Biologic agents raise IBD risk among axSpA patients

Based on observational studies, patients with axial spondyloarthritis (axSpA) treated with biologics are at higher risk of inflammatory bowel disease (IBD), while findings from randomized controlled trials (RCTs) suggest that treatment with etanercept (ETN) tends to increase such risk compared to other antitumour necrosis factor (anti-TNF) therapies, according to the result of a meta-analysis.

A team of investigators used data from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS) to determine the incidence of IBD during follow-up and calculate the incidence rate difference (IRD) per 1,000 person-years between biologic treatment and other treatment groups. They then performed a systematic review and meta-analysis of observational studies and RCTs to measure the difference in incidence of IBD between treatment groups.

Based on data from BSRBR-AS, patients with axSpA with exposure to biologic therapy exhibited an increased IBD incidence relative to those without exposure (IRD, 11.9, 95 percent confidence interval [CI], 4.3‒19.6). This finding was consistent across observational studies but was not observed in placebo-controlled RCTs (IRD, 2.2, 95 percent CI, ‒4.1 to 8.5).

In addition, BSRBR-AS data showed no association between a higher IBD incidence and exposure to ETN compared to other anti-TNF therapies (IRD, ‒6.5, 95 percent CI, ‒21.3 to 8.5). However, findings from RCTs and their extensions indicated a small, but not statistically significant, absolute increased IBD incidence with ETN exposure (between 2.1 and 5.8 per 1,000 person-years) vs other anti-TNF therapies.