Background: Previous studies of the risk associated with high-normal blood pressure (BP) determined BP category in a cross-sectional fashion.
Methods: In 1982-1984, we measured BP in a random sample of 2357 Danes without previous cardiovascular complications, aged 30 to 60 years. We determined progression from optimal (<120/80 mm Hg), normal (120 to 129/80 to 84 mm Hg), and high-normal (130 to 139/85 to 89 mm Hg) BP to hypertension (>or=140/90 mm Hg or start of antihypertensive treatment) by follow-up until 1993-1994. We studied the prognostic significance of progression by subsequent follow-up until 2003.
Results: During 10.9 years (median), the crude progression rates to hypertension from optimal, normal, and high-normal BP were 10.4%, 37.3%, and 58.1%, respectively. During an additional 9.4 years (median), 218 first cardiovascular end points (cardiovascular death, nonfatal stroke, and nonfatal coronary heart disease) occurred. With sustained optimal or normal BP as reference, the multivariate-adjusted hazard ratios were similar (P > .60) for progression to high-normal BP (1.57; 95% confidence interval [CI], 1.06-2.33), for progression to hypertension (1.64; 95% CI, 1.19-2.26), and for sustained high-normal BP or hypertension (1.78; 95% CI, 1.39-2.29). The absolute 10-year cardiovascular risks were 5.1% for optimal or normal BP without progression, 11.1% and 13.9% for progression to high-normal BP or hypertension, respectively, and 18.7% for sustained high-normal BP or hypertension.
Conclusions: Progressing from optimal or normal BP to high-normal BP or hypertension carries nearly the same risk as sustained high-normal BP or hypertension.