Factors associated with adherence to ursodeoxycholic acid or placebo in patients after bariatric surgery

Ursodeoxycholic acid (UDCA) reduces symptomatic gallstone disease after Roux-en-Y gastric bypass (RYGB). The beneficial effect of UDCA is reduced by poor adherence.

We aimed to identify factors associated with poor adherence to UDCA or placebo after bariatric surgery.

Outpatient clinic and department for bariatric surgery in three hospitals in the Netherlands.

Patients in the multicenter, double-blind, randomized, placebo-controlled UPGRADE trial were assessed for adherence to 900 mg UDCA or placebo for 6 months through a pill count, inquiries during follow-up, and a questionnaire. Poor adherence was defined as the usage of <300 of 364 pills within a maximum of 8 months postoperatively. Multivariable logistic regression analysis was used to identify factors contributing to poor adherence.

In total, 967 patients were included (mean age [standard deviation (SD)]: 45.1 [11.1] years; female: 772 [80%]; RYGB: 889 [92%]; sleeve gastrectomy: 78 [8%]), of whom 357 (37%) were poor adherers. Factors associated with poor adherence were age (OR .97; 95% confidence interval [CI] .96-.98, a decrease in age increases the odds for poor adherence), foreign origin (odds ratio [OR] 2.07; 95%CI 1.50-2.84), unemployment (OR 1.73; 95%CI 1.28-2.34), and sleeve gastrectomy (OR 1.79; 95%CI 1.06-3.01). Furthermore, a difference in adherence status was also noted for the centers of surgery.

The adherence rate to UDCA and placebo in the UPGRADE trial was suboptimal. Several factors were independently associated with poor adherence. Our findings can help to identify patients who may benefit from extra guidance to improve adherence.