Nutritional Risk Index for Japanese Hemodialysis Patients, protein-energy wasting, and mortality associations in patients undergoing hemodialysis

The associations between the Nutritional Risk Index for Japanese Hemodialysis Patients (NRI-JH) score, protein-energy wasting (PEW), and mortality in patients undergoing hemodialysis remain unclear. We investigated the associations among the NRI-JH score, PEW, and all-cause death in patients undergoing hemodialysis. We retrospectively enrolled 263 patients on maintenance hemodialysis for more than 6 months. PEW was diagnosed using the simple PEW score. We determined the optimal NRI-JH cutoff score for diagnosing PEW from the receiver operating characteristic curve analysis. We divided patients into two groups using the cutoff and followed up on mortality. The NRI-JH score and simple PEW score were significantly correlated (ρ = 0.581, p < 0.0001). The NRI-JH scores were notably higher for patients with PEW (median 8 [interquartile range (IQR) 5–9], N = 94) than for those without PEW (median 4 [IQR 1–7], N = 169) (p < 0.0001). The optimal NRI-JH score cutoff was 8 (area under the curve 0.776, sensitivity 0.617, specificity 0.841; p < 0.0001). During the follow-up period, 131 patients died. The 5-year survival rate was significantly lower in the group with NRI-JH scores ≥ 8 than in the group with scores < 8 (43.4% vs. 75.7%; p < 0.0001). A higher NRI-JH score was independently linked to an increased all-cause mortality risk (adjusted hazard ratio 1.98, 95% confidence interval 1.34–2.93; p = 0.0007). Moreover, adding the NRI-JH score to the baseline risk model significantly improved the net reclassification improvement (0.418, p = 0.00051). The optimal NRI-JH cutoff for diagnosing PEW in Japanese patients on hemodialysis was 8. Additionally, a higher NRI-JH score (≥ 8) was independently associated with a greater risk of all-cause mortality. Therefore, the NRI-JH may serve as both a marker of malnutrition and a predictor of mortality in these patients.