Medication adherence for resistant hypertension: Assessing theoretical predictors of adherence using direct and indirect adherence measures.

Associations among unique adherence measures were weak overall, providing further evidence that multiple measures are necessary to accurately assess adherence. Habit strength is a key predictor of adherence for chronic conditions. Both habit strength and pill burden represent important intervention targets for improving long-term medication adherence. Longitudinal inception studies are needed to properly test Common-Sense Model propositions and elucidate the role of beliefs, coherence, and habits in predicting adherence at various stages of the chronic illness trajectory. Statement of contribution What is already known on this subject? Non-adherence to antihypertensives is a leading cause of apparent treatment-resistant hypertension (aTRH). Behaviour maintenance (vs. initiation) factors may be more predictive of long-term adherence. What does this study add? Associations among direct and indirect measures of adherence are generally weak. Habit strength is the strongest predictor of long-term adherence for aTRH in primary care. Inception studies are needed to further validate Common-Sense Model propositions.