Assessment of function and survival as measures of renal graft outcome following kidney and kidney-pancreas transplantation in type I diabetics.

Reports on renal graft outcome after kidney-alone (KA) and simultaneous pancreas-kidney (SPK) transplants have focused on graft survival instead of function. The aim of this study is to compare renal graft outcome after KA and SPK using graft function and survival as the measures of outcome. The records of 102 transplants performed in type I diabetics from 10/90 to 9/96 were reviewed (SPK 42, KA 60). Serum creatinine (Cr) and calculated glomerular filtration rate (GFR) were used as estimates of graft function. Cr were similar in SPK and KA on day 3 (4.8 +/- 2.9 vs. 4.8 +/- 2.8 mg/dl, P = 0.9) and day 7 (2.5 +/- 1.8 vs. 3.0 +/- 2.5 mg/dl, P = 0.3). GFR was higher KA at 6 months (57 +/- 18 vs. 51 +/- 12 ml/min, P = 0.08), 1 yr (55 +/- 23 vs. 51 +/- 11 ml/min, P = 0.4) and 3 yr (60 +/- 22 vs. 42 +/- 16 ml/min, P = 0.03). Kidney graft survival was similar in KA and SPK at 1 and 5 yr (87% vs. 89% and 44% vs. 47%, P = 0.8). Immunologic failure of the renal graft occurred more frequently in SPK (58% vs. 48%, P = 0.04) whereas death with function was more common in KA (33% vs. 17%, P = 0.04). In KA, risk factors for failure of the renal graft included acute rejection (P = 0.008, relative risk or rr = 3.4) and African American recipient (P = 0.06, rr = 2.8). In SPK, risk factors included donor age > 40 yr (P = 0.05, rr = 5.3) and African American donor (P = 0.03, rr = 4.5). Logistic regression analysis revealed the following risk factors for GFR < 50 ml/min at 1 yr: acute rejection (P = 0.03, rr = 2.2) and Cr > 3 mg/dl on day 7 (P = 0.06, rr = 2.3). In conclusion, although renal graft survival was similar after KA and SPK, better graft function was observed in KA at 3 yr. Assessment of renal graft function allows us to evaluate outcome from a different perspective than graft survival, and these two measures of outcome complement each other.