Social Determinants of Health Reveal Heterogeneity in Associations Between <scp>AHA PREVENT</scp> Cardiovascular Disease Risk Equations and Mortality and Provide Incremental Discrimination for Mortality in US Adults

BACKGROUND: The American Heart Association (AHA) PREVENT equations provide contemporary estimates of 10-year cardiovascular disease (CVD) risk. Although PREVENT was developed to estimate incident CVD risk, its relation to subsequent mortality in nationally representative US adults has not been well characterised. It also remains unclear whether social determinants of health (SDOH) modify these associations and improve discrimination beyond PREVENT. METHODS: Adults aged 40-75 years in NHANES 2003-2018 were linked to the National Death Index through December 31, 2019. SDOH burden was derived by summing 8 unfavourable SDOH components and categorised as 0, 1-2, 3-4 or ≥ 5. Survey-weighted Cox models were used to evaluate associations with all-cause and cardio-cerebrovascular disease (CCD) mortality, defined as a composite of cardiovascular and cerebrovascular mortality. Effect modification was assessed using multiplicative interaction terms. Incremental discrimination after adding SDOH to PREVENT was evaluated using time-dependent receiver operating characteristic (ROC) curves. RESULTS: Among 18 694 adults (mean age, 54.3 years; 52.6% women), 1646 all-cause deaths and 392 CCD deaths occurred over a median follow-up of 8.2 years (IQR, 4.3-12.3). In multivariable models, each 5-percentage-point higher PREVENT-estimated risk was associated with higher all-cause mortality (HR = 1.55; 95% CI, 1.47-1.64) and CCD mortality (HR = 1.62; 95% CI, 1.52-1.74). Heterogeneity by SDOH burden was demonstrated (p for interaction < 0.001 for both outcomes), with stronger associations in the 0-unfavourable group (all-cause: HR = 2.01; 95% CI, 1.79-2.25; CCD: HR = 2.35; 95% CI, 1.91-2.88) and attenuated associations in the ≥ 5-unfavourable group (all-cause: HR = 1.38; 95% CI, 1.26-1.50; CCD: HR = 1.46; 95% CI, 1.31-1.62). At 10 years, discrimination improved after adding SDOH to PREVENT (all-cause AUC: 0.747 to 0.778; p < 0.001; CCD AUC: 0.790 to 0.812; p = 0.042). CONCLUSIONS: SDOH burden was associated with graded mortality and modified the strength of the association between PREVENT-estimated 10-year CVD risk and mortality. Adding SDOH modestly improved mortality discrimination beyond PREVENT alone, supporting incorporation of social risk in risk stratification.