The relationship between somatisation and outcome in patients with severe irritable bowel syndrome

Abstract

Objective This study aimed to assess the relationship between somatisation and outcome in patients with severe irritable bowel syndrome (IBS). Method Two hundred fifty-seven patients with severe IBS included in a randomised controlled trial were assessed at baseline and divided into four quartiles on the basis of their somatisation score. The patients were randomised to receive the following over 3 months: brief interpersonal psychotherapy, 20 mg daily of the SSRI antidepressant paroxetine, or treatment as usual. Outcome 1 year after treatment was assessed using the Short Form-36 physical component summary (PCS) score and total costs for posttreatment year. Results The patients in the quartile with the highest baseline somatisation score had the most severe IBS, the most concurrent psychiatric disorders, and the highest total costs for the year prior to baseline. At 1 year after the end of treatment, however, the patients with marked somatisation, who received psychotherapy or antidepressant, had improved health status compared to those who received usual care: mean (S.E.) PCS scores at 15 months were 36.6 (2.2), 35.5 (1.9), and 26.4 (2.7) for psychotherapy, antidepressant, and treatment-as-usual groups, respectively (adjusted P=.014). Corresponding data for total costs over the year following the trial, adjusted for baseline costs, were £1092 (487), £1394 (443), and £2949 (593) (adjusted P=.050). Conclusions Patients with severe IBS who have marked somatisation improve with treatment like other IBS patients and show a greater reduction of costs. Antidepressants and psychotherapy are cost-effective treatments in severe IBS accompanied by marked somatisation.