Background/Purpose: Recent data suggesting the growing problem of medication non-adherence in gout has called for the need to understand the magnitude of the problem as well as its determinants. To date, only one systematic review has summarized medication adherence across a variety rheumatic diseases, including three studies in gout. To update this data as well as better understand patterns and determinants of adherence in this population, our objective was to a conduct a systematic review of the literature examining medication adherence among patients with gout.

Methods: We conducted a systematic search of MEDLINE (1946-), EMBASE (1974-), and INTERNATIONAL PHARMACEUTICAL ABSTRACTS (1970-) databases and selected original studies that included patients with gout and measured and/or reported medication adherence in real-world settings. We extracted information on: 1) study design, 2) sample size, 3) length of follow-up, 4) data source (e.g. prescription records vs. electronic monitoring vs. self-report), and 5) adherence measures and reported estimates. We assessed quality of studies by adapting and applying published recommendations for the reporting, assessment, and evaluation of medication adherence studies.

Results: After screening 963 potential articles, 14 met inclusion criteria. We divided studies according to methods used to measure adherence including prescription records (9), electronic monitoring devices (1), and self-report (4). Studies using prescription records have the largest sample sizes and lowest reported adherence, ranging from 17% to 44%.  Higher adherence rates (or scores) were reported in studies based on self-report, which may be due to social desirability bias. With respect to determinants, younger age has been shown as a predictor of poor adherence while other factors including gender and gout-related factors (e.g., flares) are less consistent across studies.

Conclusion: This is the first systematic review of medication adherence, with particular focus on gout patients. Adherence rates may vary according to methods used to measure adherence. Overall, synthesis of current evidence suggest that medication non-adherence is substantial in gout. Findings highlight the importance of discussing adherence with gout medications during health care professional encounters with gout patients.

*medication adherence evaluated as exposure and not outcome