Medication adherence and persistence in patients with rheumatoid arthritis, psoriasis, and psoriatic arthritis: a systematic literature review

Purpose: Proper adherence and persistence to medications are crucial for better quality of life and improved outcomes in rheumatoid arthritis (RA), psoriasis (PsO), and psoriatic arthritis (PsA). We systematically describe current adherence and persistence patterns for RA, PsO, and PsA, with a focus on biologics and identifying factors associated with adherence and persistence. Patients and methods: Using various databases, a systematic literature review of US-based studies published from 2000 to 2015 on medication adherence and persistence to biologics and associated factors was conducted among patients with RA, PsO, and PsA. Results: Using the medication possession ratio or the percentage of days covered >80%, RA and PsO adherence rates for etanercept, adalimumab, and infliximab ranged from 16% to 73%, 21% to 70%, and 38% to 81%, respectively. Using the criteria of a >= 45-day gap, RA persistence rates for etanercept, adalimumab, and infliximab ranged from 46% to 89%, 42% to 94%, and 41% to 76%, respectively. In PsO, persistence rates for etanercept and adalimumab ranged from 34% to 50% and 50% to 62%, respectively. Similar persistence rates were observed in PsA. Experienced biologics users showed better adherence and persistence. Younger age, female gender, higher out-of-pocket costs, greater disease severity, and more comorbidities were associated with lower adherence and persistence rates. Qualitative surveys revealed that nonpersistence was partly due to perceived ineffectiveness and safety/tolerability concerns. Conclusion: Biologic adherence and persistence rates in RA, PsO, and PsA in the United States were low, with significant opportunity for improvement. Various factors - including decrease in disease severity; reduction of comorbidities; lower out-of-pocket costs; refilling at specialty pharmacies; and awareness of drug effectiveness, safety, and tolerability - can inform targeted approaches to improve these rates.