Stroke risk in treated hypertension based on home blood pressure: the Ohasama study.
BACKGROUND
Several observational studies have shown that treated hypertensives are characterized as having worse prognosis than nonhypertensives. However, there is little evidence based on home blood pressure (home BP) measurement. We compare the risk of stroke between untreated individuals and those taking antihypertensive medication based on home BP and casual-screening BP (casual BP) in the general population.


METHODS
The study included 1,690 untreated and 700 treated subjects aged >or=35 years. We measured home BP and casual BP at the beginning of the study. The risk of first stroke was examined by using the Cox proportional hazards model.


RESULTS
During 11.9 years of follow-up, we observed 242 first-time stroke cases. Treated subjects had significantly higher risk for stroke than untreated subjects based on home BP (relative hazard (RH) = 1.48) as well as on casual BP (RH = 1.78), adjusted for systolic BP values and characteristics. When subjects were classified into six categories based on BP (optimal, normal, high normal, and grade 1-3 hypertension), RHs in treated hypertensives linearly increased (trend P < 0.01) based on home BP. However, there was no consistent association for casual BP (trend P: not significant) in treated subjects. Stroke risk was linearly increased regardless of the BP information source in untreated subjects (home BP: trend P < 0.01, casual BP: trend P < 0.01).


CONCLUSIONS
The results suggest a strong association between elevated home BP and increased risk of stroke. Home BP is a better tool to assess stroke risk, especially in treated hypertensives.
Yasui
Daisaku
D
Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences and Medicine, Sendai, Japan.
Asayama
Kei
K
Ohkubo
Takayoshi
T
Kikuya
Masahiro
M
Kanno
Atsuhiro
A
Hara
Azusa
A
Hirose
Takuo
T
Obara
Taku
T
Metoki
Hirohito
H
Inoue
Ryusuke
R
Totsune
Kazuhito
K
Hoshi
Haruhisa
H
Satoh
Hiroshi
H
Imai
Yutaka
Y
D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000188:drug therapy; D007564:Japan; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*
D000959:Antihypertensive Agents