Comparative prognostic performance of nutritional, immune-inflammatory, and anthropometric indices for cardiovascular and all-cause mortality in older adults with cardiovascular disease (NHANES 2009–2018)

Background: Cardiovascular disease (CVD) in older adults is compounded by malnutrition and chronic inflammation. We compared the long-term prognostic performance of three categories of routinely available indices: nutritional (Prognostic Nutritional Index [PNI], Geriatric Nutritional Risk Index [GNRI], Controlling Nutritional Status [CONUT]); immune-inflammatory (Systemic Immune-Inflammation Index [SII]); and anthropometric (Weight-Adjusted Waist Index [WWI]). Methods: We analyzed 1,804 NHANES 2009-2018 participants aged ≥60 years with established CVD, linked to the National Death Index. Survey-weighted Cox models with restricted cubic splines estimated associations with cardiovascular and all-cause mortality, adjusted for demographic, socioeconomic, behavioral, and comorbid covariates. Sensitivity analyses included landmark exclusion of early deaths (6, 12, 24 months), a complete-case analysis, and additional adjustment for total energy and protein intake. Results: The nutritional indices (PNI, GNRI, CONUT) showed L-shaped associations with cardiovascular mortality that persisted after sequential exclusion of early deaths and after additional adjustment for total energy and protein intake. Each 1-point increase in PNI corresponded to an adjusted hazard ratio (aHR) of 0.91 (95% CI 0.87-0.95) for cardiovascular mortality; moderate-to-severe malnutrition by PNI carried a 4.61-fold higher hazard. PNI yielded the best model fit (lowest AIC/BIC); CONUT had the highest discrimination. The SII association attenuated when deaths within 24 months were excluded. The WWI predicted all-cause but not cardiovascular mortality. Conclusions: The nutritional indices (PNI, GNRI, CONUT) showed durable associations with cardiovascular mortality, whereas the SII signal was acute and the WWI predicted only all-cause mortality. These findings are hypothesis-generating; prospective external validation is required before routine clinical use.