Anti-hypertensive medications and cardiovascular events in older adults with multiple chronic conditions

Abstract

Importance: Randomized trials of anti-hypertensive treatment demonstrating reduced risk of cardiovascular events in older adults included participants with less comorbidity than clinical populations. Whether these results generalize to all older adults, most of whom have multiple chronic conditions, is uncertain.

Objective: To determine the association between anti-hypertensive medications and CV events and mortality in a nationally representative population of older adults.

Design: Competing risk analysis with propensity score adjustment and matching in the Medicare Current Beneficiary Survey cohort over three-year follow-up through 2010.

Participants and setting: 4,961 community-living participants with hypertension.

Exposure: Anti-hypertensive medication intensity, based on standardized daily dose for each anti-hypertensive medication class participants used.

Main outcomes and measures: Cardiovascular events (myocardial infarction, unstable angina, cardiac revascularization, stroke, and hospitalizations for heart failure) and mortality.

Results: Of 4,961 participants, 14.1% received no anti-hypertensives; 54.6% received moderate, and 31.3% received high, anti-hypertensive intensity. During follow-up, 1,247 participants (25.1%) experienced cardiovascular events; 837 participants (16.9%) died. Of deaths, 430 (51.4%) occurred in participants who experienced cardiovascular events during follow-up. In the propensity score adjusted cohort, after adjusting for propensity score and other covariates, neither moderate (adjusted hazard ratio, 1.08 [95% CI, 0.89-1.32]) nor high (1.16 [0.94-1.43]) anti-hypertensive intensity was associated with experiencing cardiovascular events. The hazard ratio for death among all participants was 0.79 [0.65-0.97] in the moderate, and 0.72 [0.58-0.91] in the high intensity groups compared with those receiving no anti-hypertensives. Among participants who experienced cardiovascular events, the hazard ratio for death was 0.65 [0.48-0.87] and 0.58 [0.42-0.80] in the moderate and high intensity groups, respectively. Results were similar in the propensity score-matched subcohort.

Conclusions and relevance: In this nationally representative cohort of older adults, anti-hypertensive treatment was associated with reduced mortality but not cardiovascular events. Whether RCT results generalize to older adults with multiple chronic conditions remains uncertain.

Figure 1. 3-year cumulative incidence of cardiovascular events according to anti-hypertensive intensity in older adults with hypertension.

Legend: The cumulative incidence was estimated using a subdistribution hazards regression model, with the cardiovascular events as the primary outcome and mortality among participants with no primary CV event during follow-up as the competing outcome. Follow-up period was three years. Anti-hypertensive intensity was trichotomized into no anti-hypertensive use, moderate anti-hypertensive intensity, and high anti-hypertensive intensity as defined in the Methods. The variables included in the propensity score are noted in Table 1. The model adjusted for year of study entry, propensity score as a continuous variable, age, gender, prior myocardial infarction, prior stroke, heart failure, diabetes atrial fibrillation, valvular heart disease, renal disease, current smoking status, statin use, difficulty walking, obesity, depression, cognitive impairment, number of non-antihypertensive medications, self-perceived health, blood pressure taken within past six month. Vertical line (Y Axis) represents cumulative incidence probability (%); horizontal line (X Axis) represents time in days from study entry to onset of first cardiovascular event.