The Effect Modification of Systolic Blood Pressure on the Association of Frailty and Cardiovascular Disease in Community-Dwelling Adults.

Frailty has been increasingly recognized as an important predictor of cardiovascular disease (CVD) risk; however, the modifying role of systolic blood pressure (SBP) in this association remains unclear. Using data from the China Health and Retirement Longitudinal Study, we included 7210 community-dwelling adults aged ≥45 years and assessed frailty status using a constructed frailty index. Participants were stratified according to SBP levels, and incident CVD events were ascertained during follow-up. Cox proportional hazards models were applied to evaluate the association between frailty and CVD risk, with SBP examined as an effect modifier. Over 53 531 person-years of follow-up, 1663 CVD events occurred. Frailty was consistently associated with a higher risk of CVD across all SBP strata. Each standard deviation increase in the frailty index was associated with a 28% higher CVD risk among participants with SBP <120 mmHg, a 54% higher risk among those with SBP 120-129 mmHg, and a 25% higher risk among those with SBP ≥130 mmHg. Joint analysis demonstrated that frail individuals with SBP 120-129 mmHg had the highest CVD risk (hazard ratio 3.40; 95% confidence interval 2.54-4.57). Sensitivity analyses confirmed a robust interaction between SBP and frailty in relation to CVD risk. These findings indicate that frailty substantially increases CVD risk across all SBP categories, with the greatest risk observed in frail individuals with high-normal SBP, suggesting that individualized blood pressure targets incorporating frailty status may optimize cardiovascular prevention rather than uniformly pursuing lower SBP levels.