Antihypertensive Medication Adherence and Risk of Cardiovascular Disease Among Older Adults: A Population‐Based Cohort Study

Abstract

BackgroundAntihypertension medication (antihypertensive) adherence lowers risk of cardiovascular disease (CVD); few studies have examined this association among older adults.Methods and ResultsWe assessed this association among Medicare fee‐for‐service beneficiaries aged 66 to 79 years who were newly diagnosed with hypertension and initiated on antihypertensives in 2008–2009 (n=155 597). We calculated proportion of days covered (PDC) during follow‐up, using proportional subdistribution hazard models, to examine association between antihypertensive adherence and a composite CVD outcomes, including first incident of fatal/nonfatal acute myocardial infarction, ischemic heart disease, stroke/transient ischemic attack, and heart failure. During follow‐up (median 5.8 years and 798 621 person‐years), we documented 47 198 CVD events. Among beneficiaries, 60.8%, 30.3%, and 8.9% had PDC ≥80%, 40% to 79%, and <40%. Crude incidence of CVD events were 40.1 (95% CI, 40.0–40.1), 93.9 (93.8–93.9), and 98.1 (98.1–98.2) per 1000 person‐years for PDC ≥80%, 40% to 79%, and <40%, respectively. Adjusted hazard ratios for CVD events were 1.0 (<40% as reference), 1.0 (0.97–1.03) for 40% to 79%, and 0.44 (0.42–0.45) for ≥80% (P<0.001). Dose‐response analysis suggested a nonlinear relationship between PDC and risk for CVD events with a protective effect of ≥80%. The pattern of associations between PDC and ischemic heart disease, stroke/transient ischemic attack, and heart failure were largely consistent as for CVD events and across different groups.ConclusionsAntihypertensive adherence was associated with a significantly lower risk of CVD events among older adults. There appeared to be a threshold effect in reducing CVD events at around PDC 80%, above which the risk for CVD reduced substantially.

The association between medication non‐adherence and adverse health outcomes in ageing populations: A systematic review and meta‐analysis

“…The included studies focussed on a wide range of disease areas including pulmonary diseases, osteoporosis, depression, cardiovascular diseases, Parkinson's disease, epilepsy, chronic kidney disease, cancer and diabetes mellitus . Two studies did not measure disease‐specific medication (non‐)adherence .…”

“…Two studies did not measure disease‐specific medication (non‐)adherence . Thirty‐six studies were specific to, or provided age stratified analysis for people aged ≥64 years, while the other 30 studies also included middle aged adults (≥50 years) . Thirteen authors of the included texts were contacted via e‐mail for further information, and 8 replied.…”

“…Thirteen authors of the included texts were contacted via e‐mail for further information, and 8 replied. In terms of adherence measurement, 54 studies measured medication (non‐)adherence using pharmacy claims data while 11 studies used self‐report methods, consisting of the 4‐item or 8‐item Morisky Medication Adherence Scale, or self‐reported PDC and MEMs was used in 4 studies …”

“…Overall, 48 studies were determined to be high quality, 17 were determined to be medium quality and 1 study was deemed to be low quality (Table S8). There was considerable variability with regards to external validity (generalisability), with 15 studies deemed medium quality and 11 studies achieving low quality .…”

Statin Adherence and Mortality in Patients Aged 80 Years and Older After Acute Myocardial Infarction

“…We calculated the proportion of days covered (PDC) over the entire 365 days using dates and days of supply of the prescription filled. Adherence level was classified as high (PDC 80% or higher), partial (PDC 40% or higher and lower than 80%), and low (PDC lower than 40%) . PDC is used by the Centers for Diseases Control and Prevention and the Centers for Medicare and Medicaid Services as a quality metric.…”