Influence of body composition on 5 year mortality in patients on regular haemodialysis

Background. Reduction of body mass index (BMI) significantly affects mortality in haemodialysis (HD) patients, but it remains to be determined which of the body components influences mortality. Methods. We examined the whole body composition of 262 HD patients by dual-energy X-ray absorptiometry (DEXA) (age: 60 +/- 12 years; HD duration 9+/-7 years; male/female: 177/85; diabetics, n=50) and subsequently followed mortality for 5 years. Results. Patient age was significantly correlated with limb/trunk lean mass (LTLM) ratio (r=-0.350, P< 0.01) and % fat content in whole tissue (r=0.145, P=0.02). There was a significant positive relationship between LTLM ratio and serum creatinine both in males (r=0.404, P<0.01) and females (r=0.267, P= 0.01). Diabetic males and females both had a significantly lower LTLM ratio than non-diabetic males (P<0.01) and females (P<0.04). During the 5 years, 65 patients (24.8%) died mainly of cardiovascular diseases and infections. BMI was lower in the expired group than in survivors (P<0.04). LTLM ratio was significantly reduced in the expired group compared with the surviving males (0.629 +/- 0.097 vs 0.707 +/- 0.094; P < 0.01) and females (0.611 +/- 0.101 vs 0.651 +/- 0.078; P<0.01). Cox's proportional hazards analysis revealed that the reduction of LTLM ratio was a significant determinant of death in men (P<0.01), while a lower percentage of fat content of trunk was a significant determinant of death in women (P < 0.01). In contrast, BMI did not influence mortality in either sex. Conclusions. Measurements of regional lean and fat mass volumes by DEXA may be useful for predicting death in patients receiving long-term HD.