Self-Reported Use of Pharmaceuticals Among Patients With Irritable Bowel Syndrome in Primary Care

BACKGROUND: Irritable bowel syndrome (IBS) has an estimated 10%-12% prevalence in industrial countries. Studies from the United States have shown that IBS causes notable financial losses for employers. Due to the lack of pathophysiological markers, only a fraction of the pharmacological management of IBS has focused on etiological mechanisms. We hypothesized that there is a high consumption of nonspecific drugs among patients with IBS in their attempts to manage symptoms. OBJECTIVES: To analyze self-reported use of prescription and over-the-counter (OTC) drugs among patients with IBS in primary care compared with controls from the general population. METHODS: A population-based case-control design was used for the study. IBS cases were identified from the electronic medical records of 3 Swedish primary health care centers from January 1, 1997, through December 31, 2001. A questionnaire containing specific questions about prescription and OTC drugs was mailed in 2003 to 5,015 working-age (18-64 years) individuals (IBS cases and controls) in the Linkoping IBS Population Study, a study of primary care patients with controls selected from the general population. RESULTS: After 2 reminders, the overall response rate was 63% (3,074 respondents of 4,913 deliverable surveys); 71% responded for the IBS cases (347/486) and 57% (2,509/4,427) responded for the controls. 72.3% of the IBS respondents and 51.9% of the controls were female. Acid-suppressive agents were the most commonly cited drug category for abdominal complaints reported by IBS patients (13.3%) compared with controls (1.6%) (unadjusted odds ratio [OR] = 9.20, 95% confidence interval [CI] = 5.94-14.25). Antidepressants were the most commonly cited drug category for nonabdominal complaints, reported by 13.3% of IBS patients versus 4.5% of controls (OR = 3.27, 95% CI = 2.27-4.70). An unadjusted univariate correlation analysis revealed that prescription acid-suppressive drugs, fiber and bulking laxatives, and antiflatulents and antidiarrhea drugs, as well as motility-regulating and antispasmodics drugs, were significantly more common among IBS cases compared with controls. In addition to the higher use of antidepressants, there were 3 other drug classes for nongastrointestinal complaints with a higher rate of use among IBS patients compared with controls: sedative hypnotics (OR = 2.49, CI = 1.44-4.29), analgesics (OR = 2.86, CI = 1.88-4.33), and thyroid hormones (OR = 2.43, CI = 1.39-4.26). CONCLUSIONS: There was higher use of antidepressants among patients with IBS compared with controls from the general population. Even though they are not recommended for this patient category, the use of prescription and OTC acid-suppressive drugs is also common among IBS cases in primary care.