Outcome predictability of biomarkers of protein-energy wasting and inflammation in moderate and advanced chronic kidney disease

Background: Markers of protein-energy wasting (PEW) and inflammation are common in chronic kidney disease (CKD) and are among the strongest predictors of mortality in dialysis patients. Objective: We hypothesized that markers of PEWand inflammation show similar associations in patients with non-dialysis-dependent CKD (NDD-CKD). Design: We examined the associations of serum albumin, white blood cell (WBC) count, percentage of lymphocytes in WBCs (%LYM), and a combination of all 3 with all-cause mortality and with the composite of predialysis mortality or end-stage renal disease (ESRD) by using fixed-covariate and time-dependent Cox models in 1220 men with NDD-CKD. Results: Lower albumin and %LYM and a higher WBC count were significantly associated with outcomes. In time-dependent Cox models, compared with patients in whom none of these markers indicated PEW, those in whom 1, 2, or all 3 markers indicated the presence of PEW had multivariable-adjusted hazard ratios (95% CI) for all-cause mortality of 1.7 (1.2, 2.4), 2.4 (1.7, 3.4), and 3.6 (2.5, 5.1); the P for trend was <0.001. Similar associations were present in fixed-covariate models for all-cause mortality and in fixed-covariate and time-dependent models for the composite outcome. Conclusions: Traditional and nontraditional markers of PEW display robust, strong, and independent associations with mortality in patients with NDD-CKD. Clinical trials are warranted to examine whether PEW-improving interventions can lead to better outcomes in these patients.