Medication adherence among patients with gout: A systematic review and meta-analysis

Objective: In the management of chronic gout, a large proportion of patients need long-term management with urate lowering therapy (ULT). This study reviews medication adherence to ULT and summarizes factors associated with adherence. Methods: We performed a systematic literature search for studies on adherence to ULT among gout patients in PubMed, Embase, CINAHL, and PsycINFO. We conducted meta-analysis, with a random effect model, for the studies reporting the proportion of patients considered adherent to at least 80% of prescribed medication or time taken. We explored potential sources of heterogeneity, including geographic area and measure of adherence. Narrative summaries were made for data on adherence assessed/defined by Medication Event Monitoring System (MEMS)/pill-count or patient-reported, occurrence of a gap in therapy >= 30 days (non-persistence), and factors associated with adherence. Results: Of the 24 studies, 16 assessed adherence using prescription/claims data, two by the MEMS or pill count, and six by patient-reported data. The pooled proportion of adherent patients (n = 13) was 46% (95% CI: 41-51); 45% across studies conducted in the USA (n = 8) and 48% in other countries (n = 5). Adherence assessed by MEMS/pill count and patient-reported was much higher than by studies using prescription/claims data. Non-persistence (n = 6) ranged from 54% to 87%. Factors associated with adherence were investigated in 18 studies. Strong evidence for a positive association with older age, more comorbidities, and the presence of diabetes or hypertension was found. Conclusion: Medication adherence to ULT among gout patients was poor. Better insight into reasons and consequences or poor adherence is needed. (C) 2018 Elsevier Inc. All rights reserved.