Background: It is unclear why patients with irritable bowel syndrome (IBS) consume a disproportionate amount of health-care resources versus matched controls. One possibility is the presence of comorbid somatization-a process marked by multiple unexplained somatic complaints that is highly prevalent in IBS. We sought to determine whether higher levels of somatization are associated with higher levels of gastrointestinal (GI) resource utilization in IBS.
Methods: A total of 1,410 patients >18 yr with IBS were evaluated at a university-based clinic. Subjects completed a symptom questionnaire, the SCL-90R psychometric checklist, and the SF-36 Health Survey. We measured two outcomes: (1) a 1-yr direct GI health-care costs and (2) a 1-yr number of GI physician visits. Our primary regressor was somatization as measured by the somatization subscale of the SCL-90R. We performed regression analyses to measure the adjusted influence of somatization on GI resource utilization.
Results: In the full sample of patients, there were no differences in the likelihood of expending versus not expending previous GI health-care costs among groups with varying levels of somatization. Similarly, there were no differences in either the likelihood of visiting a GI physician or the number of overall physician visits among patients with varying levels of somatization. However, in the subset of patients expending at least $1.00 in GI costs in the previous year (53% of cohort), there was a significantly higher cost of care for subjects with high versus low levels of somatization.
Conclusions: IBS patients with high levels of somatization are not more likely to seek GI care compared to patients with low levels of somatization. However, once they are evaluated for care, patients with high somatization expend significantly more GI health-care costs. This suggests that somatization is positively associated with health-care costs in IBS, and that the association may be driven more by physicians than patients.