Association of the nutritional risk index for Japanese hemodialysis patients with long-term mortality: The Q-Cohort Study

Background: Protein-energy wasting (PEW) is a risk factor for mortality in patients undergoing hemodialysis. Recently, a nutritional risk index for Japanese hemodialysis patients (NRI-JH) has been proposed as a surrogate index of PEW. However, no study has determined the association of the NRI-JH with long-term mortality in patients undergoing hemodialysis. Furthermore, the validity of the NRI-JH has not been confirmed. Methods: In total, 3046 patients undergoing hemodialysis and registered in the Q-Cohort Study were followed up for 10 years. The NRI-JH was calculated on the basis of body mass index and serum levels of albumin, total cholesterol, and creatinine. The patients were divided into four groups according to the NRI-JH scores: 0–3 (G1, n = 1343), 4–7 (G2, n = 1136), 8–10 (G3, n = 321), and 11–13 (G4, n = 246). We examined the association between the NRI-JH and the 4-year and 10-year risks of all-cause, cardiovascular, and infection-related deaths using the Cox proportional hazards model. Results: During the follow-up period, 647 patients died during the first 4 years, and 1503 patients died within 10 years. The 4-year prognosis was analyzed and compared with the lowest NRI-JH score group. Multivariable-adjusted hazard ratios (95% confidence intervals) for all-cause death were 1.93 (1.57–2.38), 2.68 (2.05–3.50), and 3.16 (2.40–4.16) in the G2, G3, and G4 groups, respectively. Similarly, a higher NRI-JH score was associated with an increased risk of cardiovascular and infection-related deaths. Conclusion: A higher NRI-JH score was associated with an increased risk of long-term mortality in patients undergoing maintenance hemodialysis. Trial registration: The study protocol was registered in the University Hospital Medical Information Network (UMIN) clinical trial registry (UMIN ID: 000000556).