Cardiovascular medication utilization and adherence among adults living in rural and urban areas: a systematic review and meta-analysis

BACKGROUND Rural residents face numerous barriers to healthcare access and studies suggest poorer health outcomes for rural patients. Therefore we undertook a systematic review to determine if cardiovascular medication utilization and adherence patterns differ for rural versus urban patients. METHODS A comprehensive search of major electronic datasets was undertaken for controlled clinical trials and observational studies comparing utilization or adherence to cardiovascular medications in rural versus urban adults with cardiovascular disease or diabetes. Two reviewers independently identified citations, extracted data, and evaluated quality using the STROBE checklist. Risk estimates were abstracted and pooled where appropriate using random effects models. Methods and reporting were in accordance with MOOSE guidelines. RESULTS Fifty-one studies were included of fair to good quality (median STROBE score 17.5). Although pooled unadjusted analyses suggested that patients in rural areas were less likely to receive evidence-based cardiovascular medications (23 studies, OR 0.88, 95% CI 0.79, 0.98), pooled data from 21 studies adjusted for potential confounders indicated no rural-urban differences (adjusted OR 1.02, 95% CI 0.91, 1.13). The high heterogeneity observed (I(2) = 97%) was partially explained by treatment setting (hospital, ambulatory care, or community-based sample), age, and disease. Adherence did not differ between urban versus rural patients (3 studies, OR 0.94, 95% CI 0.39, 2.27, I(2) = 91%). CONCLUSIONS We found no consistent differences in rates of cardiovascular medication utilization or adherence among adults with cardiovascular disease or diabetes living in rural versus urban settings. Higher quality evidence is needed to determine if differences truly exist between urban and rural patients in the use of, and adherence to, evidence-based medications.