Background: Subjects with prehypertension (pre-HT; 120/80 to 139/89 mm Hg) have an increased risk of cardiovascular disease (CVD); however, whether the risk of pre-HT can be seen at the pre-HT status or only after progression to a hypertensive (HT; ≥140/90 mm Hg) state during the follow-up period is unknown.

Methods: The Jichi Medical Cohort study enrolled 12,490 subjects recruited from a Japanese general population. Of those, 2227 subjects whose BP data at baseline and at the middle of follow-up and tracking of CVD events were available (median follow-up period: 11.8 years). We evaluated the risk of HT in those with normal BP or pre-HT at baseline whose BP progressed to HT at the middle of follow-up compared with those whose BP remained at normal or pre-HT levels.

Results: Among the 707 normotensive patients at baseline, 34.1% and 6.6% of subjects progressed to pre-HT and HT, respectively, by the middle of follow-up. Among 702 subjects with pre-HT at baseline, 26.1% progressed to HT. During the follow-up period, there were 11 CVD events in normotensive patients and 16 CVD events in pre-HT patients at baseline. The subjects who progressed from pre-HT to HT had 2.95 times higher risk of CVD than those who remained at normal BP or pre-HT in a multivariable-adjusted Cox hazard model.

Conclusion: This relatively long-term prospective cohort study indicated that the CVD risk with pre-HT might increase after progression to HT; however, the number of CVD events was small. Therefore, the results need to be confirmed in a larger cohort.