By Deborah Brauser
ORLANDO, Fla -- October 9, 2008 -- Antidepressants are an effective treatment for patients with irritable bowel syndrome (IBS), according to results presented here at the American College of Gastroenterology (ACG) 73rd Annual Scientific Meeting.
Alexander Ford, MD, McMaster University Medical Centre, Hamilton, Ontario, reported the results of a systematic review in a poster session here on October 5.
"I think the most exciting finding [of our study] is that this hasn't been shown before. It's probably the first time that a systematic review and meta-analysis has shown that antidepressants are a benefit in treating irritable bowel syndrome," said Dr. Ford.
"Previous meta-analyses have not demonstrated such an effect for a number of reasons. Obviously, there's more data now but also [researchers] haven't quite looked at all of the eligible studies for various reasons. I think one of [the studies] should have been able to demonstrate this benefit 3 or 4 years ago, but just didn't manage to."
For this study, Dr. Ford and his fellow investigators searched MEDLINE, EMBASE, and the Cochrane Controlled Trials Register for randomised controlled trials up to April 2008 that compared antidepressants with placebo in adults with IBS. They found 13 trials eligible for inclusion, with a total of 789 patients. Eight of the trials used tricyclic antidepressants (TCAs), 4 used selective serotonin reuptake inhibitors (SSRIs), and 1 used both drug classes.
Data were extracted as intention-to-treat analyses and pooled using a random effects model. The effect of antidepressants on IBS symptoms compared with placebo was reported as the relative risk of remaining symptomatic, with a 95% confidence interval (CI). The number needed to treat and the 95% CIs were calculated from the reciprocal of the risk difference from the meta-analysis.
Results of the review showed that 42.1% of the 432 patients treated with antidepressants had persistent or unimproved IBS symptoms compared with 64.7% of 357 given placebo. The relative risk of IBS symptoms persisting after treatment with antidepressants versus placebo was 0.66 (95% CI, 0.57 to 0.78). The number needed to treat with antidepressants was 4 (95% CI, 3 to 6).
In the 9 trials that compared TCAs and placebo, 41.4% of the 319 subjects receiving TCAs had persistent symptoms after treatment compared with 59.8% of 256 receiving placebo. The relative risk of IBS symptoms persisting was 0.68 (95% CI, 0.56 to 0.83). The number needed to treat with TCAs was 4 (95% CI, 3 to 8).
In the 5 trials that compared SSRIs and placebo, 44.2% of the 113 patients in the SSRIs group had persistent symptoms following therapy compared with 70.9% of 117 placebo patients. The relative risk of IBS symptoms persisting with SSRIs compared with placebo was 0.62 (95% CI, 0.45 to 0.87), and the number needed to treat was 3.5 (95% CI, 2 to 14).
"I think there should be a willingness to use antidepressants more readily now," Dr. Ford said. "When a patient fails first-line therapies, that should be the point in which you consider discussing whether or not they want to try either a tricyclic or an SSRI."
"Biologically, you would think it would be better to use tricyclics in diarrhoea-predominant patients and it would be better to use SSRIs in constipated predominant ones. Unfortunately, the studies that have been published that we have identified don't actually break down their patients according to the predominant symptoms and subgroups. But it's biologically plausible that that would be the best way to use it."
Dr. Ford concluded that doctors should be sensitive when first broaching the subject of antidepressants with patients, due to the stigma that is often attached. "There's obviously that reluctance on [the patient's] part that you're trying to label them as being mad or depressed," said Dr. Ford. "I think you have to make it clear to them that these are benefits for symptoms of IBS and that that's what's being treated -- not any coexisting depression. And that all of that is kept completely separate."
[Presentation title: Efficacy of Antidepressants in Irritable Bowel Syndrome: Systematic Review and Meta-Analysis. Abstract P312]
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