Declining Rates of Referral for Irritable Bowel Syndrome Without Constipation at a Tertiary Care Center.

BACKGROUND: Irritable bowel syndrome (IBS) is a common chronic disorder of the gastrointestinal tract. Several treatments have been developed, including rifaximin for the treatment of IBS without constipation (non-IBS-C), but no studies have evaluated the effect of these therapies on patient referral rates to tertiary care gastroenterology clinics. AIM: To assess referral patterns for IBS patients at a tertiary motility clinic over a 10-year period. METHODS: Data from consecutive patients referred to the clinic during 2006-2016 were analyzed. Trends in the proportion of referrals and prior rifaximin use in IBS-C versus non-IBS-C groups were compared. RESULTS: A total of 814 adult patients were referred to a single physician panel for IBS-related symptoms. Of these, 776 were included in the study [528 females (68%), average age 45.7 ± 15.9 years), comprising 431 IBS-C (55.5%) and 345 non-IBS-C (44.5%) patients. The proportion of non-IBS-C referrals declined significantly from 53.0% in 2006 to 27.3% in 2016 (Chi-square, p < 0.0001, Cochran-Armitage trend test p = 0.0001), and the proportion of IBS-C referrals increased significantly from 46.9% in 2006 to 72.7% in 2016 (Chi-square, p < 0.0001, Cochran-Armitage trend test p = 0.0004). Non-IBS-C referrals with prior rifaximin use significantly increased from 22.7% in 2006 to 66.7% in 2016 (Cochran-Armitage trend test, p = 0.008). CONCLUSIONS: The results indicate a significantly declining tertiary care referral rate for non-IBS-C over the past decade. While not directly linked, there has been an increase in rifaximin use in the same population during the same time interval.

Antibiotic treatment of constipation-predominant irritable bowel syndrome.

BACKGROUND: The antibiotic rifaximin is used to treat non-constipated irritable bowel syndrome (IBS). Methane production is associated with constipation and its severity in constipation-predominant IBS (C-IBS). A previous retrospective study suggested that rifaximin and neomycin was superior to neomycin alone in improving symptoms in methane-positive subjects. AIMS: To determine the effectiveness of neomycin alone or with rifaximin in improving symptoms in methane-positive C-IBS subjects. METHODS: A double-blind, randomized, placebo-controlled trial was performed from 2010 to 2013 at three tertiary care centers. Subjects aged 18-65 with C-IBS (Rome II criteria) and breath methane (>3 ppm) meeting the inclusion and exclusion criteria were recruited. Subjects completed a baseline symptom questionnaire rating the severity of abdominal and bowel symptoms on a visual analog scale and were randomized to receive neomycin and placebo or neomycin and rifaximin for 14 days. Symptom severity was assessed by weekly questionnaire for 2 weeks of therapy and 4 additional weeks of follow-up. RESULTS: Thirty-one subjects (16 neomycin and placebo, 15 neomycin and rifaximin) were included in the intention-to-treat analysis. Constipation severity was significantly lower in the neomycin and rifaximin group (28.6 ± 30.8) compared to neomycin alone (61.2 ± 24.1) (P = 0.0042), with greater improvement in constipation (P = 0.007), straining (P = 0.017) and bloating (P = 0.020), but not abdominal pain. In the neomycin and rifaximin group, subjects with methane <3 ppm after treatment reported significantly lower constipation severity (30.5 ± 21.8) than subjects with persistent methane (67.2 ± 32.1) (P = 0.020). CONCLUSIONS: Rifaximin plus neomycin is superior to neomycin alone in improving multiple C-IBS symptoms. This effect is predicted by a reduction in breath methane.