Protein energy wasting and long-term outcomes in nondialysis dependent chronic kidney disease

Background: Nutritional status and protein energy wasting (PEW) is prevalent in patients with nondialysis-dependent chronic kidney disease (CKD). The relationship between PEW and long-term development of clinically important outcomes remains to be examined. Objectives: To investigate the relationships between PEW, as measured by Subjective Global Assessment (SGA 1-7), and progression to important clinical outcomes: mortality and/or kidney failure. Design: Prospective cohort design. Participants: One hundred and thirty-nine participants were well-nourished and 37 moderately malnourished patients with CKD 3-5. Measurements: The outcomes were 2, 5, and 10-year progression to kidney failure (dialysis or transplant) or mortality, kidney failure alone, and mortality alone. SGA was determined by a registered renal dietitian. Food frequency questionnaires were used to assess dietary intake. Clinical and laboratory baseline characteristics were collected. Multivariable regression models and Cox models were created to examine the relationship between SGA and outcomes. Results: PEW was associated with the combined outcome of kidney failure or mortality at 2 (p = 0.003), 5 (p = 0.004), but not at 10 (p = 0.73) years. This relationship was primarily driven by the relationship between PEW and kidney failure. In Cox models, the relationship between PEW and kidney failure remained after adjusting for Kidney Failure Risk Equation scores. The multivariable modeling revealed that PEW remained a statistically significant predictor of the combined outcome and ESKD after adjustment for age, estimated glomerular filtration rate (eGFR), sex, albumin-to-creatinine ratio, diabetes, albumin, and protein intake. Conclusions: PEW, determined by the SGA 1-7, is an important prognostic tool. Further research looking at clinically important outcomes are needed to implement nutritional interventions for nondialysis-dependent CKD patients.