Stressful Life Events Moderate the Relationship Between Changes in Symptom Severity and Health-related Quality of Life in Patients With Irritable Bowel Syndrome

OBJECTIVES: The relationship between changes in symptom severity and health-related quality of life (HRQOL), which may be impacted by stressful life events, in irritable bowel syndrome (IBS), is unclear. Therefore, we investigated the relationship between changes in symptom severity and HRQOL and examined the moderating role of stressful life events in patients with IBS. METHODS: This study is part of a cohort follow-up study on psychological factors in patients with IBS in tertiary care, and it included 158 patients. In addition to symptom severity and HRQOL, stressful life events were assessed by the Social Readjustment Rating Scale (SRRS). The relationship between symptom severity and HRQOL and the moderating role of stressful life events (in the 12 mo before the follow-up assessment) were analyzed. RESULTS: The majority of participants had moderate levels of stressful life events (41.8%), followed by those who had mild levels (39.2%) and severe levels (19.0%) of stressful life events. Symptom severity could predict HRQOL, and the relationship between symptom severity and HRQOL was affected by the level of stressful life events. Compared with mild levels of stressful life events, a severe level of stressful life events significantly affected the relationship between changes in symptom severity and HRQOL (Z=-3.048, P<0.01). A similar result was found when comparing moderate and severe levels of stressful life events (Z=-1.810, P<0.10). CONCLUSIONS: The study demonstrated that symptom severity predicted HRQOL during the progression of IBS and that stressful life events moderated the impact of symptom severity on HRQOL. The more stressful life events an IBS patient experiences, the less predictable the relationship is between changes in symptom severity and HRQOL.