A new nutritional risk index for predicting mortality in hemodialysis patients: Nationwide cohort study

BACKGROUND: Protein energy wasting (PEW) is a risk factor for death. However, the cutoff vales for PEW are not optimized for early identification of hemodialysis patients with malnutrition. We evaluated the prognosis of Japanese maintenance hemodialysis patients using nutritional indices optimized for them. MATERIALS AND METHODS: We analyzed data from a nation-wide prospective cohort study of the Japanese Society for Dialysis Therapy Renal Data Registry to develop and validate a nutritional risk index (n = 48349, 48349, respectively). The association of nutritional factors with one-year death was tested using Cox proportional hazards models. Their cutoff levels were determined from the hazard ratios or receiver operating characteristic curves. Then, risk index was developed using scoring models. RESULTS: Male was 61.4%; average age, 65.7±12.2 years; and diabetes mellitus, 32.8%. Four clinical factors were retained in the final model: low BMI (<20kg/m(2)), yes = 3, no = 0; low serum albumin level (young <3.7g/dL; old <3.5g/dL), yes = 4, no = 0; abnormal serum total cholesterol level, low (<130mg/dL) = 1, high (220≥mg/dL) = 2, no = 0; low serum creatinine level (young female, <9.7mg/dL; old female, <8.0mg/dL; young male, <11.6mg/dL; old male, <9.7mg/dL), yes = 4, no = 0. In the validation dataset, medium- and high-risk groups (total score 8 to 10; 11 or more) showed a higher risk of all-cause death than the low-risk group (0 to 7): medium-risk group (10.5%), hazard ratio adjusted for baseline characteristics 1.96 (95% confidence interval 1.77, 2.16); high-risk group (8.2%), 3.91 (3.57, 4.29). The medium- and high-risk groups also showed a higher risk of cardiovascular disease- and infection-caused deaths than the low-risk group. CONCLUSION: We developed a new nutritional risk index for hemodialysis patients, which may detect patients with malnutrition with a high-risk of death.