Factors associated with peak oxygen uptake in hemodialysis patients awaiting renal transplantation

The preoperative evaluation of pulmonary function is important in renal transplantation candidates. Exercise capacity determined by peak oxygen uptake (peak Vo(2)) is a predictor of perioperative mortality and survival. The aim of this study was to determine the factors associated with the peak Vo(2) among renal transplantation candidates undergoing hemodialysis. Thirty patients with chronic renal failure including 14 women and 16 men of mean age 40.2 +/- 10.3 years had a mean duration of dialysis of 133.1 +/- 63.3 months and were awaiting renal transplantation. None of the patients had signs or symptoms of active infection or inflammation. Each patient underwent pulmonary function and symptom-limited cardiopulmonary exercise tests. Despite the absence of clinically evident inflammation, a malnutrition inflammation score was calculated for each patient to assess comorbid conditions and the risk of atherosclerosis. Demographic and laboratory parameters were obtained from hospital records. The peak Vo(2) was positively correlated with the serum triglyceride level and negatively correlated with serum ferritin level and malnutrition inflammation score. On multiple linear regression analyses, which were performed to assess the potential predictors of the peak Vo(2), the malnutrition inflammation score was the only variable that independently correlated with the peak Vo(2) in hemodialysis patients awaiting renal transplantation. In conclusion, peak Vo(2) is associated with markers of nutrition and the malnutrition inflammation score. We suggest that chronic malnutrition and silent inflammation may be responsible for the preoperative decreased exercise capacity in renal transplantation candidates undergoing hemodialysis.