Altered blood pressure progression in the community and its relation to clinical events

Background: Long-term blood pressure (BP) progression and its importance as a predictor of clinical outcome have not been well characterized across different periods. Methods: We evaluated period trends for 3 BP variables (long-term slope and mean BP during a baseline period of 16 years, and last baseline value) in an earlier period (1953-1971; n=1644, mean participant age, 61 years) and in a later period (1971-1990; n=1040, mean participant age, 58 years) in participants in the Framingham Heart Study who initially did not have hypertension. In addition, we explored the relation of BP to cardiovascular disease incidence and all-cause mortality in the 2 periods, each with up to 16 years of follow-up. Results: Long-term slope, mean, and last baseline BP measurements were significantly lower in the later period (P<.001). Rates of hypertension control (BP <140/90 mm Hg) were higher in the later vs the earlier period (32% vs 23%; P<.001). Multivariate hazard ratios for the relation of BP to outcomes were generally lower in the later period; this was statistically significant for the relation of last baseline BP to all-cause mortality (hazard ratio for 1-SD increase in systolic BP, 1.02 vs 1.25, P=.03; hazard ratio for diastolic BP, 1.00 vs 1.23, P=.04). Conclusions: We found evidence that BP levels in the community have changed over time, coinciding with improved rates of hypertension control and attenuation of BP-mortality relations. These findings are consistent with the hypothesis that hypertension treatment in the community has altered the natural history of BP progression and its relation to clinical outcome.