Background: The irritable bowel syndrome (IBS) may lead to considerable impairment of health-related quality of life and high health care costs. It is not clear whether these poor outcomes directly result from severe bowel symptoms or reflect a coexisting psychiatric disorder.
Objective: To determine whether bowel symptom severity and psychological symptoms directly influence health-related quality of life and health care costs.
Design: Cross-sectional survey.
Setting: Secondary and tertiary gastroenterology clinics.
Patients: 257 patients with severe IBS who did not respond to usual treatments and were recruited for a trial of psychological treatment.
Measurements: Predictors were abdominal pain, entries in a diary of 10 IBS symptoms, and measures of psychological symptoms. Outcomes were inability to work, health-related quality of life (measured by Medical Outcomes Survey 36-item short-form questionnaire [SF-36] physical component summary scores), and health care and productivity costs. Predictor and outcome measures were compared by using multiple regression and logistic regression analyses.
Results: Abdominal pain occurred on average 24 days per month and activities were restricted on 145 days of the previous 12 months. The mean (±SD) Hamilton depression score was 11.3 ± 6.1. The SF-36 physical component summary score was low (37.7 ± 10.6), and the patients had incurred high health care costs ($1743 ± $2263) over the previous year. Global severity and somatization scores on the Symptom Checklist 90 Revised, abdominal pain, and Hamilton depression scores independently contributed to the physical component score of the SF-36 (adjusted R2 = 35.2%), but only psychological scores were associated with disability due to ill health. These variables did not accurately predict health care or other costs (adjusted R2 = 9.3%). History of sexual abuse was not an independent predictor of outcome.
Conclusions: Both abdominal and psychological symptoms are independently associated with impaired health-related quality of life in patients with severe IBS. Optimal treatment is likely to require a holistic approach. Since health care and loss of productivity costs are not clearly associated with these symptoms, alleviation of them will not necessarily lead to reduced costs.