To evaluate the association between stroke
risk and blood pressure
(BP) levels with regard to the usage of antihypertensive medications.
From the Japan arteriosclerosis longitudinal study, 11 371 participants from the four population-based cohort studies (aged 40–89) were followed up for a mean of 9.5 years. A Poisson regression model, adjusting for possible confounding factors, was used to investigate the risk of first stroke
among six BP-based categories (BP defined according to recent guidelines), in relation to the use of antihypertensive medications.
There were 324 incident cases of first stroke
. Among untreated groups, the relative hazard increased linearly with the elevation of BP grade (trend P
= 0.0001). The untreated group with normal BP had a significantly higher stroke
risk [relative hazard 2.09, 95% confidence interval 1.09–4.01] than the untreated group with optimal BP. There was no stepwise increase in stroke
risk observed among treated groups (trend P
= 0.1). The stroke
risk among treated groups, even among those with optimal BP (relative hazard 4.10, 95% confidence interval 1.17–14.4), was significantly higher than that in the untreated groups with the same BP level.
Treated individuals with optimal BP had a higher stroke
risk than untreated ones with optimal BP. Healthcare providers need to be vigilant for residual cardiovascular risks in treated hypertensive patients.