Prehypertension and incident acute coronary heart disease in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.

Abstract

The independent prognostic value of prehypertension for incident coronary heart disease (CHD) remains unsettled. We examined associations between prehypertension (systolic blood pressure of 130-139.9 and/or diastolic blood pressure of 80-89mm Hg) and incident acute CHD and cardiovascular disease (CVD) death. The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study includes 30,239 black and white community-dwelling adults aged ≥45 years recruited from 2003 to 2007. Endpoints were centrally adjudicated by experts and included incident nonfatal myocardial infarction (MI), acute CHD (nonfatal and fatal MI), and a composite of nonfatal MI or CVD death. Cox proportional hazards models estimated the hazard ratios (HRs) for these endpoints by blood pressure (BP) categories adjusting for sociodemographics and CHD risk factors. The 24,388 participants free of CHD at baseline (mean age = 64.1±9.3 years; 58% women; 42% blacks) were followed for a mean of 4.2±1.5 years. The unadjusted HR for incident acute CHD was 1.23 (95% confidence interval (CI) = 0.93-1.64) for prehypertension and 2.28 (95% CI = 1.71-3.04) for hypertension. With full adjustment, the HR for prehypertension remained nonsignificant. The HR for nonfatal MI and for acute CHD death was also nonsignificant. For the combined endpoint (incident fatal and nonfatal MI or CVD death), the unadjusted HR was 1.29 (95% CI = 1.02-1.64) but the adjusted HR was 1.15 (95% CI = 0.91-1.47). Finally, after adjustment for other CHD risk factors, there was no significant interaction of BP with race. In this sample, prehypertension was not associated with incident acute CHD.