OBJECTIVES: The goal of this study was to evaluate the association between adherence to biologic medications, medical costs, hospitalizations, and bed days in patients with ulcerative colitis (UC) or Crohn’s disease.

METHODS: Pharmacy and medical claims from the 2019 MarketScan Commercial Claims and Encounters database were used for this study. A PQA-like proportion of days covered (PDC) metric was created to assess adherence to biologic medications among patients who had >2 medical claims (>30 days apart) with ICD-10 codes for UC or Crohn’s disease during the year. Adult patients (>18 years) were eligible for PDC calculation if they had >2 pharmacy claims, >56 days-supply, and an index date that did not fall within the last 90 days of the period. Patients were excluded if they did not have >150 days between the first and last fill for any medication, as a proxy for continuous enrollment in a health plan. Being adherent was defined as >80% PDC. Outcomes examined included hospitalizations, inpatient bed days, and inpatient costs. The methods of this study were reviewed and approved by Advarra IRB.

RESULTS: In total, 8,849 and 3,106 patients had sufficient data to calculate PDC and met diagnostic criteria for Crohn’s and UC, respectively. The most commonly used medication in both groups was adalimumab (UC=85.8%,Crohn’s=66.7%). Roughly 2 out of 3 patients were adherent to their medications (UC=66.1%,Crohn’s=64.6%). Fewer adherent patients were hospitalized during the year (UC=9.6%,Crohn’s=13.4%) than non-adherent patients (UC=18.1%,Crohn’s=21.6%;ps<.001). Among patients who had a hospitalization, adherent patients had fewer inpatient bed days (UC=5.6,Crohn’s=5.9) than non-adherent patients (UC=8.7,Crohn’s=8.7;ps<.001). Similarly, adherent patients had lower inpatient costs (UC=$23,390,Crohn’s=$33,909) than non-adherent patients (UC=$47,700,Crohn’s=$49,278;ps<.001).

CONCLUSION: The results of this study suggest that adherence to biologic therapies may result in lower hospitalization rates and inpatient costs. Specialty pharmacy interventions focused on adherence to biologics could help reduce medical burden.