Optimal blood pressure control in treated hypertensive patients. Report from the Department of Health Hypertension Care Computing Project (DHCCP).

BACKGROUND: We wished to determine the range of treated systolic (SBP) and diastolic blood pressure (DBP) associated with the best survival in hypertensive patients.

METHODS AND RESULTS: We conducted a cohort study of patients enrolled in the DoH Hypertension Care Computer Project. Five specialist hypertension clinics (95% of patients) and general practitioners (5%) followed 6214 patients (3070 men and 3144 women) with an average age of 52 years for a mean of 107 months. Total, cardiovascular, ischemic heart disease, (IHD) and stroke mortality were the outcome measures. Age-adjusted relative hazard rates were calculated giving the effect on mortality of systolic or diastolic pressure being higher by 1 mm Hg. In men the optimal level of SBP for all four measures of mortality was the lowest pressure range observed, 92 to 133 mm Hg (median 127). For women the treated SBP range of 96 to 148 mm Hg (median 137) was associated with a low total mortality and also with low to moderate rates for IHD and stroke mortality. Relative hazard rates (P < .001) for IHD mortality were 1.010 for men and 1.013 for women and for stroke mortality were 1.018 and 1.021, respectively. The results were similar in men under and over the age of 60. SBP and DBP tended to be more important in younger than older women. For treated DBP in men, a pressure of 55 to 94 mm Hg (median 87) was associated with a low total mortality. The lowest stroke mortality in men was observed for a DBP range of 55 to 83 mm Hg (median 80) but with a tendency for an increase in IHD mortality. For women DBP < 95 mm Hg (range 55 to 94, median 87) also was associated with a low total mortality. IHD mortality in women was not closely related to treated DBP, relative hazard rate = 1.003, [95% confidence index (CI); 0.990,1.017] but the relative hazard rate for men was 1.011, (95% CI; 1.000, 1.022). The relative hazard rates for treated DBP and stroke were high at 1.035 and 1.028 for men and women, respectively (P < .001). IHD mortality increased in the one third of patients with the greatest fall in DBP on treatment, provided they were not initially in the one-third group with highest untreated DBP.

CONCLUSIONS: The best overall survival was associated with a treated SBP of < 134 mm Hg in men and < 149 mm Hg in women and a treated DBP of < 95 mm Hg.