In IBD, Can Identifying Risk Factors Improve Drug Adherence? 

PHILADELPHIA—Identifying risk factors for nonadherence of biologic medications can lead to improved adherence among patients with inflammatory bowel disease (IBD), according to study findings presented today at the American College of Gastroenterology’s Annual Meeting.

“We can allocate valuable and limited health care resources only to those at greatest risk rather than the entire population,” Dr Sara Horst, associate professor at Vanderbilt University Medical Center, told Gastroenterology Consultant.

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Nonadherence to biologic therapeutics could pose various risks for patients, such as increased risk of anti-drug antibody formation and consecutive medication failure.

“There is a need to better understand how to help and make sure patients take the medications that are prescribed,” Horst said.

For this study, Horst and colleagues evaluated 460 patients treated with injectable biologic therapy—adalimumab, certolizumab, golimumab, or ustekinumab—at Vanderbilt’s IBD center. Patients were also followed by the center’s specialty pharmacy, which was defined as a minimum of 3 prescription claims.

Medication possession ratio (MPR) was estimated as the sum of days’ supply for all prescription claims divided by the total number of days transpired in the study period. Medication nonadherence was defined as an MPR less than 0.86. 

A total of 69% of patients were adherent to medication. Among these, 71% had Crohn disease, and 87% had ulcerative colitis. The overall mean MPR was 0.89.

Horst attributed a high adherence rate to the center’s multidisciplinary team-based approach: “It is possible that this could have helped with medication adherence in general. However, even within this group, we found several risk factors that increased the risk of nonadherence.”

Univariate analysis identified Crohn disease diagnosis, insurance type, psychiatric history, smoking, prior biologic use, and narcotic use as risk factors for nonadherence. However, disease type and past surgical history in Crohn disease were not.

The number of risk factors increased the likelihood of nonadherence among patients with Crohn disease. Adherence was 77% for patients with 0 risk factors, 73% for patients with 1 risk factor, 65% for patients with 2 risk factors, 61% for those with 3 risk factors, and 37% for those with 4 risk factors.

Results of the multivariate analysis showed that Medicaid insurance and diagnosis of Crohn disease increased patients’ risk for noncompliance, but several risk factors trended toward significance.

“We plan to further understand the driving forces behind nonadherence in the patient populations most at risk for nonadherence,” Horst said. “We are also working on a prospective study to evaluate interventions that may improve adherence, especially in those at greatest risk for future nonadherence.”

—Melinda Stevens

Reference:
Haydek J, Shah NB, Slaughter J, et al. Risk factors for medication non-adherence to biologic therapy in patients with inflammatory bowel disease: a retrospective analysis. Paper presented at: American College of Gastroenterology Annual Meeting 2018; Philadelphia, PA. https://www.eventscribe.com/2018/ACG/agenda.asp?h=Full%20Schedule&BCFO=P|G.  Accessed October 5, 2018.