IBS Hints at Migraine, Fibromyalgia, and Depression

BOSTON, Sept. 28 -- When a diagnosis of irritable bowel syndrome (IBS) comes to mind, consider migraine, fibromyalgia, and depression as well.

Patients with IBS were 60% more likely to have one of those conditions than were those who didn't have IBS, according to J. Alexander Cole, D.Sc., M.P.H., of Boston University, and colleagues, who studied nearly 100,000 IBS patients enrolled in a national health insurance plan.

Patients who were treated for IBS were 40% more likely to have depression, 60% more likely to suffer migraine, and 80% more likely to seek treatment for fibromyalgia, they reported in the current issue of BMC Gastroenterology.

Dr. Cole and colleagues used a database of medical and pharmacy claims filed from January 1, 1996, through June 30, 2002, to identify 97,593 people who were treated for IBS.

They compared the IBS cohort with a random sample of 27,402 who were enrolled in the same health insurance plan.

Women comprised about 75% of the IBS cohort and roughly half of the controls. Age ranged from 18 to more than 65 and distribution was similar in both groups.

In the IBS cohort the prevalence of having at least one of the three disorders (migraine, depression, or fibromyalgia) was 264 per 1,000, they wrote. By contrast, the prevalence in the control group was 46 per 1,000.

In both control and IBS cohorts depression was the most prevalent condition, with a prevalence of 128 per 1,000 among IBS patients and 60 per 1,000 in the controls.

Those in the IBS cohort had a pooled prevalence odds ratio of 1.6 for having one of the three conditions (95% confidence interval 1.5-1.7), while the pooled odds ratio for fibromyalgia in the IBS was 1.8 (95% CI, 1.7-1.9). For migraine the IBS patients had a pooled odds ratio of 1.6 (95% CI, 1.4-1.7) and for depression it was 1.4 (95% CI 1.3-1.4).

The authors cautioned that relying on medical and pharmacy claims data limited the ability to ascertain clinical characteristics, such as the predominant symptom of IBS -- constipation or diarrhea -- that might confound the relationship they reported. The lack of that information also prevented them from determining whether there was heterogeneity in the prevalence of depression, fibromyalgia, and migraine in the IBS cohort.