Comorbidity and psychological distress in irritable bowel syndrome (IBS)

Abstract

We previously' (Gastro 2002,122(Suppl 1):A502) developed and validated the IBS-specific Recent Physical Symptoms Questionnaire (RPSQ) and Comorbid Medical Conditions Questionnaire (CMCQ) based on a systematic literature review We hypothesized that the excess comorhid medical cooditions and non-gastrointestinal symptoms seen in 1BS constitute somatization, that is, expresskm of psychological distress thmugb physieal symptoms (Gastro 2002;122(4):1140-56). Aims: (1) Test the hy'pothesis that comorbidity m IBS is related to anxiety and depression and (2) quantity ' the impact of excess comorbidity on IBS symptom severity, disability, quality of fite and IBScelated health care utilization. Methods: The RPSQ and CMCQ were mchided in a marl survey completed by 1603 patients with functional bowel diagnoses in a large nortfiwestem US. health maintenance organization within 2 weeks of a clinic visit. The survey also included the IBS-QOL (Dig Dis Sci 1998;43:40011), the IBS Seventy Index (Aliment Pharmacol Tber 1997;11:395-402) the Brief Symptom Inventory' -18 (NCS Pearson, Inc.) attd questions about doctor's visits and disability days. Data from the 7g\5 IBS patients who met Rome II criteria were analyzed. Results: RPSQ # of non-gastrointestinal (non-GI) symptoms and CMCQ # of comorbid medical diagnoses were moderately intercorrelated (r= 49, p 1 standard deviation above the sample mean) on either comorbidity scale bad greater quality of li|e impairment, more than 3 times the number of disability days m the past year, and greater overall IBS symptom severity (p<.001 m all comparisons). High number of co-morbid medical diagnoses, but not nonspecific symptoms contributed to more frequent (p<.01) doctors' visits due to bowel symptoms in the past 6 montha Conclusions: Our results support the hypothesis that comorbidity in IBS is an expression of psychological distress. High number of co-morbid diagnoses and non*GI symptoms are related to a substantiaUy greater IBS morbidity, disability and worse quality ot lite. (Supported by RO1 DK31369, ROI HD36069 and a grant fi'om Novartis Pharmaceuticals Corp.)