Analysis of Clinical Outcomes According to the Definition of Slow Graft Function in Deceased Donor Kidney Transplantation

Background: Slow graft function (SGF) is considered to be an intermediate state between immediate graft function (IGF) and delayed graft function (DGF). However, the criteria of SGF is still arbitrary, and the clinical outcomes of SGF are not fully understood. Methods: A total of 212 deceased donor kidney transplantation recipients were enrolled. Three schemas were adopted, which classified SGF according to the serum creatinine (Cr) level by a given postoperative day (POD). SGF was defined as Cr ≥ 3.0 mg/dL on POD5, Cr ≥ 2.5 mg/dL on POD7, and Cr ≥ 1.5 mg/dL on POD14 without dialysis in schema I, II, and III, respectively. Estimated glomerular filtration rate (eGFR) after transplantation, acute rejection, and graft survival were compared in each schema. Decreased renal function, defined as eGFR less than 30.0 mL/min/1.73m², was also compared. Results: In schema I and III, SGF had significantly lower eGFR at 3 months after transplantation compared with IGF (P <.017), and only schema III maintained the difference until 36 months after transplantation. The incidence of decreased renal function showed significant difference among groups in schema I and III (P <.05). Graft survival did not show significant difference among groups in all schemas. However, SGF and DGF groups showed a higher probability of decreased renal function than the IGF group (P <.017) in schema I and III. Conclusions: In deceased donor kidney transplantation, certain definitions of SGF identified significantly worse clinical outcomes compared with IGF, suggesting similar impact with DGF. It is necessary to reach a consensus on a clearer definition of SGF with further studies.