The U-shaped association between achieved blood pressure and risk of cardiovascular events and mortality in elderly and younger patients

OBJECTIVE: The main objective is to assess the appropriate level of achieved SBP and DBP to prevent cardiovascular events. METHODS: We used the National Sample Cohort from the National Health Insurance Service in Korea and analyzed data of 44 462 hypertensive patients aged 20--84 years. Achieved SBP and DBP were categorized according to average achieved SBP (<120, 120-129, 130-139, 140-149, and ≥150 mmHg) and DBP (<70, 70-79, 80-89, 90-99, and ≥100 mmHg). We examined the association between achieved BP and composite outcome including cardiovascular death, admission of stroke, myocardial infarction, or heart failure, and all-caused death in elderly aged more than 65 years and in younger patients. RESULTS: After a median follow-up of 6.8 years, achieved SBP less than 120 mmHg and at least 150 mmHg in elderly and younger patients, respectively, were significantly associated with a higher risk of composite outcome than achieved SBP of 120-129 mmHg. Cox's proportional hazard analysis showed that the association between achieved SBP and risk of composite outcome and all-cause death had U-shaped relationships and identified a nadir of SBP of 135.6 and 128.9 mmHg, respectively, for composite outcome and 135.1 and 131.4 mmHg, respectively, for all-cause death in elderly and younger patients. CONCLUSION: Compared with SBP of 120-129 mmHg, not only low achieved SBP of less than 120 mmHg but also high BP are associated with risk of adverse cardiovascular event and all-cause death in both elderly and younger patients with a distinct U-shaped relationship.