Studies demonstrate conflicting findings on impact of obesity on treatment response, outcomes in IBD
Obesity does not appear to have a significant influence on treatment response and clinical outcomes in patients with inflammatory bowel disease (IBD), according to two studies presented at the 2018 Crohn’s & Colitis Congress (CCC).
A pooled analysis of the infliximab arms of six trials (n=1,399, mean age 36 years, 52 percent males, 14 percent obese) revealed no association between obesity and the odds of achieving clinical remission (adjusted odds ratio [adjOR], 0.94, 95 percent confidence interval [CI], 0.61–1.47; ptrend=0.97), clinical response (adjOR, 0.84, 95 percent CI, 0.52–1.35; p=0.45), or mucosal healing remission (adjOR, 1.13, 95 percent CI, 0.55–2.34; p=0.95). [2018 CCC, abstract 186]
Furthermore, pooled evaluation of the placebo arms of four trials (n=575, mean age 38 years, 52 percent males, 16 percent obese) revealed similar results, demonstrating a lack of association between obesity and the odds of achieving clinical remission (adjOR, 1.36, 95 percent CI, 0.65–2.89; ptrend=0.57), clinical response (adjOR, 1.31, 95 percent CI, 0.61–2.81; p=0.45), or mucosal healing remission (adjOR, 0.55, 95 percent CI, 0.12–2.34; p=0.31). [2018 CCC, abstract 183]
The findings of these two pooled analyses suggest that obesity does not influence response to the biologic agent infliximab nor does it affect short- and intermediate-term clinical outcomes in patients with IBD, said the researchers.
Higher BMI = increased treatment failure
A retrospective study comprising 160 biologic-treated patients (55 percent infliximab) with ulcerative colitis (median age 36 years, 50 percent males) showed conflicting results, demonstrating an association between a higher body mass index (BMI) and an increased risk of treatment failure and surgery. [2018 CCC, abstract 24]
Multivariate analysis revealed that every 1 kg/m2 increase in BMI was associated with an increased risk of treatment failure (adjusted hazard ratio [adjHR], 1.04, 95 percent CI, 1.00–1.08; p=0.034) and surgery or hospitalization (adjHR, 1.08, 95 percent CI, 1.02–1.14; p=0.008), as well as a reduction in achieving endoscopic remission (adjOR, 0.94, 95 percent CI, 0.87–1.00; p=0.070).
The effect on treatment failure was observed among participants receiving fixed-dose (adjHR, 1.05, 95 percent CI, 0.99–1.12; p=0.106) or weight-based dosing regimens (adjHR, 1.05, 95 percent CI, 1.00–1.10; p=0.05).
“[Our findings show that] BMI is independently associated with decreased response to biologic agents in patients [with ulcerative colitis], which may be independent of dosing regimen,” said the researchers of this study.
Given these conflicting findings, further investigation is warranted to elucidate the influence of obesity on treatment response and long-term outcomes in IBD, said the researchers of the two pooled analyses.