A comprehensive review was performed to investigate the effect of route of administration on medication adherence and persistence in rheumatoid arthritis (RA) and to compare adherence/persistence with oral medications between RA and a non-painful disease (dyslipidemia).
Comprehensive database searches were performed to identify studies investigating medication adherence and/or persistence in adults with RA receiving conventional synthetic or biologic agents. Similar searches were performed for studies of patients with dyslipidemia receiving statins. Studies had to be published after 1998 in English and involve ≥6 months' follow up.
Adherence and persistence were compared between the different routes of drug administration in RA, and between the two diseases for oral medications.
A total of 35 and 28 papers underwent data extraction for RA and dyslipidemia, respectively. Within the constraints of the analysis, adherence and persistence rates appeared broadly similar for the different routes of drug administration in RA. Adherence to oral medications was also broadly similar across the two diseases, but persistence was lower in dyslipidemia. Poor adherence has clinical consequences in both diseases: greater disease activity and risk of flare in RA, and increased serum cholesterol levels and risk of heart and cerebrovascular disease in dyslipidemia. Over 1-3 years, poor adherence to biologic RA medications led to increased resource use and medical costs but lower total direct costs due to reduced biologic drug costs. Conversely, poor adherence to dyslipidemia medications resulted in increased total direct costs. In both diseases, adherence improved with patient education/support.
The wide range of adherence and persistence values and definitions across studies made comparisons between drug formulations and diseases difficult.
The route of drug administration and the symptomatic (pain) nature of the disease do not appear to be dominant factors for drug adherence or persistence in RA.