OS 22-09 Population-attributable risk of hypertension in development of Stroke: using the National Sample Cohort.

OBJECTIVE: Hypertension has been discussed as a key role in developing cardiovascular diseases. The stroke incidence is relatively high in South Korea compared to other countries. In our research, we quantified the impact of hypertension by estimating population attributable-risk in the development of stroke.

DESIGN AND METHOD: We selected 154,786 people aged over 40 among National Health Insurance Service-National sample cohort who have not diagnosed either stroke or TIA within baseline periods (2002-2005). We computed the incidence rate and the age-standardized incidence rate of stroke, and evaluated population attributable risk (PAR) using the multivariable Cox's regression analysis.

RESULTS: During follow-up periods, 7,772 patients were newly diagnosed with stroke (mean follow-up period 8.56 years, ± 1.72 years). The incidence of stroke was increased with increment of BP. The incidence was 380/100,000 person-years with no-hypertension, 632/100,000 person-years with pre-hypertension, 961/100,000 person-years with stage 1 hypertension, and 1,248/100,000 person-years with stage 2 hypertension. Hypertension has PAFs of 22% (95% CI 0.19∼0.25) for stroke, and followed by diabetes mellitus 9% (95% CI 0.07∼0.11), and inactive lifestyle 7% (95% CI 0.04∼0.10). As expected, age has highest PAFs among the risk factors 47% (95% CI 0.36∼0.57).

CONCLUSIONS: Hypertension has high PAFs for stroke among the modifiable risk factors, and the risk was increased with BP elevation. Therefore, active management of BP has a substantial impact on population health.