Systolic blood pressure as an independent predictor of mortality in the Hypertension Detection and Follow-up Program

The Hypertension Detection and Follow-up Program (HDFP) findings demonstrate the predictive value of baseline systolic blood pressure (SBP) and of pulse pressure (PB) in five-year mortality from all causes. Grouping participants into four SBP strata revealed an approximately two-fold increase in age-adjusted mortality rate from SBP stratum I to SBP stratum IV. This effect remained after the contributions of other risk factors were controlled by multivariate analysis. In contrast, baseline diastolic blood pressure (DBP) had little demonstrable effect on mortality in this particular population. The predictive power of pulse pressure was similar to that of SBP. The group mean SBP of every stratum fell progressively during the trial, the change being of greater magnitude in the stepped care (SC) group than in the referred care (RC) group. Also, the reduction in all-cause mortality associated with SC treatment was observed at all levels of baseline SBP. An analysis using life table regression with SBP as a time-dependent variable showed that the postrandomization reduction in SBP was a significant factor in reducing mortality. Similarly, reduced DBP was also contributory. Prospective studies are required to answer definitively the question of the efficacy of treatment of systolic hypertension. Nevertheless, the present analysis of the HDFP data, despite design limitations, supports the advisability of reducing elevated systolic blood pressure.