COVID-19 outbreak, possibly due to the fact that divorced/widowed FMS may lack certain social support (peer communication and emotional support) during the outbreak, which indirectly leads to the decline of sleep quality [28]. The study also found that in terms of sleep latency scores, the values were higher in female FMS than in their male counterparts, and FMS living alone had higher scores those living with their families. In China, at the end of a paid professional work shift, women are generally expected to take on additional family responsibilities. The fact that women are expected to simultaneously assume multiple social roles invariably exerts a disproportionate pressure on women, which may lead to increased sleep latency. We also found that the hypnotic drug score of FMS aged 55–64 years was higher than that of other age groups. This suggests that older FMS are more likely to consume hypnotic drugs to improve the quality of sleep.

During the epidemic period, a large number of medical staff were sent to Wuhan for support, resulting in a shortage of medical staff in our hospital. As a consequence, the clinical medical staff needed to alternate their shifts frequently to accommodate the busy clinical work. Medical staff on duty must always be on active standby. If they are repeatedly awakened at night, the steady state of sleep/wake cycle will be interrupted, and the sleep state will be fragmented, which will make it difficult to fall asleep again and lead to sleep disorder. When the medical staff on shift attempt to supplement sleep during daytime, they are invariably exposed to strong natural light and a noisy rest environment during the day, which is conducive to premature and spontaneous sleep termination during the sleep period that ensues the night shift. As a result, the overall sleep duration is significantly shortened, resulting in an overall decline in sleep quality. Persistent work-related pressure, frequent sleep deprivation and irregular shift work, collectively precipitate sleep disorders and sleep schedule disorders, which ultimately lead to a decline in overall sleep quality.

We analyzed the relationship between mental state and sleep quality. The results suggest that the sleep quality of the FMS experiencing only anxiety, only depression, or co-occurrence of anxiety and depression was worse than those with neither anxiety nor depression during the COVID-19 outbreak. In addition, the results indicate that the sleep quality of FMS with co-occurrence of anxiety and depression was worse than those with only depression. Depression can lead to poor sleep quality, but the overlapping or potentially cumulative effects of depression and anxiety can exacerbate the decline in sleep quality. A study also concluded that patients with both depression and anxiety symptoms have a higher incidence of sleep disorders [29]. However, in our study, the sleep quality of FMS with anxiety was not much different than the sleep quality of FMS with both anxiety and depression. It is plausible that patients with anxiety are prone to experiencing serious sleep disorders, because sleep disorders and anxiety have a common/underlying pathogenesis: hyperactivity caused by disorders of neurotransmitter systems, such as cholinergic and GABA [30].

Sleep disorders could be an early symptom, part of a prodrome, of an underlying depressive or anxiety disorder. Similarly, sleep disorders might also exist as a separate, comorbid disorder that either gave rise to or developed from an undiagnosed psychiatric condition. Furthermore, anxiety and depression have bidirectional association with sleep quality [31]. Continuous poor sleep quality will lead to decreased daytime function, emotional instability, and mental exhaustion, thus increasing the risk of depression and anxiety [32]. Additionally, it is known that anxiety, depression and sleep disorders intersect by mutually affecting and triggering/exacerbating each other. The fundamental underpinning of insomnia is through to be cognition in the form of anxiety [33]. Depression can predispose individuals to unreasonable beliefs about sleep disorders, leading to a more serious anxiety state. Insomnia forms an emotional memory in the anxiety and depression, conditionally activating sympathetic nervous system, further aggravating the existing state of anxiety, and becoming a self-sustaining malignant cycle, which keeps individuals in a highly awake state, leading to persistent sleep disorders. Particularly during the COVID-19 outbreak, FMS faced greater risk of infection and work stress, as well as frequent policy changes, unclear case management criteria, and other ambiguous conditions that led to depression and anxiety, which have contributed to the higher incidence of sleep disorders.

Therefore, under the stress of an epidemic outbreak, hospitals must be vigilant and proactive in assessing the mental health and sleep quality of FMS as well as extending remediation efforts to help them cope with existing mental health/sleep quality issues. During clinical intervention of FMS who experience psychological problems and sleep disorders, the clinicians should look for the potential comorbidity mental state, so as to determine the appropriate treatment modality to break the vicious cycle of anxiety, depression and sleep disorders, thereby, improving the mental health and sleep quality.

For most FMS, what they need is more undisturbed rest [34]. We advocated that hospitals should establish a shift system to allow their FMS to rest and take turns to undertake high-risk and high-pressure work. A detailed plan in advance may improve the effectiveness of post-disaster interventions, such as effective risk communication and the provision of psychological first aid [35]. Through effective training and support, hospitals can provide online consultation platforms, disseminate information on how to reduce the risk of transmission amongst FMS in a clinical setting, and provide timely and authoritative information on pandemic dynamics, which may be instrumental in reducing the psychological impact on FMS. In addition, a tight social support network can help medical staff reduce or better manage their anxiety levels, thus, indirectly help to improve sleep quality. Therefore, it is suggested that family members or close friends provide a compassionate and supportive social network for FMS as a form of emotional and social support. Also, hospitals and governments should provide welfare subsidies to FMS in order to alleviate financial burdens on them during these extraordinary times.

When FMS experience a decline in sleep quality or insomnia, it is advisable that a number of rectifying measures be adopted to improve sleep quality, including sleep health education, relaxation training, and cognitive behavioral therapy to conduct self-regulation (Cognitive behavioral therapy for insomnia, CBT-I). As a final resort, if the aforementioned measures are ineffective, hypnotics, as psychoactive compounds, can be administered under the guidance of psychiatrists. It should also be underscored that excessive publicity or over-reporting of the adverse circumstances of FMS fighting the COVID-19 can do a disservice to them by demoralizing them, which may lead to symptoms such as over-excitement, irritability, psychological distress, unwillingness to take sufficient rest, etc. It is, therefore, our suggestion that media outlets and news agencies avoid excessive reporting and coverage of the circumstances of the FMS fighting the epidemic.

Limitations

This investigation has several limitations that need to be considered in the interpretation of our results. First, this is a cross-sectional study. As such, we cannot infer causality in the interpretation of the findings. Second, our survey subjects were derived from one specific hospital through convenience sampling, and the proportion of male subjects in this study was low, thus the representativeness may be reduced. Third, the participants completed the self-reported questionnaires using the WeChat application and mobile devices, which might lead to self-selection bias. Nevertheless, assessing anxiety and depressive symptoms via an individualized interview with a qualified psychiatrist would have been ideal. Moreover, the causality or subordination between anxiety, depression and poor sleep quality is not self-evident. Therefore, the relationship between anxiety, depression, and sleep quality of medical staff in public health emergencies may have other directions, which can be explored in future studies.

Conclusions

An observational and cross-sectional clinical study was conducted to investigate the mental state and sleep quality of the FMS during the COVID-19 outbreak in a hospital setting. The results suggested that anxiety, depression, and divorce/bereavement were more common in the FMS with poor sleep quality than in those with good sleep quality. The sleep quality of FMS with co-occurrence of anxiety and depression was worse than that of the medical staff with depression alone. Therefore, during the epidemic period, particular attention must be paid to the mental well-being and sleep quality of FMS. Strategies aimed at prevention and timely intervention of sleep disorders, anxiety and depression in FMS are crucial to help us effectively treat and contain the recent pandemic in hospital settings.

Supporting information

S1 File. The data used and/or analyzed during the current study.

(XLS)

Acknowledgments

The authors thank the medical staff who participated in the study.

Data Availability

All relevant data are within the paper and its S1 File.

Funding Statement

This research was received grant from funding 2019 novel coronavirus disease technology research project of West China Hospital of Sichuan University (NO: HX-2019-nCov-034). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Decision Letter 0

Stephan Doering

1 Feb 2021

PONE-D-20-30673

The Effect of mental health on Sleep Quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study

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Reviewer #2: Yes

**********

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Reviewer #1: The Current manuscript addressing the topic “The Effect of mental health on Sleep Quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study” is a good effort to explore the mental health and quality of sleep of front-line medical staff during pandemic like COVID-19. Overall the article is well written but I have a few suggestions and comments,

Abstract

Kindly improve the presentation of the structured abstract. In the presentation of results, it is suggested to use only P-values instead of OR, CI.

Introduction

It is suggested to include the data of the outbreak during the period when the study was conducted to provide more context to interpret the findings.

Methods

The methodology of the study is not described properly.

Is the study conducted physically or by using an online platform to administer the questionnaire?

Is there any strategy used to address the missing data?

There is no description, how the sample size was calculated, and how the participants were recruited to achieve the final number of participants for analysis?

There are no details provided on what basis multivariate logistic regression applied to different variables.

Results

It is advisable to adopt a dual approach to report cut-offs of BDI, SAS, and PSQI with its continuous score in table 1.

Kindly clarify what test applied to analyze the factors affecting sleep quality is it the Chi-square test or logistic regression analysis also revise p-values presented in table 2.

Discussion.

To improve the discussion section and as well as the introduction section it is suggested to provide a link between the effect of COVID-19 on the mental health & sleep quality of healthcare workers.

I would suggest providing references to similar studies conducted during the current pandemic in different countries, like one recently published study “Arshad et al. Assessing the Impact of COVID-19 on the Mental Health of Healthcare Workers in Three Metropolitan Cities of Pakistan. Psychology research and behavior management, 13, 1047. Doi.10.2147/PRBM.S282069.

Limitation

Is there any strategy used to remove biases, if not mention it as a limitation to the current study.

Reviewer #2: Estimated Authors,

Estimated Editors,

I've appreciated your valuable paper on the Effect of mental health on Sleep Quality of front-line medical staff during the

COVID-19 outbreak in China. Even though the results of your study were largely not unexpected (i.e. we are dealing with a significant stressor event, and its consequences are both consistent with previous evidences and international daily experience of healthcare workers), it doesn't mean that such results may be of limited interest - viceversa, I'm confident that the work of Meng et al. may contribute to the global effort against the ongoing pandemic.

In my opinion, introduction, results and discussion are properly reported. My only concern refers to the sample size. Authors should explain whether their sample was collected by convenience or a preventive power analysis was otherwise modelled. It is particularly important as Authors did perform a multivariate analysis, whose reliability should be discussed accordingly to the actual reliability of statistical estimates.

**********

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Reviewer #1: No

Reviewer #2: Yes: Matteo Riccò

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PLoS One. 2021 Jun 24;16(6):e0253753. doi: 10.1371/journal.pone.0253753.r002

Author response to Decision Letter 0


11 Mar 2021

Dear editor:

Thanks a lot for your reviews to our manuscript. We acknowledge your comments and constructive suggestions very much, which are valuable for improving the quality of our manuscript. We have revised the manuscript according to the reviewers’ comments in detail. We hope, with these modifications and improvements based on your suggestions and the reviewers’ comments, the quality of our manuscript would meet the publication standard of PLOS ONE.

The revisions have been done in the attached manuscript. Some explanations regarding the revisions of our manuscript are as follows. If you have any question, please contact us without hesitate.

Academic editor

Q1:Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

A1:Thank you for bringing up this important point. We have revised the format of the article as required.

Q2:In your Methods section, please provide additional information about the participant recruitment method and the demographic details of your participants. Please ensure you have provided sufficient details to replicate the analyses such as: a description of any inclusion/exclusion criteria that were applied to participant recruitment, a statement as to whether your sample can be considered representative of a larger population, a description of how participants were recruited. descriptions of where participants were recruited and where the research took place, a sample size calculation.

A2: Thank you for bringing up this important point. We have revised the Methods section and supplemented the content which was omitted before.

This study included 543 FMS from a medical center in Western China who regularly treated or were in contact with patients infected with COVID-19, during a period spanning from February, 2020 to March, 2020. The inclusion criteria were as follows: (1) regular employees, (2) worked at their posts during the survey, (3) WeChat users. All study participants willingly volunteered to participate in the study.

The subjects of this study were selected from the medical staff of West China Hospital of Sichuan University,which is one of the largest medical centers in China. After the outbreak of the epidemic, we not only sent medical staff to Wuhan to treat the infected people in the first time, but also undertook the treatment of the infected people in the area where the hospital is located. Besides, in this study, 84.4% of the research population were nurses, and 94.3% of the research population were women, which was consistent with the occupation and sex distribution of the Chinese healthcare system. However, our survey subjects were derived from one specific hospital through convenience sampling, thus the representativeness may be reduced, which may be treated as a limitation of the study.

We contacted department heads in each department and invited them to forward our questionnaire to their WeChat group of staff to recruit participants.

The questionnaire was built on a professional questionnaire survey network platform called“Wenjuan Xing” (www.wjx.cn) and then was shared on social media WeChat.

Sample size was determined using the formula:

N=(z^2×p(1-p))/e^2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’ is prevalence rate of 40% from a recent study done in China.

Q3: About financial disclosure: please address the following queries:

Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.

State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

If any authors received a salary from any of your funders, please state which authors and which funders.

A3: This research was received grant from funding 2019 novel coronavirus disease technology research project of West China Hospital of Sichuan University (NO: HX-2019-nCov-034). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. None of the authors received a salary from the funders.

Reviewer #1

Abstract: Kindly improve the presentation of the structured abstract. In the presentation of results, it is suggested to use only P-values instead of OR, CI.

A: Thanks for the detailed suggestion. We have modified it according to your suggestion.

Introduction: It is suggested to include the data of the outbreak during the period when the study was conducted to provide more context to interpret the findings.

A: Thanks for the detailed suggestion. We supplemented studies on the incidence of anxiety, depression, and sleep disorders among health care workers during the epidemic. such as,in a meta-analysis showed that anxiety was assessed in 12 studies, with a pooled prevalence of 23.2% and depression in 10 studies, with a prevalence rate of 22.8% during the COVID-19 pandemic. Qiu et al found that 39.2% of Chinese medical workers suffered from sleep disorders. However, 51.7% of front-line medical staff had sleep disorders under COVID-19 outbreak in China.

Methods:

Thank you for your insightful advisement and comments on the Methods section. All your questions are answered below.

Q1: Is the study conducted physically or by using an online platform to administer the questionnaire?

A1: The questionnaire was built on a professional questionnaire survey network platform called “Wenjuan Xing” (www.wjx.cn) and then was shared on social media WeChat.

Q2: Is there any strategy used to address the missing data?

A2: While constructing the online questionnaire, the integrity check function of the platform was used, meaning the questionnaire could not be submitted unless all questions were answered.

Q3: There is no description, how the sample size was calculated, and how the participants were recruited to achieve the final number of participants for analysis?

A3: Sample size was determined using the formula:

N=(z^2×p(1-p))/e^2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’ is prevalence rate of 40% from a recent study done in China. According to the formula, N=369, considering the non-response rate of 20%, at least 443 sample size are needed. We contacted department heads in each department and invited them to forward our questionnaire to their WeChat group of staff to recruit participants. A total of 546 FMS completed the questionnaire survey, which included three participants were disagreeing to use their questionnaire for study due to their answers are worthless(n=2), worried about expose their privacy(n=1). Hence,543 effective questionnaires for analysis.

Q4: There are no details provided on what basis multivariate logistic regression applied to different variables.

A4: Multivariate logistic regression analysis was performed on the variables that were significant in univariate analysis.

Results:

Q1: It is advisable to adopt a dual approach to report cut-offs of BDI, SAS, and PSQI with its continuous score in table 1.

A1:Thanks for the detailed suggestion. We have made modifications according to your suggestions and the format of the whole table has been revised.

Q2: Kindly clarify what test applied to analyze the factors affecting sleep quality is it the Chi-square test or logistic regression analysis also revise p-values presented in table 2.

A2: The binary logistic regression analyses were used to estimate the odds ratio for each independent variable, to assess which of the factors associated with poor sleep quality. In addition, p-values presented in table 2 have been revised.

Discussion:

Q: To improve the discussion section and as well as the introduction section it is suggested to provide a link between the effect of COVID-19 on the mental health & sleep quality of healthcare workers.

A: Thank you for pointing it out. In fact, anxiety and depression have bidirectional association with sleep quality. Continuous poor sleep quality will lead to decreased daytime function, emotional instability, and mental exhaustion, thus increasing the risk of depression and anxiety. Additionally, it is known that anxiety, depression and sleep disorders intersect by mutually affecting and triggering/exacerbating each other. Particularly during the COVID-19 outbreak, FMS faced greater risk of infection and work stress, as well as frequent policy changes, unclear case management criteria, and other ambiguous conditions that led to depression and anxiety. Insomnia forms an emotional memory in the anxiety and depression, conditionally activating sympathetic nervous system, further aggravating the existing state of anxiety, and becoming a self-sustaining malignant cycle, which keeps individuals in a highly awake state, leading to persistent sleep disorders.

Limitation:

Q: Is there any strategy used to remove biases, if not mention it as a limitation to the current study.

A: Thank you for bringing up this important point. The participants completed the self-reported questionnaires using the WeChat application and mobile devices, which might lead to self-selection bias. Therefore, it will be a limitation of this study.

Reviewer #2

Q: In my opinion, introduction, results and discussion are properly reported. My only concern refers to the sample size. Authors should explain whether their sample was collected by convenience or a preventive power analysis was otherwise modelled. It is particularly important as Authors did perform a multivariate analysis, whose reliability should be discussed accordingly to the actual reliability of statistical estimates.

A: Thank you very much for your very important suggestions and comments on the sample size. In fact, a convenience sampling method was used to recruit participants in this study. According to inclusion and exclusion criteria,a total of 546 FMS completed the questionnaire survey, which included three participants were disagreeing to use their questionnaire for study due to their answers are worthless(n=2), worried about expose their privacy(n=1), 543 effective questionnaires for analysis. Based on the calculation method of cross-sectional study sample size, at least 443 sample size are needed for this study. Hence, the participants we recruited reached the estimated sample size.

Sample size was determined using the formula:

N=(z^2×p(1-p))/e^2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’is prevalence rate of 40% from a recent study done in China. According to the formula, N=369, considering the non-response rate of 20%, at least 443 sample size are needed.

Attachment

Submitted filename: 1.Response to Reviewers.docx

Decision Letter 1

Stephan Doering

9 Apr 2021

PONE-D-20-30673R1

The Effect of mental health on Sleep Quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study

PLOS ONE

Dear Dr. Meng,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. The reviewers basically are in favor of your manuscript, however, Reviewer two raises one important issue. May I ask you to take care of that? Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Stephan Doering, M.D.

Academic Editor

PLOS ONE

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Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

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Reviewer's Responses to Questions

Comments to the Author

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Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

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Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have adequately answered all of my queries in their revised submission and I hope that if this manuscript is accepted it will definitely get attention of the readers.

Reviewer #2: Estimated Authors,

I've read with interest your revised paper. The main text has been largely amended in accordance with my previous recommendations. However, a minor remark regarding the section on the sample size calculation:

you wrote:

Sample size was determined using the formula:

N=(z^2×p(1-p))/e^2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’is

prevalence rate of 40% from a recent study done in China. According to the formula,

N=369,

It is rather unclear what the prevalence rate of 0.4 refers to. Please explain.

**********

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Reviewer #1: No

Reviewer #2: Yes: Matteo Riccò

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PLoS One. 2021 Jun 24;16(6):e0253753. doi: 10.1371/journal.pone.0253753.r004

Author response to Decision Letter 1


5 May 2021

Academic editor

Q:Please review your reference list to ensure that it is complete and correct.

A: Thank you for bringing up this important point. We have revised the format of the references as required. In addition, two references were replaced, the 33rd and 35th respectively. The 33rd is the research published in Chinese journals, and the 35th is the operation manual. Readers may not get the full text, so we use the relevant references instead.

Reviewer#2

Q: Sample size was determined using the formula:

N=(z^2×p(1-p))/e^2

where ‘z’ is 1.96 at 95% confidence interval, ‘e’ is margin of error at 5% and ‘p’ is prevalence rate of 40% from a recent study done in China. According to the formula, N=369, It is rather unclear what the prevalence rate of 0.4 refers to. Please explain.

A: Thank you for pointing it out. In fact, the aim of this study was to investigate the sleep quality of FMS during the COVID-19 outbreak in China and analyze the relationship between mental health and sleep quality of FMS. The logistic regression analyses were used to estimate the odds ratio for each independent variable, to assess which of the factors associated with sleep disorders. Therefore, the prevalence rate of 0.4 refers to the prevalence rate of sleep disorders in Chinese healthcare professionals under the outbreak of COVID-19.

Attachment

Submitted filename: 2.Response to Reviewers.docx

Decision Letter 2

Stephan Doering

14 Jun 2021

The Effect of mental health on Sleep Quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study

PONE-D-20-30673R2

Dear Dr. Meng,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Stephan Doering, M.D.

Academic Editor

PLOS ONE

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: All my concerns have been addressed. Therefore, I've no further recommendations to the study Authors, and I endorse the final publication of this paper.

**********

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Reviewer #2: Yes: Matteo Riccò

Acceptance letter

Stephan Doering

16 Jun 2021

PONE-D-20-30673R2

The effect of mental health on sleep quality of front-line medical staff during the COVID-19 outbreak in China: A cross-sectional study

Dear Dr. Meng:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Professor Stephan Doering

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 File. The data used and/or analyzed during the current study.

    (XLS)

    Attachment

    Submitted filename: 1.Response to Reviewers.docx

    Attachment

    Submitted filename: 2.Response to Reviewers.docx

    Data Availability Statement

    All relevant data are within the paper and its S1 File.


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