Natural history of borderline hypertension in the Hisayama community, Japan--I. The relative prognostic importance of transient variability in blood pressure.

Long-term prognosis of borderline hypertensives was studied in a prospective population survey carried on since 1961 in the town of Hisayama, Japan. Five consecutive BP recordings on 1621 subjects aged 40 and over were obtained at entry, and the variability in BP between the first and fifth readings was taken into account when classifying the subject into categorical groups. Even with an estimated variability in BP in several measurements on one occasion, a large fluctuation in BP was observed in both the borderline hypertensives and the normotensives. Borderline hypertensives with a transient elevation in BP more frequently died from cardiovascular disease than did those without BP elevation, as estimated by the long-term cumulative mortality. However, there was no difference in the frequency of hypertension-related organ damage between these two groups at entry.