Abstract
Background and Aim
Both intestinal symptoms and comorbidities exist in irritable bowel syndrome (IBS) patients and influence their quality of life (QOL). More research is needed to determine how these variables impact the QOL of IBS patients. This study aimed to determine which specific factors had a higher influence on QOL and to further compare the effects of intestinal symptoms and comorbidities on QOL.
Methods
IBS patients were recruited from six tertiary hospitals in different regions of China. QOL, gastrointestinal symptoms, and comorbidities were assessed by different scales. Correlation analysis, multiple linear regression, and mediation model were used for statistics.
Results
Four hundred fifty‐three IBS patients (39.7% women, mean age 45 years) were included and no significant differences in QOL were found across demographic characteristics. Abnormal defecation (r = −0.398), fatigue (r = −0.266), and weakness (r = −0.286) were found to show higher correlation with QOL. More than 40% of IBS patients were found to suffer from varying degrees of anxiety or depression, and anxiety (r = −0.564) and depression (r = −0.411) were significantly negatively correlated with QOL (P < 0.001). Psychological factors showed the strongest impact (β′ = −0.451) and play a strong mediating role in the impact of physiological symptoms on QOL. Anxiety was found to be the strongest factor (β′ = −0.421).
Conclusion
Compared with other symptoms, psychological symptoms, particularly anxiety, are more common and have a more negative influence on QOL. The QOL of IBS patients is also significantly impacted by abnormal defecation, abdominal distension, and systemic extraintestinal somatic symptoms. In the treatment of IBS patients with unhealthy mental status, psychotherapy might be prioritized.
Keywords: extraintestinal somatic symptoms, gastrointestinal symptoms, irritable bowel syndrome, psychological symptoms, quality of life
A multicenter cross‐sectional study conducted in China compared gastrointestinal symptoms, extraintestinal somatic symptoms, and psychiatric symptoms in patients with irritable bowel syndrome (IBS). The study revealed that psychiatric symptoms had a more significant impact on the quality of life of IBS patients.
Introduction
Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease, with a high population prevalence of about 9% worldwide. 1 It is a complex physical and mental disease with symptoms mainly including fluctuating abdominal pain or discomfort, abdominal distension, alteration in defecation frequency, and stool form as well as some psychiatric symptoms or overall somatic symptoms, resulting in a substantial medical and financial burden. 2
Clinical intervention can usually temporarily relieve the GI symptoms of IBS patients, but it is difficult to cure it completely in the clinical diagnosis and treatment process because of its complex and underlying pathogenesis (increased epithelial cell permeability, biological dysregulation, inflammation, visceral hypersensitivity, epigenetics and genetics, and changes in brain‐gut interaction) 3 and the heterogeneity of patients. The course of IBS for many years has caused a huge burden on the lives of patients and more or less affected the quality of life (QOL) of patients.
The ultimate goal of daily management of IBS patients is to improve the QOL, which is also the essential purpose of curing disease. In recent years, more and more attention has been paid to the comorbidities of IBS patients, which have been proven to be risk factors affecting the QOL of IBS, suggesting that IBS should not be treated solely around GI symptoms. 4 , 5
It is necessary to make a specific multifaceted disease management (lifestyle changes, dietary changes, probiotics, drug therapy, psychotherapy) 6 to improve the QOL of IBS patients. To provide a reference for optimizing the daily management of patients with IBS, we focus on the QOL rather than just limited to the relief of symptoms, by analyzing the impact of GI symptoms, physical comorbidities, and mental status on the different dimensions of the QOL, to find out the relatively more important influencing factors.
Methods
Study setting
A cross‐sectional study in the GI department of six tertiary hospitals was conducted between November 2016 and October 2017. The six tertiary hospitals are from different orientations in China, including Xi'an in the northwest, Guiyang in the southwest, Wuhan in the central region, Dalian in the northeast, Nanning in the South, and Hangzhou in the east, which makes the sample geographically representative in China.
This study has been approved by the Institutional Ethical Review Committee of Huazhong University of Science and Technology.
Enrollment of subjects
Consecutive GI outpatients diagnosed with suspected IBS by an outpatient physician were recruited. A series of questions including basic personal information, history of disease and surgery, and results of colonoscopy were asked face‐to‐face to provide a reference for inclusion or exclusion after informed consent was obtained. Patients over 18 years of age, at least 3 months of course, no red flag signs of digestive tract, and negative results of colonoscopy within 2 years would be included. Patients would be excluded if they have abdominal surgery (excluding appendectomy), are pregnant, or have a communication barrier.
Questionnaires
During a structured medical interview, we collected demographic information including age and gender, marital status, level of education, and income as well as health‐related factors including body mass index, history of gastrointestinal infections, and whether they were smokers or alcohol users. In addition, we asked the patients about the abdominal symptoms and defecation‐related symptoms according to Rome criteria to screen patients who were positive for Rome III criteria (Table 1). 7 , 8 More questionnaires for data collection would be administered to patients who were finally enrolled, including demographic information, IBS diagnostic questions, Gastrointestinal Symptom Rating Scale (GSRS), 9 Hospital Anxiety and Depression Scale (HADS), 10 , 11 overall somatic symptom questions, and Irritable bowel syndrome quality of life (IBS‐QOL) measurement 12 , 13 , 14 (Fig. 1).
Table 1.
Diagnostic criteria
| Rome III criteria |
Continuous or recurrent abdominal pain or discomfort at least 3 days per month in past 3 months with at least two of the following:
|
| Rome III criteria—IBS subtype definition |
|
IBS‐C: Hard or lumpy stool ≥25% and loose (mushy) or watery stool <25% of bowel movements. IBS‐D: Loose (mushy) or watery stool ≥25% and hard or lumpy stool <25% of bowel movements. IBS‐M: Hard or lumpy stool ≥25% and loose (mushy) or watery stool ≥25% of bowel movements. IBS‐U: Insufficient abnormality of stool consistency to meet criteria for IBS‐C, D, or M |
IBS, irritable bowel syndrome; IBS‐C, irritable bowel syndrome‐constipation; IBS‐D, irritable bowel syndrome‐diarrhea; IBS‐M, irritable bowel syndrome‐mixed; IBS‐U, irritable bowel syndrome‐unspecified.
Figure 1.
Flowchart of irritable bowel syndrome patients selection and investigation.
Gastrointestinal Symptom Rating Scale
Patients' gastrointestinal symptoms were measured using the GSRS. The scores range for each item from 1 to 7. The higher scores indicated more troubling symptoms. Each item on the scale was evaluated and divided into five symptom dimensions, including abdominal pain, abdominal distention, borborygmus, increased flatus, and abnormal defecation. Items regarding upper GI symptoms were also included in the calculations, including hunger pain, nausea, eructation, acid reflux, and heartburn.
Hospital Anxiety and Depression Scale
Patients' psychological status including anxiety and depression was measured by the HADS. Scores of two subscales of HADS (depression subscale and anxiety subscale) were calculated separately to evaluate the degree of anxiety and depression of IBS patients. The scores range for both subscales were from 0 to 21. Patients were divided into three groups based on the score, 0–7 as healthy, 8–10 as suspected, and 11–21 as definite. The sum of anxiety and depression scores was used to represent the severity of psychological symptoms in patients.
Extraintestinal somatic symptoms
A broad range of extraintestinal somatic symptoms was taken into account. The presence or absence of extraintestinal somatic symptoms including headache, neck and shoulder pain, backache, muscle and joint pain, morning stiffness, insomnia, fatigue, asthma symptoms, weakness, dizziness, intolerance of cold and hot, palpitation, chest tightness, pollakiuria, and dyspareunia were collected. 15
Irritable bowel syndrome‐quality of life
The QOL was measured using the Chinese version of IBS‐QOL. Thirty‐four items were asked and divided into eight sub‐dimensions including dysphoria, interference with activity, body image, health worry, food avoidance, social reaction, sexual, and relationships. Scores of the total dimension and eight sub‐dimensions were calculated and ranged from 0 to 100.
Statistics
Data were analyzed using IBM SPSS Statistics 26.0. Kolmogorov–Smirnov test was used to test the normality. Median and interquartile range was used for distributed non‐normally continuous measures, and group comparisons were performed using Wilcoxon rank sum tests. Categorical data are presented as numbers and percentages, and compared using the chi‐square test. Spearman correlation coefficients and partial correlation coefficients were calculated for correlation analysis of non‐normal continuous data and significance was tested.
Univariate analysis was used to screen for significant variables and provide the basis for the inclusion of variables in multiple linear regression. Multiple linear regression was used to examine relationships between QOL and variables of different dimensions, while controlling for age, gender, smoking, and drinking history. 16 , 17 Standardized coefficients were presented to compare the impact of predictors. Mediation effects were calculated to assess the mediating role of different symptoms in the impact of physical symptoms or psychiatric symptoms on IBS‐QOL. Significance was set at P < 0.05.
Results
Six hundred and forty patients participated in this research. Among the 640 patients who met the inclusion criteria and were interviewed, 453 were included in the analysis after re‐evaluation and 187 were excluded (64 did not complete the questionnaire, 16 had no corresponding paper record, 4 were under the age of 18, and 103 had a history of intestinal surgery other than appendectomy).
Subjects included 453 IBS patients (39.7% women, mean age 45 years, 10.2% IBS‐C, 62.5% IBS‐D, 2.0% IBS‐M, and 25.4% IBS‐U). Median quality‐of‐life scores range from 76.5 to 89.0. There is no statistically significant difference in the QOL in different groups of age, gender, marital status, education level, income level, body mass index, history of gastrointestinal infection, smoking, and drinking (Table 2).
Table 2.
Demographic characteristics and IBS‐QOL score in IBS patients
| Characteristic | n/N (%) | IBS‐QOL score, median (IQR) | P |
|---|---|---|---|
| Age, years | 0.057 | ||
| 18 ~ 30 | 76/452 (16.8) | 77.2 (26.1) | |
| 31 ~ 45 | 169/452 (37.4) | 77.7 (26.8) | |
| 46 ~ 60 | 138/452 (30.5) | 85.30 (20.0) | |
| >60 | 69/452 (15.3) | 83.8 (25.0) | |
| Gender | 0.265 | ||
| Male | 273/453 (60.3) | 83.8 (26.1) | |
| Female | 180/453 (39.7) | 80.2 (24.5) | |
| BMI, kg/m2 | 0.310 | ||
| <18 | 21/450 (4.7) | 87.5 (26.5) | |
| 18–24 | 271/450 (60.2) | 82.4 (23.5) | |
| >24 | 158/450 (35.1) | 84.2 (25.9) | |
| Educational level | 0.090 | ||
| Primary | 64/447 (14.3) | 87.1 (23.4) | |
| Secondary | 208/447 (46.5) | 83.8 (27.2) | |
| High | 175/447 (39.1) | 80.9 (24.3) | |
| Marital status | 0.187 | ||
| Married | 393/448 (87.7) | 83.1 (24.3) | |
| Single | 50/448 (11.2) | 76.5 (29.2) | |
| Divorced or widow | 5/448 (1.1) | 88.2 (25.4) | |
| Income level | 0.196 | ||
| Low | 73/422 (17.3) | 79.4 (27.2) | |
| Medium | 212/422 (50.2) | 83.1 (23.4) | |
| High | 137/422 (32.5) | 80.9 (25.4) | |
| Smoking | 0.083 | ||
| Yes | 125/451 (27.7) | 85.3 (27.2) | |
| No | 326/451 (72.3) | 82.0 (25.0) | |
| Drinking | 0.289 | ||
| Yes | 124/451 (27.5) | 84.2 (26.5) | |
| No | 327/451 (72.5) | 82.4 (25.0) | |
| History of gastrointestinal infections | 0.419 | ||
| Yes | 109/430 (25.3) | 80.9 (24.3) | |
| No | 321/430 (74.7) | 83.8 (26.5) | |
| Type of IBS | 0.164 | ||
| IBS‐C | 46/453 (10.2) | 84.2 (20.2) | |
| IBS‐D | 283/453 (62.5) | 80.9 (25.0) | |
| IBS‐M | 9/453 (2.0) | 89.0 (23.2) | |
| IBS‐U | 115/453 (25.4) | 85.3 (24.3) | |
Frequency (percentage), median values (inter‐quartile range) and P‐values are shown.
BMI, body mass index; IBS, irritable bowel syndrome; IBS‐C, irritable bowel syndrome‐constipation; IBS‐D, irritable bowel syndrome‐diarrhea; IBS‐M, irritable bowel syndrome‐mixed; IBS‐QOL, irritable bowel syndrome quality of life measurement; IBS‐U, irritable bowel syndrome‐unspecified; IQR, inter‐quartile range.
GI symptoms and IBS‐QOL
In the heatmap of partial correlation coefficients (Fig. 2), almost all GI symptoms show a significant and negative association with QOL as well as its sub‐dimensions, only a few symptoms especially those related to constipation (decreased bowel movements and hard stools) and heartburn had no significant correlation with a few sub‐dimensions of QOL. However, the absolute value of partial correlation coefficients of GI symptoms is not high, which is less than 0.3 except for endless bowel movements (−0.314 with total score, −0.308 with dysphoria). Compared with other GI symptoms, abdominal distention, urgency of defecation, and endless bowel movements show stronger correlations with QOL and its sub‐dimensions.
Figure 2.
Heatmap of Spearman correlation coefficients between the dimensions of irritable bowel syndrome quality of life and intestinal symptoms. Bolded terms indicate that the factor is statistically significant.
HADS and IBS‐QOL
More than 40% of the IBS patients had different degrees of anxiety or depression. The proportion of patients with both anxiety and depression (22.30%) was higher than that of patients with anxiety (16.11%) or depression (4.64%) alone (Fig. 3). Scores of QOL in different sub‐dimensions among groups are presented (Table 3). There were significant differences in each sub‐dimension and total score of QOL among the three groups (0–7 as healthy case, 8–10 as suspected case, and 11–21 as definite case) in both HADS‐A and HADS‐D. Spearman correlation coefficients between IBS‐QOL and anxiety score (r = −0.564) or depression score (r = −0.411) show a significant negative correlation.
Figure 3.
Pie chart of prevalence of anxiety and depression in irritable bowel syndrome patients. Only those patients with a Hospital Anxiety and Depression Scale (HADS) score less than 8 were defined as healthy, and those with a HADS score more than 7 were considered to be anxious or depressed.
Table 3.
IBS‐QOL score in IBS patients with different levels of anxiety and depression
| HADS score | IBS‐QOL score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| IBS‐QOL | |||||||||
| Median (IQR) | Total score | Dysphoria | Interference with activity | Body image | Health worry | Food avoidance | Social reaction | Sexual | Relationships |
| Anxiety score | |||||||||
| 0–7 | 88.24 (16.18) | 87.50 (21.88) | 89.29 (17.86) | 93.75 (12.50) | 83.33 (33.33) | 75.00 (33.33) | 100.00 (12.50) | 100.00 (0.00) | 91.67 (16.67) |
| 8–10 | 78.68 (21.32) | 75.00 (28.13) | 75.00 (25.00) | 87.50 (25.00) | 66.67 (33.33) | 66.67 (33.33) | 81.25 (25.00) | 100.00 (12.50) | 83.33 (25.00) |
| 11–21 | 58.09 (28.68) | 56.25 (31.25) | 57.14 (35.71) | 68.75 (25.00) | 41.67 (33.33) | 58.33 (41.67) | 68.75 (31.25) | 87.50 (37.50) | 66.67 (33.33) |
| P | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
| Spearman R | −0.564*** | −0.539*** | −0.531*** | −0.468*** | −0.524*** | −0.324*** | −0.480*** | −0.224*** | −0.496*** |
| Depression score | |||||||||
| 0–7 | 86.76 (19.85) | 84.38 (25.00) | 85.71 (21.43) | 93.75 (12.50) | 75.00 (33.33) | 75.00 (41.67) | 93.75 (18.75) | 100.00 (12.50) | 91.67 (16.67) |
| 8–10 | 75.00 (24.63) | 71.88 (26.56) | 71.43 (26.79) | 81.25 (25.00) | 66.67 (41.67) | 66.67 (37.50) | 81.25 (25.00) | 100.00 (12.50) | 83.33 (25.00) |
| 11–21 | 67.65 (29.78) | 62.50 (35.94) | 64.29 (37.50) | 75.00 (25.00) | 50.00 (29.17) | 66.67 (29.17) | 75.00 (40.63) | 100.00 (37.50) | 75.00 (25.00) |
| P | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.01 | <0.001 | <0.01 | <0.001 |
| Spearman R | −0.411*** | −0.393*** | −0.393*** | −0.362*** | −0.349*** | −0.222*** | −0.392*** | −0.186*** | −0.400*** |
P < 0.001.
Median values (inter‐quartile range), P‐values, and Spearman correlation coefficients are shown.
HADS, hospital anxiety and depression scale; IBS‐QOL, irritable bowel syndrome quality of life measurement; IQR, inter‐quartile range; Spearman R, Spearman correlation coefficients.
Extraintestinal somatic symptoms and IBS‐QOL
Heatmap of Spearman correlation coefficients shows that all somatic symptoms have a significant but weak correlation (the absolute value of coefficient is less than 0.3) with QOL. Fatigue, weakness, dyspareunia, and intolerance of cold and hot show a relatively stronger negative correlation with QOL and part of sub‐dimensions than other extraintestinal symptoms (Figure S1).
In addition, a negative linear trend with P < 0.001 was found in the scatter diagram with a fitted regression line between the quantity of extraintestinal somatic symptoms and IBS‐QOL (Figure S2).
IBS‐QOL with different status of comorbidities
The score of IBS‐QOL in patients with both psychological disorders and extraintestinal somatic syndrome (group C) was found significantly lower than that in patients with only one (group B) or no comorbidity (group A) in all dimensions, and statistical differences were found (P < 0.001). No significant difference was found between group A and group B (Table 4).
Table 4.
Quality of life in IBS patients with different status of comorbidities
| IBS‐QOL | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| IBS‐QOL | |||||||||
| Median (IQR) | Total score | Dysphoria | Interference with activity | Body image | Health worry | Food avoidance | Social reaction | Sexual | Relationships |
| Group A (n = 41) | 86.03 (19.85) | 87.50 (25.00) | 85.71 (25.00) | 100.00 (12.50) | 83.33 (37.50) | 75.00 (33.33) | 100.00 (18.75) | 100.00 (0.00) | 91.67 (16.67) |
| Group B (n = 325) | 85.29 (19.11) | 84.38 (25.00) | 85.71 (21.43) | 93.75 (18.75) | 75.00 (33.33) | 75.00 (41.67) | 93.75 (18.75) | 100.00 (12.50) | 91.67 (16.67) |
| Group C (n = 87) | 61.77 (31.62) | 59.38 (37.50) | 60.71 (35.71) | 75.00 (25.00) | 41.67 (41.67) | 66.67 (33.33) | 68.75 (37.50) | 100.00 (37.50) | 75.00 (25.00) |
| P | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
| Group comparison | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C | A > C, B > C |
Note: Patients with one or more parenteral somatic symptoms were classified as Patients with parenteral somatic syndrome. Patients with anxiety or depression were classified as Patients with psychological illness. Group A = Patients without psychological illness or parenteral somatic syndrome. Group B = Patients with psychological illness or parenteral somatic syndrome. Group C = Patients with both psychological illness and parenteral somatic syndrome.
IBS‐QOL, irritable bowel syndrome quality of life measurement; IQR, inter‐quartile range.
Multiple linear regression in IBS‐QOL
In Model 1 (Table S1), psychological symptom and GI symptom were shown to be significant risk factors for all aspects of QOL (P < 0.001), with psychological symptoms (β′ = −0.451) having a stronger effect than GI symptoms (β′ = −0.271) on total score of IBS‐QOL. Extraintestinal somatic symptom was found to have a significant and relatively weak effect on IBS‐QOL only in two sub‐dimensions, body image (P = 0.003) and social reaction (P = 0.001). In general, extraintestinal somatic symptoms had less impact on IBS‐QOL than psychological symptoms and GI symptoms.
In Model 2 (Table S2), for total score of IBS‐QOL, anxiety (β = −1.640), morning stiffness (β = −4.528), intolerance of cold and hot (β = −4.088), dyspareunia (β = −6.214), abdominal distention (β = −1.436), urgency of defecation (β = −1.048), and endless bowel movements (β = −1.021) were found significant in multiple‐factor analysis. Other factors including depression, back pain, weakness, dyspareunia, borborygmus, increased bowel movements, and loose stools were found to be significant in some sub‐dimensions.
A heatmap of standardized regression coefficients was shown to compare the effects of different factors (Figure S3). By comparing the standardized coefficients, we found that anxiety shows a far stronger impact than any other factors whether in the total dimension or other sub‐dimensions (except sexual).
Stepwise regression analysis was carried out, and only seven risk factors were included in the results. Pareto diagram was drawn according to their standardized coefficients. The results also showed that anxiety, bloating, urgency of defecation, and intolerance of cold and heat were important factors affecting the QOL, among which the contribution of anxiety was much higher than the other three symptoms (Figure S4).
The mediating effect of three dimensions on IBS‐QOL
Psychological factors were found to be important mediators of physical factors affecting IBS‐QOL (P < 0.001) in all sub‐dimensions. Compared with GI symptom, extraintestinal somatic symptom is found to affect the QOL more through psychological effects. For GI symptoms, the ratio of psychological mediating to the total effect on IBS‐QOL fluctuates between approximately 20% and 40%. While the ratio for extraintestinal somatic symptoms fluctuates between approximately 30% and 50% (Figure S5).
In another mediating effect model, we found that physical symptoms also mediated the effect of psychological symptoms on QOL (Figure S6). The mediating effect ratio of GI symptoms was found to be stronger than that of extraintestinal somatic symptoms in its effect on overall QOL (12.42% vs 4.98%). The mediating effect of GI symptom was present in each sub‐dimension of IBS‐QOL, while the mediating effect of extraintestinal somatic symptom was present only in three sub‐dimensions including body image (M = −0.08), social reaction (M = −0.11), and sexual (M = −0.09).
Discussion
Our study found that in terms of GI symptoms, urgency of defecation and endless bowel movements seem to be more troubling to patients than any other abnormal bowel habits and mainly affect the sub‐dimensions of dysphoria, interference with activity, and health worry. In addition, interference with activity, health worries, and dysphoria indeed show a relatively strong association with these feelings of abnormal defecation. We speculate that the mobility inconvenience and psychological burden caused by abnormal defecation sensation may be the root cause of the deterioration of the patient's QOL. To our surprise, abdominal pain did not appear to have a relatively strong effect on QOL compared with other bowel symptoms. In contrast, abdominal distension was found to be more associated with QOL and affect QOL more than abdominal pain, although previous studies have shown that patients with abdominal discomfort have similar intestinal symptoms and psychosocial characteristics to those with abdominal pain. 18 Considering that the study population is Rome III positive and IBS‐D accounts for a large proportion, and the pain can be relieved after defecation in a large majority of the population, we speculated that patients may enhance their cognitive ability of abdominal pain in the process of relieving pain by defecation, thus reducing the psychological pressure and bad feelings caused by this symptom. 19
It is worthy to note that although we did not find significant differences in QOL among the subtypes of IBS, symptoms related to diarrhea were found to have stronger and more significant negative associations with QOL than symptoms related to constipation. This suggests that the QOL of patients with diarrhea may be more susceptible to the effects of abnormal bowel movements.
As for the mental aspect, we found that the mental health of IBS patients was not optimistic, in which case more than 40% of the patients had more or less anxiety or depression, and the vast majority of these mentally ill people have anxiety problems.
Some studies have shown that psychological factors have various influences on IBS. 20 , 21 Anxiety and depression have been proved by many studies to be important risk factors leading to the onset of IBS and the destruction of QOL. 22 , 23 , 24 This study reproduces previous findings and finds anxiety and depression have a relatively high negative correlation with QOL than physical symptoms. In addition, anxiety showed a stronger negative association with QOL than depression, possibly because anxiety worsens disease symptoms or alters patients' cognition. 5 , 25 The specific reasons are not clear, but there is no doubt that anxiety is more worthy of attention, which suggests that for patients with both anxiety and depression, relieving anxiety may be more effective in improving the QOL.
Extraintestinal somatic symptoms have long been common in patients with IBS, and their impact on IBS is also of concern. 15 , 26 Our study found that the QOL of IBS patients decreases with the increase in extraintestinal somatic symptoms. Almost all of the extraintestinal somatic symptoms showed weak but significant negative correlations with IBS‐QOL, in which fatigue and weakness had a stronger negative correlation, and were mainly manifested in the three sub‐dimensions of dysphoria, body image, and social reaction. Among the extraintestinal symptoms, local somatic pain, such as headache, neck and shoulder pain, back pain, and joint muscle pain had a relatively weak negative correlation with QOL. Compared with these local somatic discomforts, weakness and fatigue are more mental and show a relatively high negative correlation with IBS‐QOL, which suggests that systemic bad feelings of wholeness are more closely related to life quality and deserve more attention compared with local somatic symptoms.
We sought to find the difference in QOL among patients with different levels of comorbidities and found that the difference was only observed according to whether patients had both psychological and extraintestinal comorbidities. This further confirms our belief that the QOL of IBS patients deteriorates further with increasing severity of comorbidities. There was an additional finding that patients with only one type of comorbidity did not show a significant difference in IBS‐QOL between the group with no comorbidity, which suggests that the QOL will not be significantly affected until the comorbidity has developed to a certain extent.
We included overall symptom measures and some meaningful specific symptoms of three dimensions (GI symptoms, extraintestinal symptoms, and psychiatric symptoms) in multiple linear regressions and analyzed QOL and its sub‐dimensions separately. To our surprise, we found that psychological problems had a significant impact on IBS‐QOL than GI symptoms by comparing the standardized coefficients both in Model 1 and Model 2, in which case, anxiety had a significant impact on QOL than others. Previous research results only proved that anxiety and GI symptoms together affect the QOL of IBS‐D. 22 Our findings are consistent with previous studies and suggest that in the daily management of irritable bowel, psychotherapy plays a more important role. 27 , 28 The study also found that although there were significant differences in IBS‐QOL between patients with different levels of anxiety or depression, the effect of depression became insignificant when anxiety and depression were included in the model together. Given the prevalence of anxiety among mentally ill people, we speculate that because patients with anxiety tend to have concomitant depression, this reinforces the role of depression in the univariate analysis. We speculate that anxiety may be the main factor of psychotherapy that affects the QOL of patients with IBS.
In addition, apart from weakness and fatigue, some other important extraintestinal symptoms that were found to be significant in multivariate analysis were identified in the regression model including morning stiffness, intolerance of cold and hot, and dyspareunia. In terms of GI symptoms, abdominal distension and the abnormal bowel evacuation habit including the urgency of defecation and endless bowel movements had a significant impact on IBS‐QOL and its sub‐dimensions, which was consistent with the results of the correlation analysis.
Based on the significant differences in the above univariate analysis and the results of the impact of the severity of the three types of symptoms on QOL in the multiple regression model, we analyzed the mediating effect of the three types of symptoms to further explore the influence of psychological factors on QOL We found that the effect of psychological symptoms on the QOL is complex, it not only has a direct strong effect on the QOL but also plays an important mediating role in the effect of physical symptoms on the QOL, especially for extraintestinal somatic symptoms. At the same time, it also indirectly affects the QOL of patients through physical symptoms. Psychological problems caused by GI symptoms accounted for about 30% of the total effect of GI symptoms on IBS‐QOL and fluctuated from 20% to 40% with different sub‐dimensions. The mediating effect of psychological symptoms in extraintestinal symptoms was greater, accounting for 30–50% of the total effect, and even exceeded the direct effect of extraintestinal symptoms on QOL in interference with activity and relationship. We hypothesize that some of the extraintestinal symptoms may give the patient the false impression that they are suffering from other diseases and lead to worse negative emotions such as anxiety. We also believe that psychological symptoms can exacerbate physical symptoms and affect QOL. We in turn calculated the mediating effect of physical symptoms and found that GI symptoms accounted for only about 12% of the total effect, while extraintestinal symptoms accounted for only 5% of the total effect, which was mainly reflected in body image, social reaction, and relationships.
These suggest that psychological symptoms and physical symptoms mediate each other in their influence on IBS‐QOL, and psychological symptoms play a significant mediating effect.
Limitation
Although our research objects come from different regions of China, they are limited to China. Considering the taboo of sex in Chinese culture, the research conclusion of the sexual life dimension may also be biased. In addition, the samples were only from tertiary hospitals, and some patients with mild symptoms may choose to seek medical treatment in primary medical institutions, while patients in tertiary hospitals may have more serious health worries and anxiety, which may have a certain impact on the study results. In addition, there is a dysphoria sub‐dimension in the QOL, which may exaggerate the influence of anxiety, but correlation analysis finds that the collinearity of anxiety and dysphoria dimension is not high, and the results show that the standardized coefficient of anxiety is much higher than other factors. Anxiety is indeed the most critical factor affecting the QOL, no matter whether it is included in the IBS‐QOL measures.
In conclusion, although much research has been conducted on QOL in patients with IBS, the magnitude of anxiety's impact on IBS‐QOL and how psychological factor affects it (whether it is primarily through aggravating physical symptoms in and out of the gut or directly on patients' perceptions of QOL) remains to be further studied. That is what we are trying to find out.
During clinical diagnosis and treatment, only a small part of IBS patients choose to seek medical treatment and receive relevant psychological counseling in addition to relieving intestinal symptoms. Our study found that the impact of anxiety on the QOL of patients is much higher than GI symptoms, which suggests that psychological factors may affect the health‐related QOL of IBS patients more than the gut itself if the patients have a bad mental status. In recent years, with further research on the comorbidity of irritable bowel, the integrated management and treatment of irritable bowel have been emphasized. 6 , 29 Psychological factors such as anxiety depression and extraintestinal somatic symptoms have also attracted more and more attention. Considering the significant influence of anxiety and other mental factors on the QOL of IBS patients, we believe that psychiatric evaluation of irritable bowel patients is very necessary for clinical diagnosis and treatment. We also believe that psychotherapy for IBS should be a necessary intervention for these IBS patients with unhealthy inner moods.
In addition, the treatment of intestinal symptoms should focus more on improving defecation, while systemic extraintestinal symptoms such as fatigue, weakness, and intolerance of cold and hot also deserve the necessary attention.
Supporting information
Appendix S1. Supporting information.
Appendix S2. Supporting information.
Acknowledgments
This study was supported by the following funds: (1) Application of intestinal virus in the diagnosis and prognosis of COVID‐19 (number: 2020FCA014). (2) Study of the effect of COVID‐19 intestinal damage on coagulation function and the regulatory mechanism mediated by intestinal microecology (number: 2020BHB017).
Xiaotian Xie and Jing He contributed equally to this paper.
Declaration of conflict of interest: The authors declare that they have no competing interests.
Author contribution: All authors conceived and designed the study. They all participated in the data collection work of their hospitals. Xiaotian Xie, Jing He, Shu Xu, and Zhiyue Xu performed the data analysis and Xiaotian Xie wrote the paper. Tao Bai and Xiaohua Hou reviewed and revised the manuscript. Disagreements were arbitrated by Xiaohua Hou. All the authors have read and approved the final manuscript.
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Supplementary Materials
Appendix S1. Supporting information.
Appendix S2. Supporting information.