Patient Characteristics Related To Medication Adherence In A Nationwide Pragmatic Trial Comparing Thiazide-type Diuretics

Background: Antihypertensive treatment (AHT) is crucial for preventing major adverse cardiovascular events and other negative health outcomes, but poor adherence remains a challenge. We assessed the associations between patient characteristics and adherence to two thiazide-type diuretics in a large sample of hypertensive patients from the Diuretic Comparison Project (DCP), a nationwide randomized pragmatic trial conducted in the Veterans Affairs Healthcare System. Methods: Study data, collected electronically during routine clinical care, were used to determine adherence to chlorthalidone and hydrochlorothiazide. Participants were classified as adherent (70.3%; 9,501 of 13,523) or non-adherent (29.7%; 4,022 of 13,523) based on a medication possession ratio threshold of 80%, irrespective of randomized drug assignment. Logistic regression was used to measure the associations. Results: Non-adherent participants were more likely to be older, Black, not married, residing in urban areas, current smokers, and had a higher level of baseline systolic blood pressure (Table 1). History of cardiovascular disease and diabetes were associated with lower adherence. However, participants with higher BMI and those who received more antihypertensive drugs showed better adherence than those with lower levels. Conclusion: These findings contribute to the identification of several patient characteristics as predictors of lower medication adherence. DCP’s pragmatic nature allowed for real-world data capture and may be useful to inform clinicians of patient groups who may not adhere to their medication and who might benefit from targeted interventions.