Adherence and persistence in patients with rheumatoid arthritis at an integrated health system specialty pharmacy

BACKGROUND: Disease-modifying anti-rheumatic drugs (DMARDs) improve symptoms and delay progression of rheumatoid arthritis (RA), but adherence is often sub-optimal and many patients change medication (either “switching” to a medication with a different mechanism of action or “cycling” to a medication with the same mechanism of action) during the first year of therapy. Some integrated health-system specialty pharmacies embed pharmacists in clinics to help patients access and adhere to specialty medication. OBJECTIVE: This study assessed DMARD switching, cycling, adherence, and persistence at an outpatient rheumatology clinic with an integrated health-system specialty pharmacy. METHODS: We conducted a retrospective cohort study of adults with RA, naïve to biologic or targeted synthetic DMARDs, who filled ≥ 2 biologic or targeted synthetic DMARD prescriptions within 12 months. Adherence was measured using proportion of days covered (PDC); persistence was computed at 12 months. Univariate analyses compared adherence and persistence between patients with and without a medication change. Ordinal logistic regression examined whether PDC was associated with patient age, gender, race, insurance type, and medication change. RESULTS: We included 772 patients: 79% female/21% male, 89% White/11% non-White, median age 56 years (interquartile range = 48-63). Most patients (84%) did not change medication during the study period, 5% cycled medication one or more times (but did not switch), 9% switched medication one or more times (but did not cycle), and 2% of patients both switched and cycled during the study period. Median PDC of the sample was 0.94 and 73% of patients were persistent. Patients with a medication change had lower PDC than those without (0.89 vs 0.95, P = 0.004), but rate of persistence did not significantly differ between groups (77 vs 72%, P = 0.300). Odds of higher PDC was more likely for men (Odds ratio [OR] = 1.82, 95% confidence interval [CI]: 1.34-2.48, P < 0.001) and less likely for patients who changed medication (OR = 0.65, CI: 0.47-0.91, P = 0.011); age, race, and insurance type were not significant. CONCLUSIONS: Patients with RA demonstrated high medication adherence and persistence, and low rates of switching and cycling. Findings support evidence that integrated health-system specialty pharmacies with clinical pharmacists embedded in outpatient clinics help patients overcome barriers to medication adherence to persist on therapy.