Assessing the impact of COVID-19 pandemic on ambulance transports for self-harm: a population-based study in Osaka Prefecture, Japan

Abstract

Objectives

The COVID-19 pandemic might have affected emergency medical services transports for self-harm in Japan. However, the available data are insufficient to fully understand the pandemic’s impact on ambulance transports due to self-harm. This study aimed to investigate the change in the incidence of ambulance transports for self-harm from 2018 to 2021 and to identify vulnerable age groups during the pandemic.

Design

A population-based observational study using a database from the Osaka Prefectural Government.

Setting

The database covers the entire area of Osaka Prefecture and included information on ambulance transports and hospital details.

Participants

Ambulance transport of patients due to self-harm from 2018 through 2021 was investigated.

Primary outcome measures

The primary outcome was the incidence of ambulance transport for self-harm.

Results

We analysed 10 843 patients. Their median age was 38 years, and 69.0% were female. We observed an increasing trend of the incidence rate in cases per 100 000 population per year from 29.4 in 2018 to 31.2 in 2021. However, after adjusting for age group, sex and month, there was no difference in the incidence of ambulance transport due to self-harm in 2019 (adjusted incidence rate ratio (aIRR) 1.007; 95% CI 0.955 to 1.063), 2020 (aIRR 1.041; 95% CI 0.987 to 1.098) and 2021 (aIRR 1.022; 95% CI 0.968 to 1.078), compared with 2018. We observed no difference in 21-day mortality from 2018 through 2021. In the age group of 20–29 years, despite no difference in 2019 compared with 2018, we found an 11.7% increase in the incidence of ambulance transport due to self-harm in 2020 (aIRR 1.117; 95% CI 1.002 to 1.245) and no difference in 2021.

Conclusions

There was no difference in the incidence of ambulance transport due to self-harm and 21-day mortality from 2018 through 2021. However, the incidence rate of ambulance transport due to self-harm in 2020 increased in the age group of 20–29 years.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• Population-based study that covered Osaka area, which has an almost complete study population minimising selection bias, described an increase in incidence during the pandemic.

• Calculated age-stratified incidence rates to identify vulnerable age groups through the pandemic and identified that the incidence rate of ambulance transport due to self-harm in 2020 increased in the age group of 20–29 years, which was the largest age group.

• Not diagnosed by psychiatrists which could lead to both selection and information biases.

• Our findings may not be fully applicable to other areas that have different healthcare systems, legislation and baseline emergency system.

Introduction

The COVID-19 had a significant impact on mental health worldwide.^1–5 To mitigate the spread of the virus, various non-pharmaceutical interventions (NPIs), such as lockdowns, travel restrictions and social distancing, were adopted by many countries.^{6 7} A previous systematic review supported the effectiveness of physical distancing and wearing masks to decrease the risk of infection.⁸ However, these infection control measures, while necessary to limit person-to-person transmission and reduce morbidity and mortality caused by COVID-19, can have negative effects on mental health, as social and physical interactions are crucial for maintaining well-being. Additionally, restrictions on economic activity can lead to increased unemployment and financial hardships, which may significantly affect mental health problems.⁹ Given the urgency of the situation, research on mental health problems and potential strategies to address them during the COVID-19 pandemic is crucial.¹⁰

Self-harm is a significant public health concern among mental health problems and a common reason for ambulance transports. Previous reports suggested that lockdowns in England and Western Australia have been possibly associated with a decrease in hospital visits for self-harm, although several reports worldwide indicate an increase in the incidence of self-harm during the COVID-19 pandemic.^11–17 The healthcare systems in Japan have been significantly impacted by the pandemic. The Japanese government declared a state of emergency in the prefectures, such as Tokyo and Osaka, that faced a surge in infections. Furthermore, Japanese local governments implemented various NPIs such as temporary school closures, encouraging teleworking, urging people to stay indoors, cancelling large gatherings and requesting restaurants and bars to close temporarily.

Emergency medical services (EMS) transports related to self-harm in Japan may have been affected by the COVID-19 pandemic and associated behavioural restrictions.^{18 19} Despite the ongoing research on the impact of the COVID-19 pandemic, there are currently not enough data to fully understand how ambulance transports related to mental health issues have been affected. The purpose of this study was to investigate whether there has been an increase in the incidence of ambulance transports for self-harm from 2018 to 2021 and to identify vulnerable age groups through age-stratified incidence rates.

Methods

Study design, setting and data sources

We conducted an observational study using a population-based database from the Osaka Emergency Information Research Intelligent Operation Network (ORION) system. The database is a comprehensive area-based database that is managed by the Osaka Prefectural Government. It contains a range of information on patients who have been transported by fire departments in the Osaka Prefecture, such as ambulance transport records, Utstein template for cardiopulmonary arrest, hospital selection and transport criteria, and hospital information on main diagnoses and treatment. The database covers the entire area of Osaka Prefecture, which has a population of 8.82 million and an area of 1899 km². The ORION system has been operated since January 2013, and hospital data have been collected since January 2015.²⁰ The standardised electronic form was used to collect ambulance transport records in the ORION database.²¹ EMS personnel completed the data, and it was then transmitted to the information centre at the local fire department. If there was any information missing, it was sent back to the respective EMS personnel for completion. The ORION database is a combined data set from EMS and medical institutions, aimed at examining the diagnosis and prognosis of transported patients. Non-transportation cases are excluded during data cleaning. The data, originally collected for administrative purposes, are cleaned and anonymised before distribution to researchers. Notably, no essential items in the analysed data had missing values. In Japan, universal health coverage has been the basis of the healthcare system since 1961, and the ambulance service is a public service that is provided completely free of charge.²²

EMS in Japan

The EMS system in Japan is operated by local fire departments and can be activated through a 1-1-9 call from anywhere in the country, as previously described.²¹ Each ambulance typically has a crew of three emergency providers, including at least one highly trained emergency life-saving technician. EMS personnel on the scene are responsible for selecting the appropriate hospitals for patient transport. The quality of care provided by EMS personnel in prehospital settings is overseen by local medical control councils comprising emergency physicians and area experts who conduct follow-up assessments of EMS procedures.

Population

The study enrolled all patients in the ORION database who were transported for self-harm during 2018–2021. The EMS personnel had the option to select ‘self-harm’ as the reason for transport, and the term was defined as any instance of self-poisoning or self-injury, irrespective of suicidal ideation.²³ Patients were excluded if they were transported between hospitals within 21 days, as their survival data were unknown, if their survival data were missing or if they left the hospital without being examined by a physician.

Variables

The data were gathered through the use of standardised data collection forms which recorded the following: age, sex, location of the event (eg, private residence, public place, road, workspace and others), time of the event (eg, time of day, day of week, month of year), disposition on arrival day, 21-day outcomes after admission and 21-day mortality. The primary outcome of this study was the incidence of ambulance transports for self-harm and the secondary outcome was 21-day mortality. Age was classified into eight groups: 19 years and younger, 20–29 years, 30–39 years, 40–49 years, 50–59 years, 60–69 years, 70–79 years and 80 years and older. Time of day was divided into four periods: 00:00–05:59, 06:00–11:59, 12:00–17:59 and 18:00–23:59. Day of the week was categorised as either a weekday (Monday to Friday) or weekend (Saturday or Sunday). Disposition on arrival day and 21-day outcome after admission were both classified as admission, discharge and death.

Statistical analysis

The median and IQR were used to present continuous variables, while counts and percentages were used for categorical variables. To calculate the incidence rates of ambulance transport due to self-harm per 100 000 person-years, annual population reports from Osaka Prefecture were used.²⁴ Trends for 2018, 2019, 2020 and 2021 were evaluated using the Jonckheere-Terpstra test for continuous variables and the Cochrane-Armitage test for nominal variables. To compare the incidence rates of ambulance transport due to self-harm and all-cause mortality within 21 days in 2019 through 2021 with those in 2018, we estimated unadjusted and adjusted incidence rate ratios (IRRs) with 95% CIs using a Poisson regression model with a log (population) offset term for population of Osaka Prefecture in 2019. In adjusted analyses, we included age groups, sex and month of year as covariates as they were known potential confounders in research of self-harm.^{25 26} The years 2018 and 2019 were prepandemic and should not have been affected by the pandemic. By using 2018 as a reference year and comparing it with 2019, we investigated the trend of changes before the pandemic. For the years 2020 and 2021, they were during the pandemic period, and we examined how they each changed. To identify vulnerable age groups, age-stratified IRRs were calculated for ambulance transport due to self-harm. All statistical tests were two tailed, and statistical significance was considered at p values <0.05. The R statistical software (V.3.6.2; R Foundation for Statistical Computing, Vienna, Austria) was used to perform all statistical analyses.

Patient and public involvement

Patients and the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research. We will not directly disseminate our findings to involved participants but plan to disseminate them through publication of this study.

Results

Study patients

During the study period, 11 839 emergency patients were transported due to self-harm. Of these, 10 843 patients met the eligibility criteria for this study (figure 1). There were 2593 patients in 2018; 2695 patients in 2019; 2805 patients in 2020; and 2750 patients in 2021. The incidence rate of ambulance transport for self-harm in the total population was 30.7 cases per 100 000 person-years. The annual incidence per 100 000 population was 29.4 in 2018; 30.5 in 2019; 31.8 in 2020; and 31.2 in 2021, with a significant increasing trend (p=0.013). The median age of the entire patient population was 38 years (IQR 25–53 years), with the largest age group being 20–29 years (25.0%) and the second largest being 40–49 years (17.6%). The median age tended to be younger each year at 40 years in 2018; 39 in 2019; 38 in 2020; and 36 in 2021, respectively (p=0.002). By age group, there was a statistically significant increasing trend in the groups of patients aged 19 years or younger (p<0.001) and 20–29 years (p<0.001), and a decreasing trend in the groups of patients aged 30–39 years (p=0.001), 40–49 years (p<0.001) and 60–69 years (p=0.017). Female patients were more than twice as common as male patients, comprising 69.0% and 31.0% of the patient population, respectively. The majority of self-harm patients were transported from private residences (82.6%), with the most common time of day being 18:00–23:59 (32.3%) and the most common month of the year being July (9.4%) followed by September (9.3%). The overall 21-day mortality was 16.1% with no significant difference in the 4-year trend (online supplemental table).

Figure 1.

Patient flow.

Analyses of IRR for self-harm and mortality

There were no significant differences in the incidence of ambulance transport due to self-harm in 2019 (adjusted IRR 1.007; 95% CI 0.955 to 1.063; p=0.789), 2020 (adjusted IRR 1.041; 95% CI 0.987 to 1.098; p=0.142) and 2021 (adjusted IRR 1.022; 95% CI 0.968 to 1.078; p=0.435) when compared with the numbers of ambulance transports due to self-harm in 2018 (table 1). There were no significant differences in 21-day mortality in 2019 (adjusted IRR 1.023; 95% CI 0.893 to 1.173; p=0.743), 2020 (adjusted IRR 1.019; 95% CI 0.894 to 1.163; p=0.774) and 2021 (adjusted IRR 0.988; 95% CI 0.865 to 1.129; p=0.861) compared with the 21-day mortality in 2018 (table 2).

Table 1.

Incidence rate ratios (IRR) of patients transported by ambulance due to self-harm by year

Characteristics	Unadjusted IRR	95% CI	P value	Adjusted IRR	95% CI	P value
2019 vs 2018	1.039	0.985 to 1.097	0.161	1.007	0.955 to 1.063	0.789
2020 vs 2018	1.079	1.023 to 1.138	0.005	1.041	0.987 to 1.098	0.142
2021 vs 2018	1.063	1.008 to 1.122	0.025	1.022	0.968 to 1.078	0.435

Multivariate models were adjusted for age group, sex and month.

Table 2.

Overall mortality rate ratio for all-cause mortality within 21 days among patients transported by ambulance due to self-harm from 2018 to 2021

Characteristics	Unadjusted IRR	95% CI	P value	Adjusted IRR	95% CI	P value
2019 vs 2018	0.980	0.856 to 1.123	0.772	1.023	0.893 to 1.173	0.743
2020 vs 2018	0.995	0.873 to 1.135	0.945	1.019	0.894 to 1.163	0.774
2021 vs 2018	1.018	0.891 to 1.162	0.798	0.988	0.865 to 1.129	0.861

Multivariate models adjusted for age group, sex and month.

IRR, incidence rate ratio.

IRRs by age group

Among individuals aged 20–29 years, there was no statistically significant difference in the incidence of ambulance transport due to self-harm in 2019 (adjusted IRR 1.015; 95% CI 0.907 to 1.136; p=0.792) and 2021 (adjusted IRR 1.065; 95% CI 0.956 to 1.187; p=0.253) compared with 2018. However, there was a significant increase of 11.7% in 2020 (adjusted IRR 1.117; 95% CI 1.002 to 1.245; p=0.045). There were no significant differences in incidence rates observed among other age groups (table 3).

Table 3.

Incidence rate ratios of patients with self-harm from 2018 through 2021 by age group

Age group	Frequency	Adjusted IRR	95% CI	P value
19 years and younger
2019 vs 2018	242 vs 212	1.086	0.903 to 1.307	0.383
2020 vs 2018	247 vs 212	1.077	0.896 to 1.294	0.431
2021 vs 2018	331 vs 212	1.170	0.985 to 1.393	0.075
20–29 years
2019 vs 2018	634 vs 590	1.015	0.907 to 1.136	0.792
2020 vs 2018	741 vs 590	1.117	1.002 to 1.245	0.045
2021 vs 2018	747 vs 590	1.065	0.956 to 1.187	0.253
30–39 years
2019 vs 2018	497 vs 480	1.021	0.901 to 1.158	0.742
2020 vs 2018	476 vs 480	1.069	0.942 to 1.214	0.302
2021 vs 2018	427 vs 480	0.993	0.871 to 1.132	0.918
40–49 years
2019 vs 2018	514 vs 488	0.966	0.853 to 1.094	0.583
2020 vs 2018	477 vs 488	0.963	0.848 to 1.093	0.557
2021 vs 2018	428 vs 488	0.981	0.861 to 1.117	0.771
50–59 years
2019 vs 2018	361 vs 335	1.151	0.905 to 1.220	0.514
2020 vs 2018	376 vs 335	1.088	0.938 to 1.261	0.265
2021 vs 2018	344 vs 335	1.052	0.905 to 1.223	0.509
60–69 years
2019 vs 2018	168 vs 186	0.990	0.802 to 1.222	0.927
2020 vs 2018	176 vs 186	0.956	0.777 to 1.177	0.674
2021 vs 2018	151 vs 186	0.946	0.762 to 1.174	0.618
70–79 years
2019 vs 2018	164 vs 185	0.967	0.783 to 1.193	0.754
2020 vs 2018	186 vs 185	1.015	0.826 to 1.247	0.888
2021 vs 2018	191 vs 185	0.984	0.802 to 1.207	0.875
80 years and older
2019 vs 2018	115 vs 117	0.949	0.729 to 1.235	0.698
2020 vs 2018	126 vs 117	0.925	0.717 to 1.193	0.545
2021 vs 2018	131 vs 117	0.956	0.742 to 1.232	0.726

Multivariate models were adjusted for sex.

IRR, incidence rate ratio.

Discussion

A comprehensive analysis of patient characteristics and incidence rates of ambulance transport due to self-harm from 2018 to 2021 was conducted using a population-based database. No significant difference in incidence rates of ambulance transport due to self-harm and 21-day mortality between 2019 and 2021 compared with 2018 was found. However, a statistically significant increase in the incidence rate of ambulance transport due to self-harm in the 20–29 age group was observed in 2020.

A previous study found that there was an increase in self-harm cases in 2020 despite a previous report showing that there were fewer EMS transports in Osaka in 2020 compared with 2019.¹⁸ The increase in self-harm cases in 2020 in our study may be attributed to the impact of the COVID-19 pandemic and the subsequent social restrictions, which may have negatively affected the mental health of young people. A systematic review of surveys conducted with the general public also revealed that the COVID-19 pandemic resulted in anxiety, depression and psychological stress.²⁷ Additionally, young people may be more susceptible to the negative effects of false information.²⁸ A previous report using data from the Ministry of Health, Labour and Welfare in Japan reported that there was no increase in the suicide rate among children due to school closures and other effects.²⁹ Our study suggested that the age group of 20–29 years could be more vulnerable to mental health problems brought about by the COVID-19 pandemic and the related environmental changes than other age groups. Encouraging timely access to mental health services and providing financial and social support may help decrease the incidence of self-harm, according to previous studies.^{30 31} Although the incidence rate in the 20–29 age group increased in 2020 compared with 2018, the incidence rate in 2021 was not statistically different from 2018. It is possible that the 20–29 age group might have already adapted to the changes in their environment in 2021. Further study is needed to assess the reasons of our findings.

The study provides valuable insights on vulnerable age groups prone to self-harm, guiding policymakers in targeting enhanced mental health support through tailored interventions. Understanding ambulance transport patterns informs policymakers and facilitates the formulation of policies to improve care patients with self-harm. Additionally, the study emphasises the need to integrate mental health into broader public health strategies, promoting mental health components in various health programmes. Policymakers can leverage these findings to implement evidence-based interventions and enhance mental health support systems for vulnerable populations. Clinically, it is essential for workers in the emergency departments and EMS to be well prepared in their knowledge of mental health, especially during a pandemic. Measures such as reinforcing mental healthcare in the emergency departments and providing psychiatric care at all times, including during the night, should be considered.

There are several limitations in our study. First, our database did not provide information on the motivation for self-harm, including whether it was non-suicidal or suicidal. This makes it difficult to draw any conclusions based on these factors. Second, in cases where there was no clear evidence of self-harm at the scene, patients with severe trauma due to a fall from height may have been misclassified as accidental injuries. Third, the ORION database did not always contain diagnoses related to self-harm, thereby precluding the determination of the specific method used, such as self-poisoning or self-injury. In addition, there were no available data on provided care for self-harm by EMS other than cardiopulmonary resuscitation in the present data, and therefore, it could not be analysed. The data set analysed was prepared for the purpose of examining the diagnosis and prognosis of transported patients. Although approximately 20% of emergency calls are for non-transportation for various reasons in Osaka Prefecture, non-transported cases were not included in the data set, making an analysis including non-transported cases a topic for future investigation.²⁰ Furthermore, we were unable to fully consider long-term trends in our study. However, it is important to note that the years 2018 and 2019 were prepandemic, and we observed no statistically significant difference during that period. Finally, our study only included patients in Osaka Prefecture, so our inferences may not be generalisable to other areas with different cultural backgrounds, medical systems and policies. Despite these limitations, our population-based study provides important information that can be used to improve mental healthcare policies.

Conclusions

Using the population-based database in Osaka Prefecture, we studied patients transported by ambulance due to self-harm from 2018 through 2021 and did not detect a significant difference in the incidence rates of ambulance transport due to self-harm and 21-day mortality. Nevertheless, we observed an increase in the incidence rate among the 20–29 age group in 2020, which was the largest age group. The study provides important information about vulnerable age groups susceptible to self-harm, guiding policymakers in targeting enhanced mental health support through tailored interventions. Additionally, it highlights the essential need for emergency department and EMS workers to be well prepared in addressing mental health concerns effectively.

Data availability statement

Data are available upon reasonable request. The data set for the current study belongs to the Osaka Prefectural Government and The Working Group to Analyze the Emergency Medical Care System in Osaka Prefecture. Data are only available on request to the Osaka Prefectural Government, and access requires appropriate ethical and governance clearances regarding use.

Ethics statements

Patient consent for publication

Not applicable.

Ethics approval

The Institutional Ethics Committee of Osaka University Graduate School of Medicine approved this study and waived the need for informed consent because all analyses used anonymous data (approval number 15003).