Abstract 14517: Adaptive Cluster Analysis of Individual Patient Level Adherence From Electronically Monitored Medication Adherence Predicts Hospitalization Rates in Heart Failure Patients
Background: Electronic monitoring (EM) of medication use is the gold standard measure of medication adherence with the capacity to explore patient’s patterns of medication taking over time. However, the majority of studies used mean medication adherence rates from EM that does not capture whether patients over- or under-medicate over time.
Objective: To identify individual patient adherence patterns over time, cluster these into adherence types, and relate adherence types to hospitalization rates during monitoring and follow-up periods combined.
Method: Medication adherence was assessed using the Medication Event Monitoring system. Hospitalizations were obtained by patient interview and hospital database review. Adaptive Poisson regression was used to generate possibly nonlinear adherence patterns over time for both mean adherence and adherence variability. Adaptive cluster analysis was used to identify an appropriate clustering procedure and number of clusters with at least 10% of patients in each cluster. Adaptive Poisson regression identified the best combination of adherence clusters for predicting hospitalization rates.
Results: EM adherence data were available for 134 patients (age 61±11 yrs; 70% male; married 61%) over monitoring periods of 39-197 days excluding hospitalizations. Hospitalization occurrence was available for monitoring + follow-up periods of 3-44 months. Five adherence clusters (1-5) were identified (centroids plotted) for mean (Fig 1) and variability (Fig 2). We group these 5 clusters into: 1) highly consistent adherence (Cluster 1-2) and 2) highly inconsistent adherence (Cluster 3-5). Patients with highly consistent adherence (high mean adherence and low or very low adherence variability) were more likely (p<.001) to have lower hospitalization rates (42% lower with 95% CI 31%-58%).
Conclusion: Highly consistent medication adherence is a protective factor for reduced hospitalization rates for heart failure patients.
Author Disclosures: J. Wu: None. G. Knafl: None. D.K. Moser: None.
- © 2016 by American Heart Association, Inc.