Predictive value of the residual cholesterol inflammation index for heart failure risk: A cross-sectional study from NHANES

The residual cholesterol inflammation index (RCII) integrates residual cholesterol and C-reactive protein to assess for metabolic and inflammatory risk. We explored the link between the RCII and long-term risk of heart failure (HF) development in the United States. Data from the National Health and Nutrition Examination Survey were inspected, and 6027 participants aged 45 years and older were included. Natural log-transformed residual cholesterol inflammation index (ln RCII) values were used to classify participants into quartiles. The association between RCII and HF risk was examined, and potential covariates were controlled for using subgroup analyses, restricted cubic spline curves, subject work characteristic curve analysis techniques, and logistic regression models. The Q4 group (ln RCII > 14.82) was older, had an elevated body mass index, and a notably increased occurrence of diabetes, hypertension, and HF than the low ln RCII group ( P < .05). Corrected logistic regression showed a higher HF in the Q4 group compared to the Q1 group ( P < .05). HF risk increased by 36% ( P < .001), 34% ( P < .001), and 22% ( P = .009) for every unit increase in ln RCII, indicating an independent positive correlation between RCII and HF risk. Restricted cubic spline regression confirmed a linear relationship (nonlinear P > .05). The receiver operating characteristic curve area under the curve was 0.59 ( P < .05). Subgroup analyses revealed significant moderating associations for smoking status (interaction P = .034), stronger predictive validity of ln RCII among nonsmokers ( P = .0014), no significant associations among smokers ( P = .2375), and consistent positive associations for other subgroups. Elevated RCII levels are predictive of HF risk and are linked to an increased risk of HF in middle-aged and older populations.