Stroke risk and antihypertensive drug treatment in the general population: the Japan arteriosclerosis longitudinal study

Objective To evaluate the association between stroke risk and blood pressure (BP) levels with regards to the usage of antihypertensive medications. Methods 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. Results 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. Conclusion 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. Hypertens 27:357-364 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.