Background

Protein-energy wasting (PEW) is a common condition in patients with chronic kidney disease (CKD) including dialysis and kidney transplant recipients (TX) and frequently assessed with malnutrition-inflammation score (MIS). We hypothesized that (1) the MIS and PEW parameters are correlated with kidney function and (2) the MIS and PEW parameters are more severe in TX than in non-dialysis (ND) CKD patients with similar eGFR.

Methods

In this study, we matched 203 ND-CKD and 203 TX patients from two independently assembled cohorts of patients based on estimated glomerular filtration rate (eGFR) and compared various PEW parameters between the two groups using unadjusted and case-mix adjusted linear regression and conditional logistic regression analysis models.

Results

In the combined cohort (n = 406) of patients, the mean ± SD age was 57 ± 12 years; included 55 % men and 35 % diabetics; and demonstrated a mean ± SD baseline eGFR of 29 ± 11 ml/min/1.73 m(2). The eGFR correlated positively with serum albumin (ρ = 0.26, p < 0.001) and negatively (ρ = -0.33, p < 0.001) with MIS. ND-CKD and TX patients had similar MIS, PEW parameters such as waist circumference, serum CRP, albumin, and leptin levels. After case-mix adjustment, TX status was associated with higher waist circumference (standardized coefficient: 0.187, p < 0.001), lower BMI (standardized coefficient: -0.204, p < 0.001), and lower SGA score (standardized coefficient: 0.156, p = 0.006).

Conclusions

We found associations between lower eGFR and various PEW measures in both the ND-CKD and TX populations. Additionally, we did not observe significant differences in the burden of PEW parameters between the CKD and TX populations.

Objective

To better define the prevalence of protein-energy wasting (PEW) in kidney disease is poorly defined.

Methods

We performed a meta-analysis of PEW prevalence from contemporary studies including more than 50 subjects with kidney disease, published during 2000-2014 and reporting on PEW prevalence by subjective global assessment or malnutrition-inflammation score. Data were reviewed throughout different strata: (1) acute kidney injury (AKI), (2) pediatric chronic kidney disease (CKD), (3) nondialyzed CKD 3-5, (4) maintenance dialysis, and (5) subjects undergoing kidney transplantation (Tx). Sample size, period of publication, reporting quality, methods, dialysis technique, country, geographical region, and gross national income were a priori considered factors influencing between-study variability.

Results

Two studies including 189 AKI patients reported a PEW prevalence of 60% and 82%. Five studies including 1776 patients with CKD stages 3-5 reported PEW prevalence ranging from 11% to 54%. Finally, 90 studies from 34 countries including 16,434 patients on maintenance dialysis were identified. The 25th-75th percentiles range in PEW prevalence among dialysis studies was 28-54%. Large variation in PEW prevalence across studies remained even when accounting for moderators. Mixed-effects meta-regression identified geographical region as the only significant moderator explaining 23% of the observed data heterogeneity. Finally, two studies including 1067 Tx patients reported a PEW prevalence of 28% and 52%, and no studies recruiting pediatric CKD patients were identified.

Conclusion

By providing evidence-based ranges of PEW prevalence, we conclude that PEW is a common phenomenon across the spectrum of AKI and CKD. This, together with the well-documented impact of PEW on patient outcomes, justifies the need for increased medical attention.