Effect of initial slow graft function on renal allograft rejection and survival

Cadaver renal allografts with immediate excellent function have good long-term outcomes, while grafts with delayed function have been associated with an increased incidence of acute rejection (AR) and subsequent poor long-term graft survival. There is, however, an intermediate group with initial slow function whose outcome is not well defined. This group was examined by reviewing 510 patients that received primary cadaver transplants between 1/85 and 8/95. Recipients were grouped by initial function into: 1) those with immediate graft function (IGF), defined by serum creatinine (Cr) level < 3 mg/dl on post-operative day (POD) 5 (n = 237); 2) those with slow graft function (SGF), defined by serum Cr > 3 mg/dl on POD 5 but no need for dialysis (n = 160); and 3) those with delayed graft function (DGF), defined by the need for dialysis in the first week post-transplant (n = 113). Five-year graft survivals were determined for each group by Kaplan-Meier methods and compared by a generalized Wilcoxon test. The incidence of AR in the first 6 months was significantly higher in those with SGF (40%) vs. those with IGF (30%) (p < 0.05); both groups had a lower incidence than those with DGF (47%) (p < 0.05). In the absence of AR, 5-yr graft survival was similar between the 3 groups, 94%, 97% and 92% for IGF, SGF and DGF respectively. In the presence of AR, 5-yr graft survival was significantly reduced in all groups, but most notably in those with SGF (51%) or DGF (53%), as compared to those with IGF (80%), (p < 0.001). We conclude that recipients with SGF, but no AR, have excellent outcomes, comparable to those with IGF. However, there is an increased incidence of early AR associated with SGF. In recipients with SGF or DGF, AR has a more profound detrimental effect on long-term graft survival than in the IGF group. Thus, recipients with SGF are at increased risk for AR with resultant poor long-term graft survival, and may need modified immunosuppressive protocols.