Abstract P342: Predicting Low Pharmacy Refill Adherence in Elderly Patients with Uncontrolled Blood Pressure
Background: Parsimonious self-report tools predicting pharmacy refill in patients with uncontrolled blood pressure could facilitate hypertension management in the elderly. We developed and evaluated a short self-report tool to predict low adherence via pharmacy refill in older patients with uncontrolled hypertension.
Methods: Cross-sectional analyses of survey and administrative data from the Cohort Study of Medication Adherence among Older Adults (CoSMO) were conducted on 394 adults with uncontrolled blood pressure. We considered 164 self-reported candidate items for development of a prediction rule for low (<0.8) vs. high (≥0.8) medication possession ratio (MPR) from pharmacy refill data. Risk prediction models were evaluated using best subsets analyses, and the final model was chosen based on clinical relevance and model parsimony. Bootstrap simulations assessed internal validation. The performance of the final model was compared to the 8-item Morisky Medication Adherence Scale (MMAS-8) and the 9-item Hill-Bone Compliance Scale.
Results: Participants were 33.0% black (130 of 394), 66.0% women (260 of 394), 23.4% with low MPR (92 of 394), and mean age of 76.6 ± 5.6 years. A 4-item self-report tool predicting pharmacy refill adherence showed moderate discrimination (C-statistic = 0.704, 95% CI = 0.683, 0.714) and good model fit (Hosmer-Lemeshow x2 P= 0.743). Sensitivity and specificity were 67.4% and 67.8%, respectively. The C-statistics for MMAS-8 and the Hill-Bone Compliance Scale were 0.665 (95% CI =0.632, 0.683) and 0.660 (95% CI = 0.622, 0.674), respectively.
Conclusion: A 4-item self-report tool moderately discriminated low from high pharmacy refill adherers, and its test performance was comparable to existing 8- and 9-item adherence scales. Parsimonious tools to identify low adherers among patients with uncontrolled blood pressure may facilitate tailoring of interventions to improve blood pressure control in the elderly.
- © 2013 by American Heart Association, Inc.