The aim is to evaluate the effect of donor kidney mass and recipient body mass index (BMI), on short and long-term graft survival. During 1989–2000, 600 renal transplants have been performed in our center. One hundred and fifteen of them were studied and followed for an average of 5 years. Weight of grafted kidneys (donor kidney mass), and recipients’ BMI were measured at the time of operation in all cases. Nephron Mass Index (NMI) was defined as the ratio of donor kidney mass to recipient BMI, and this ratio was calculated for all 115 cases. During the follow up period, serum creatinine was measured. Also, acute and chronic rejection episodes were identified. The mean NMI was 8 and mean creatinine level was 1.45 mg/dL. There were 20 cases of acute rejection, which managed successfully with antithymocyte globulin (ATG) in 17 cases. Three patients lost their graft. There were four cases of graft loss due to chronic rejection. Using Pearson correlation, we found no association between NMI and mean serum creatinine level. Logistic regression showed significant relation between NMI and acute rejection (P <0.05), with odds ratio of .2. There was no significant correlation between NMI and chronic rejection.
The incidence of acute rejection is higher when there is less donor nephron mass for greater recipient body mass (smaller NMI). However, in long term, there is no significant correlation between graft survival and NMI. Also, mean creatinine level is not significantly different in patients regardless of their NMI.