Purpose: Low serum albumin concentration and low dietary protein intake are associated with protein-energy wasting (PEW) and higher mortality in maintenance hemodialysis patients. The role of these nutritional markers is less clear in clinical outcomes of the first several months of dialysis therapy, where mortality is exceptionally high.
Methods: In a cohort of 17,445 incident hemodialysis patients, we examined variation in serum albumin and the normalized protein catabolic rate (nPCR), a surrogate of dietary intake, and quarterly mortality in the first 2 years of dialysis therapy. Cox proportional hazard models were fitted to estimate the association between mortality and combined albumin/nPCR categories for eight quarters. We investigated the associations between mortality and baseline and subsequent serum albumin levels per cohort quarter as well as changes in albumin and nPCR over time.
Results: Patients were 64 ± 15 years old (mean ± SD) and included 45 % women, 24 % African Americans and 58 % diabetics. Correlations between quarterly serum albumin and nPCR varied from 0.18 to 0.25. Serum albumin <3.5 g/dL was consistently associated with high mortality as was nPCR <1 g/kg/day (except for qtr1). Low serum albumin and nPCR greater than 0.2 g/dLg/dL or g/kg/day, respectively, were associated with increased risk of death. Quarterly rise in nPCR (>+0.2 g/kg/day) showed reverse effect on mortality from the 2nd to the last quarter.
Conclusions: Low serum albumin and nPCR are associated with mortality. A rapid rise in nPCR by the end of the second year may indicate pre-existing PEW.