Background
Many studies have examined the multiple correlates of non-adherence in Blacks. However, they are largely cross-sectional thus; these studies are unable to examine their predictive value on long-term medication adherence.
Purpose
To examine the predictive role of key psychosocial and interpersonal factors on changes in medication adherence over a one-year period.
Methods
Data were collected from 815 Black patients with hypertension followed in community health centers. Hypothesized predictor variables included self-efficacy, depressive symptoms, social support, and patient-provider communication measured at baseline, 6- and 12-months. The dependent variable, medication adherence was assessed at baseline, 6- and 12-months. Latent Growth Modeling was used to evaluate the pathways between the latent predictor variables and medication adherence.
Results
Participants were mostly female, low-income, with high school education or less, and mean age of 57 years. At baseline, high self-efficacy was associated with low depressive symptoms (β=−.22, p=0.05), collaborative patient-provider communication (β=.17, p=0.006), and better medication adherence (β=1.04, p<0.001). More social support and collaborative patient-provider communication were associated with low depressive symptoms (β=−.08, p=0.02; β=−.18, p=0.01). More social support was positively associated with collaborative patient-provider communication (β=.32, p<0.001). In the longitudinal model, increasing self-efficacy over time predicted improvements in medication adherence one year later (β=1.76, p<0.001; CFI=0.95; RMSEA=0.04; SRMR=0.04; Chi-Squared Index of Model Fit=1128.54).
Conclusions
Self-efficacy is a key predictor of medication adherence over time in Black patients with hypertension. Initial levels of self-efficacy are influenced by the presence of depressive symptoms as well as the perceived quality of patient-provider communication.