The modulating effect of dietary protein intake on mortality in long-term hemodialysis patients: A nationwide population-based study

[[abstract]]AIMS OF THE STUDY: A high prevalence of protein-energy wasting and malnutrition among uremic patients is associated with an increase in morbidity and mortality. We aimed to investigate the modulating effect of daily dietary protein intake (DPI) evaluated by normalized protein catabolic rate (nPCR) on mortality in long-term hemodialysis (HD) patient from a nationwide population-based study. METHODS USED TO CONDUCT THE STUDY: By Taiwan Renal Registry Data System between 2005 and 2012, we divided the long-term HD patients into average nPCR<1.2 and nPCR≥1.2 groups according to the current guideline. The relation of nPCR with three-year all-cause and cardiovascular (CV) mortality were evaluated. The cox regression method for predicted mortality by nPCR were used. RESULTS OF THE STUDY: Among 88,330 HD patients, 58122 (65.8%) patients were in average nPCR < 1.2 group and 30,208 (34.2%) in average nPCR ≥ 1.2 group. Both all-cause and cardiovascular (CV) mortality risks were increased in nPCR < 1.2 group after adjusting for demographics and laboratories cofactors in our multivariate cox regression model. Patients with nPCR < 1.2 and albumin ≥ 3.7 had a higher adjusted hazard ratio (aHR) for all-cause and CV mortality (1.16 [95% confidence interval (CI): 1.07-1.25, p < 0.001]; 1.15 [95% CI: 1.02-1.31, p=0.03], respectively), compared with the reference group with nPCR ≥ 1.2 and albumin ≥ 3.7. Interestingly, there was no difference in mortality risk between low DPI subgroup (nPCR < 1.2 and Alb < 3.7) and the reference group (nPCR ≥ 1.2 and Alb < 3.7). Further stratification analysis revealed that low DPI subgroup (nPCR < 1.2, Alb ≥ 3.7 and TC ≥ 150) had an increased risk of both all-cause and CV mortality (aHR 1.14 [95% CI: 1.04-1.25, p=0.005]; aHR 1.17 [95% CI: 1.02-1.35, p=0.026], respectively). CONCLUSIONS DRAWN FROM THE STUDY: Low DPI (as presented by nPCR) independently correlated with all-cause and CV mortality among HD patients. Mortality risks were higher in low DPI patients even with normoalbuminemia and non-hypocholesterolemia. Further investigations on the importance of increasing DPI in HD patients is warranted