Certain patients with irritable bowel syndrome (IBS) may benefit from treatment with mesalamine, although the quality of evidence supporting this strategy remains low, according to a recent systematic literature review and meta-analysis.
Global IBS symptoms improved significantly across the entire population, however, a subgroup analysis suggested that mesalamine may be most beneficial for patients who present with diarrhea, providing support for a large clinical trial in this patient population, reported lead author Vivek C. Goodoory, MBChB, of St. James’s University Hospital, Leeds, United Kingdom, and colleagues.
Dr. Vivek C. Goodoory
Some patients with IBS may present with low-grade inflammation in the intestine, offering theoretical grounds for prescribing mesalamine, which is typically used for treating ulcerative colitis, the investigators wrote in Clinical Gastroenterology and Hepatology. Yet previous randomized controlled trials (RCTs) evaluating mesalamine for IBS have yielded mixed results, and a meta-analysis showed that mesalamine offered no benefit.
According to Dr. Goodoory and colleagues, however, that meta-analysis fell short since it “only pooled mean symptom scores, rather than the proportion of patients in each trial experiencing an improvement in symptoms, and did not appear to include data from all available RCTs.” Furthermore, they noted that this prior study lacked subgroup analyses conducted based on IBS subtype or postinfection status.
“We, therefore, conducted a contemporaneous meta-analysis to examine the efficacy and safety of mesalamine in IBS addressing these deficits in knowledge,” the investigators wrote.
Their meta-analysis included 820 patients from 8 RCTs published between 2009 and 2022. Efficacy and safety were evaluated via dichotomous assessments of global IBS symptoms, bowel habit or stool frequency, abdominal pain, and adverse events. Two subgroup analyses were planned to evaluate responses based on post-infection status and predominant stool pattern.
Unlike the previous meta-analysis, Dr. Goodoory and colleagues detected a potential signal for efficacy.
Across all patients, mesalamine was associated with significant improvement in global IBS symptoms, compared with placebo (relative risk [RR], 0.86; 95% CI, 0.79-0.95). However, no significant improvements were detected for abdominal pain or bowel habit/stool frequency.
A subgroup analysis of patients exhibiting IBS with diarrhea showed significantly greater improvements in global IBS symptoms for mesalamine versus placebo (RR, 0.88; 95% CI, 0.79-0.99). This subgroup showed no improvements in abdominal pain or bowel habit/stool frequency.
Subgroup analyses for patients with constipation or mixed bowel habits, or based on postinfection status, revealed no significant differences, although the investigators noted that relevant data were limited.
Mesalamine appeared to be well tolerated. Across five studies reporting adverse events, 43.5% of patients receiving mesalamine reported any adverse event, compared with 41.4% of patients on placebo. The RR of experiencing an adverse event in those taking mesalamine was 1.20 (95% CI, 0.89-1.63), which was not statistically significant.
“There was no evidence of heterogeneity between studies in most of our analyses, but only one trial was at low risk of bias across all domains, and there were insufficient studies to assess for funnel plot asymmetry,” Dr. Goodoory and colleagues wrote. “Based on these limitations of the evidence,” they continued, “our confidence in the results of the meta-analysis would be low, and further large trials at low risk of bias would be informative.”
Specifically, the investigators suggested an RCT recruiting only patients with IBS with diarrhea, and reporting efficacy according to postinfection status.
One coauthor reported research funding from Tillotts Pharma and Dr Falk Pharma UK. The remaining authors reported no conflicts.