Excess stroke among hypertensive men and women attributable to undertreatment of hypertension.

Background And Purpose: Most population-based studies indicate that a considerable proportion of hypertensive subjects are undertreated and that undertreatment is more prevalent among hypertensive men than among hypertensive women. The aim of our study was to investigate the consequences of undertreatment of hypertension for women and men in terms of stroke occurrence.

Methods: Approximately 45 000 men and women aged >/=20 years were examined in 2 population-based studies in the Netherlands. A cohort of 2616 hypertensive subjects (pharmacologically treated hypertensives and untreated hypertensives who needed pharmacological treatment according to the severity of their hypertension and the coexistence of additional cardiovascular risk factors) was selected for a follow-up study. Follow-up (mean duration, 4.6 years) was complete for 2369 (91%) of the enrolled hypertensive subjects.

Results: Compared with treated and controlled hypertensives, the relative risks of stroke for treated and uncontrolled hypertensives and for untreated hypertensives who needed treatment were 1.30 (95% CI, 0.70 to 2.44) and 1.76 (95% CI, 1.05 to 2.94), respectively. These relative risks and the prevalence of (undertreated) hypertension in the total population of 45 000 subjects were used to estimate the number of strokes in the Netherlands attributable to undertreatment. Among hypertensive men and women aged >/=20 years in the Netherlands, the proportions of strokes attributable to treated but uncontrolled blood pressure were 3.1% (95% CI, -5.2% to 18.7%) and 4.1% (95% CI, -7.2% to 20.7%), respectively. For untreated hypertensive men and women who should have been treated, these proportions were 22.8% (95% CI, 0.8% to 38.4%) and 25.4% (95% CI, 0. 5% to 42.5%), respectively.

Conclusions: Increasing the detection of hypertension and improving adherence to current guidelines might prevent a considerable proportion of the incident strokes among hypertensives. The potential impact of achieving control of blood pressure in patients already being treated on the reduction of strokes requires further investigation.