Assessing the predictive power of nutritional indices on all-cause and cardiovascular mortality in hemodialysis patients: a longitudinal study

Background and HypothesisThe prognostic value of nutritional scoring tools in assessing the relationship between nutritional status and prognosis in hemodialysis patients is unclear. This multicenter retrospective cohort study compared the Prognostic Nutritional Index (PNI), Controlling Nutritional Status scores (CONUT), and Geriatric Nutritional Risk Index (GNRI) for predictive accuracy of all-cause and cardiovascular mortality, especially the impact of dynamic changes over time on prognosis.MethodsHemodialysis patients from four hospitals were included. Laboratory data and nutrition scores were collected at the initiation of dialysis, and at 6th, 12th, and 18th months after dialysis initiation. A joint model analyzed the relationship between dynamic nutritional scores and prognosis. Predictive values were assessed using the area under the curve (AUC).ResultsThe study included 863 patients with a median follow-up of 37 months. During the follow-up, 23.8% of patients died, with 14% attributed to cardiovascular causes. Malnourished patients demonstrated higher risks for all-cause and cardiovascular mortality. Dynamic changes in PNI and GNRI scores were significantly associated with reduced all-cause and cardiovascular mortality risks. Precisely, longitudinal increases in PNI and GNRI scores corresponded to a 4% and 3% reduction in all-cause (PNI: HR, 0.96; 95% CI, 0.95-0.98; GNRI: HR, 0.97; 95% CI, 0.96-0.98) and cardiovascular mortality risk (PNI: HR, 0.96; 95% CI, 0.94-0.98; GNRI: HR, 0.97; 95% CI, 0.95-0.98) respectively, with longer dialysis duration. Changes in CONUT scores were not significantly associated with either all-cause or cardiovascular mortality. The AUCs of the three joint models indicated that the GNRI score (0.893) possessed higher predictive accuracy for all-cause mortality compared to PNI (0.832) and CONUT (0.852). Similar trends were observed for cardiovascular mortality.ConclusionNutritional scores and their dynamic changes are intimately associated with mortality risk in hemodialysis patients. Compared to PNI and CONUT, the baseline GNRI and its post-dialysis variations demonstrate a superior predictive capability for all-cause and cardiovascular mortality in these patients.