Determinants of short-term changes in body composition following renal transplantation.

Objective: Changes in body composition after renal transplantation (RTx) are of clinical significance, since increments in fat mass may contribute to glucose intolerance and cardiovascular morbidity. The aim of this study was to quantify the early changes in body composition after transplantation and identify predictors of these changes.

Material And Methods: Total and regional body composition of 102 first kidney allograft recipients were measured at transplantation and after 10 weeks using dual-energy X-ray absorptiometry. The population comprised a high proportion of pre-emptive and well-nourished kidney recipients. Multiple linear regression was used to identify predictors of change.

Results: Mean fat mass was 27.1+/-8.7% of body weight at baseline. The fat mass percentage increased by 2.2% corresponding to a 1.3 kg increase in fat mass at 10 weeks (p< 0.001). Fat-free mass declined by 2.5 kg (p<0.001), with no significant loss of body weight (0.9 kg, p=0.11). Age, low-tertile fat mass, plasma C-reactive protein, time on dialysis and cumulative prednisolone dose were independent predictors (p<0.05) of the increase in fat mass. Cumulative prednisolone dose was the only significant predictor of decrease in fat-free mass. Essentially the same results were found for both genders.

Conclusions: A significant increase in fat mass occurred rapidly after RTx along with a reduction in fat-free mass despite stable body weight. Early fat mass accumulation may predispose to comorbidity, but the long-term clinical significance of these early changes remains to be explored in prospective studies.