Faculty Bibliography

BACKGROUND: Patient-level risk factors for delayed graft function (DGF) have been well described. However, the Organ Procurement and Transplantation Network definition of DGF is based on dialysis in the first week, which is subject to center-level practice patterns. It remains unclear if there are center-level differences in DGF and if measurable center characteristics can explain these differences. METHODS: Using the 2003 to 2012 Scientific Registry of Transplant Recipients data, we developed a hierarchical (multilevel) model to determine the association between center characteristics and DGF incidence after adjusting for known patient risk factors and to quantify residual variability across centers after adjustment for these factors. RESULTS: Of 82,143 deceased donor kidney transplant recipients, 27.0% developed DGF, with a range across centers of 3.2% to 63.3%. A center's proportion of preemptive transplants (odds ratio [OR], 0.83; per 5% increment; 95% confidence interval [95% CI], 0.74-;0.93; P = 0.001) and kidneys with longer than 30 hr of cold ischemia time (CIT) (OR, 0.95; per 5% increment; 95% CI, 0.92-;0.98; P = 0.001) were associated with less DGF. A center's proportion of donation after cardiac death donors (OR, 1.12; per 5% increment; 95% CI, 1.03-;1.17; P < 0.001) and imported kidneys (OR, 1.06; per 5% increment; 95% CI, 1.03-;1.10; P < 0.001) were associated with more DGF. After patient-level and center-level adjustments, only 41.8% of centers had DGF incidences consistent with the national median and 28.2% had incidences above the national median. CONCLUSION: Significant heterogeneity in DGF incidences across centers, even after adjusting for patient-level and center-level characteristics, calls into question the generalizability and validity of the current DGF definition. Enhanced understanding of center-level variability and improving the definition of DGF accordingly may improve DGF's utility in clinical care and as a surrogate endpoint in clinical trials.

BACKGROUND:Mycophenolate mofetil (MMF) side effects often prompt dose reduction or discontinuation, and this MMF dose reduction (MDR) can lead to rejection and possibly graft loss. Unfortunately, little is known about what factors might cause or contribute to MDR. Frailty, a measure of physiologic reserve, is emerging as an important, novel domain of risk in kidney transplantation recipients. We hypothesized that frailty, an inflammatory phenotype, might be associated with MDR. METHODS:We measured frailty (shrinking, weakness, exhaustion, low physical activity, and slowed walking speed), other patient and donor characteristics, longitudinal MMF doses, and graft loss in 525 kidney transplantation recipients. Time-to-MDR was quantified using an adjusted Cox proportional hazards model. RESULTS:By 2 years after transplantation, 54% of frail recipients and 45% of nonfrail recipients experienced MDR; by 4 years, incidence was 67% and 51%. Frail recipients were 1.29 times (95% confidence interval [95% CI], 1.01-1.66; P = 0.04) more likely to experience MDR, as were deceased donor recipients (adjusted hazard ratio [aHR], 1.92; 95% CI, 1.44-2.54, P < 0.001) and older adults (age ≥ 65 vs <65; aHR, 1.47; 95% CI, 1.10-1.96, P = 0.01). Mycophenolate mofetil dose reduction was independently associated with a substantially increased risk of death-censored graft loss (aHR, 5.24; 95% CI, 1.97-13.98, P = 0.001). CONCLUSION/CONCLUSIONS:A better understanding of risk factors for MMF intolerance might help in planning alternate strategies to maintain adequate immunosuppression and prolong allograft survival.