A comparative analysis of nutritional parameters as predictors of outcome in male and female ESRD patients

BACKGROUND: Many patients with end-stage renal disease (ESRD) are malnourished and cross-sectional studies show that markers of malnutrition may predict death. Serum albumin (S-albumin), the commonest nutritional marker, has been criticized because it is so closely related to the effects of inflammation and other non-nutritional factors. Consequently, we need other nutritional markers that can predict outcome. However, males and females differ as regards body composition and it is not known how this may influence the predictive power of different nutritional markers. METHODS: In 206 ESRD patients (126 males) aged 52+/-1 years, we evaluated the relationship between survival and five estimates of nutritional status (S-albumin, subjective global assessment (SGA), lean body mass (LBM), body fat mass (FM) assessed by dual-energy X-ray absorptiometry, and handgrip strength (HGS)) close to start of renal replacement therapy (RRT). The patients were also classified as regards the presence of cardiovascular disease (CVD), diabetes mellitus (DM), and inflammation (CRP> or = 10 mg/l). Mortality was monitored over mean follow-up period of 37+/-2 months. RESULTS: In the whole patient group, the presence of CVD, DM, inflammation, and malnutrition (SGA >1) close to start of RRT all predicted poor outcome. However, whereas inflammation strongly predicted (P<0.0001) poor outcome in males, no such effect was observed in females. Also, differences were found between males and females regarding the predictive value of the five different nutritional estimates. Whereas HGS, SGA, and S-albumin independently predicted poor outcome in males, only SGA predicted outcome (independently of age, CVD, and DM) in females. CONCLUSIONS: Mild to moderate malnutrition, as assessed by SGA, was present in 39% of the patients and predicted outcome independently of age and co-morbidity in both males and females. However, the predictive power of various other nutritional markers differed markedly between male and female patients. Whereas a low HGS was an excellent independent outcome predictor in males, no predictive power of this parameter was found in females. S-albumin is more closely related to co-morbidity and inflammation than nutritional status in patients close to start of RRT. We conclude that sex is an important factor that must be taken into account in studies on nutrition and nutritional interventions in ESRD patients.