Muscle atrophy, inflammation and clinical outcome in incident and prevalent dialysis patients.

Background & Aims: Muscle wasting is considered the best marker of protein-energy wasting in end-stage renal disease (ESRD). We tested the usefulness of a simple observer subjective muscle atrophy (MA) grading in relation to morbidity and mortality in ESRD patients.

Methods: In two different ESRD cohorts (265 incident patients starting dialysis and 221 prevalent hemodialysis patients), each patient's degree of MA was visually graded by a trained nurse on a scale from 1 to 4 as part of the subjective global assessment. This score was confronted with inflammatory and nutritional indexes as well as objective measurements of muscle atrophy. Patients were then prospectively followed for up to four or six years, depending on the cohort.

Results: Thirty percent of the incident and 39% of the prevalent patients presented signs of MA. Across worsening MA scale, nutritional and anthropometric markers of muscle loss were incrementally poorer. Inflammation markers as well as the proportion of women became progressively higher. Female sex, presence of cardiovascular disease, inflammation and low insulin-like growth factor-1 levels were associated with increased significant odd ratios of MA in each cohort. After adjustment for age, sex, inflammation, diabetes, cardiovascular disease, glomerular filtration rate and/or time on hemodialysis, the hazard ratio of death for moderate/severe MA was 2.62 (95% CI: 1.34, 5.13; p=0.001) and 3.04 (95% CI: 1.61, 5.71; p=0.0001) in the incident and prevalent cohorts respectively.

Conclusion: Increased MA is more common in female dialysis patients and associated with inflammation, poor nutritional and anthropometric status, as well as a 3-fold increased 4-6 year mortality. Our data support the use of frequent MA and/or nutritional assessments in the clinical practice.