[The effect of obesity on outcome of kidney transplantation]

Obesity is a risk factor for postoperative complications in surgery. In a retrospective study we investigated the course of body weight during the waiting period and the first postoperative year and the influence of obesity on graft function.

The medical records of 334 adult patients undergoing cadaveric kidney transplantation between 1986 and 1992 were reviewed. Immunosuppression was performed with cyclosporine and prednisone. For all patients the Broca index was calculated with the relative body weight by the formula: body weight/Broca index x 100 (% BI). Obesity was defined as relative body weight > or = 120% BI.

At the time of the indication for kidney transplantation 15.3% of the patients were obese. Only 12 of these 51 obese patients reduced their body weight below 120% BI until transplantation, whereas 25 patients increased weight in excess of 120% BI. Thus the number of obese patients raised to 19.2% by the time of transplantation. The graft survival in the obese group was significantly lower than in the nonobese group. This difference appeared already in the first half year after transplantation being constant in the following time. The resulting 1-year graft survival was 82.8% and 91.4% respectively (p < 0.05). During the first year 59 patients more became obese, the percentage of obese raised up to 36.0%. One year after transplantation there was no longer significant difference of graft survival rate in the further follow-up between obese and nonobese patients.

Our findings show, that obesity is an important risk factor for early graft loss. Therefore all participating physicians assume a great responsibility for the pre-operative treatment during the waiting time.