Body mass index as a predictive factor for long-term renal transplant outcomes in Asians

Background: There is substantial evidence that renal transplant recipients with obesity or body mass index > 30 kg/m(2) have increased risk of graft loss. However, few data exist for Asian population; clinicians have to rely upon indirect evidence by extrapolating the results from Caucasians to Asian recipients. Study: Using data from a study population of 150 consecutive cadaveric or living related Chinese renal transplant recipients at our center between 1985 and 2002, we examined the effect of baseline body mass index cut-off 25 kg/m(2) on the transplant outcomes using Kaplan-Meier analysis and Cox proportional hazards analysis. Primary study end point was overall graft survival. Results: The mean body mass index was 22.9 +/- 4.0 kg/m(2). Thirty-seven (25%) patients were classified as overweight and 113 patients as non-overweight, using the cut-off of 25 kg/m(2). After median follow up period of nine yr, 15 graft losses (41%) occurred in the overweight group, as compared with 14 graft losses (12%) in the non-overweight group. Kaplan-Meier estimates of cumulative graft survival at five yr were significantly worse for the overweight group than non-overweight group (83.6% versus 92.7%, p = 0.0041). By multivariate Cox proportional hazards analysis, baseline body mass index >= 25 kg/m(2) conferred a significantly higher risk of graft loss (with relative risk of 4.78, 95% CI = 1.52-15.2) and doubling of serum creatinine (relative risk 3.19, 95% CI = 1.22-8.40). Death with a functioning graft occurred in 11% of overweight recipients, compared with 3% among the non-overweight group (p = 0.041). Conclusion: Our results draw attention to a recipient body mass index cut-off value >= 25 kg/m(2), which might confer an increased risk of graft loss in Asian kidney transplant populations.