Restricted cubic spline curve showing adjusted hazard ratios (solid line) and 95% confidence intervals (95% CIs) (dashed lines) for cardiovascular-related mortality associated with serum NEFA concentration. Covariates include age, body mass index, smoking status, physical activity, cardiovascular history, hypertension, diabetes mellitus, plasma triglycerides, cholesterol and lipid medication, C-reactive protein, eGFR, and urinary albumin excretion rate.