Faculty Bibliography

Pediatric kidney transplant recipients experience a high-risk age window of increased graft loss during late adolescence and early adulthood that has been attributed primarily to sociobehavioral mechanisms such as nonadherence. An examination of how this age window affects recipients of other organs may inform the extent to which sociobehavioral mechanisms are to blame or whether kidney-specific biologic mechanisms may also exist. Graft loss risk across current recipient age was compared between pediatric kidney (n = 17,446), liver (n = 12,161) and simultaneous liver-kidney (n = 224) transplants using piecewise-constant hazard rate models. Kidney graft loss during late adolescence and early adulthood (ages 17-24 years) was significantly greater than during ages <17 (aHR = 1.79, 95%CI = 1.69-1.90, p < 0.001) and ages >24 (aHR = 1.11, 95%CI = 1.03-1.20, p = 0.005). In contrast, liver graft loss during ages 17-24 was no different than during ages <17 (aHR = 1.03, 95%CI = 0.92-1.16, p = 0.6) or ages >24 (aHR = 1.18, 95%CI = 0.98-1.42, p = 0.1). In simultaneous liver-kidney recipients, a trend towards increased kidney compared to liver graft loss was observed during ages 17-24 years. Late adolescence and early adulthood are less detrimental to pediatric liver grafts compared to kidney grafts, suggesting that sociobehavioral mechanisms alone may be insufficient to create the high-risk age window and that additional biologic mechanisms may also be required.

BACKGROUND:Young women wishing to become living kidney donors frequently ask whether nephrectomy will affect their future pregnancies. METHODS:We conducted a retrospective cohort study of living kidney donors involving 85 women (131 pregnancies after cohort entry) who were matched in a 1:6 ratio with 510 healthy nondonors from the general population (788 pregnancies after cohort entry). Kidney donations occurred between 1992 and 2009 in Ontario, Canada, with follow-up through linked health care databases until March 2013. Donors and nondonors were matched with respect to age, year of cohort entry, residency (urban or rural), income, number of pregnancies before cohort entry, and the time to the first pregnancy after cohort entry. The primary outcome was a hospital diagnosis of gestational hypertension or preeclampsia. Secondary outcomes were each component of the primary outcome examined separately and other maternal and fetal outcomes. RESULTS:Gestational hypertension or preeclampsia was more common among living kidney donors than among nondonors (occurring in 15 of 131 pregnancies [11%] vs. 38 of 788 pregnancies [5%]; odds ratio for donors, 2.4; 95% confidence interval, 1.2 to 5.0; P=0.01). Each component of the primary outcome was also more common among donors (odds ratio, 2.5 for gestational hypertension and 2.4 for preeclampsia). There were no significant differences between donors and nondonors with respect to rates of preterm birth (8% and 7%, respectively) or low birth weight (6% and 4%, respectively). There were no reports of maternal death, stillbirth, or neonatal death among the donors. Most women had uncomplicated pregnancies after donation. CONCLUSIONS:Gestational hypertension or preeclampsia was more likely to be diagnosed in kidney donors than in matched nondonors with similar indicators of baseline health. (Funded by the Canadian Institutes of Health Research and others.).

BACKGROUND: In this study, we present our experience with ureteral complications requiring revision surgery after renal transplantation and compare our results to a matched control population. METHODS: We performed a retrospective analysis of our database between 1997 and 2012. We divided the cases into early (<60 d) and late repairs. Kaplan-Meier and Cox proportional hazards models were used to compare graft survival between the intervention cohort and controls generated from the Scientific Registry of Transplant Recipients data set. RESULTS: Of 2671 kidney transplantations, 51 patients were identified as to having undergone 53 ureteral revision procedures; 43.4% of cases were performed within 60 d of the transplant and were all associated with urinary leaks, and 49% demonstrated ureteral stenosis. Reflux allograft pyelonephritis and ureterolithiasis were each the indication for intervention in 3.8%; 15.1% of the lesions were located at the anastomotic site, 37.7% in the distal segment, 7.5% in the middle segment, 5.7% proximal ureter, and 15.1% had a long segmental stenosis. In 18.9%, the location was not specified. Techniques used included ureterocystostomy (30.2%), ureteroureterostomy (34%), ureteropyelostomy (30.1%), pyeloileostomy (1.9%), and ureteroileostomy (3.8%). No difference in overall graft survival (HR 1.24 95% CI 0.33-4.64, p = 0.7) was detected when compared to the matched control group. CONCLUSION: Using a variety of techniques designed to re-establish effective urinary flow, we have been able to salvage a high percentage of these allografts. When performed by an experienced team, a ureteric complication does not significantly impact graft survival or function as compared to a matched control group.

We have previously described strong associations between frailty, a measure of physiologic reserve initially described and validated in geriatrics, and early hospital readmission as well as delayed graft function. The goal of this study was to estimate its association with postkidney transplantation (post-KT) mortality. Frailty was prospectively measured in 537 KT recipients at the time of transplantation between November 2008 and August 2013. Cox proportional hazards models were adjusted for confounders using a novel approach to substantially improve model efficiency and generalizability in single-center studies. We precisely estimated the confounder coefficients using the large sample size of the Scientific Registry of Transplantation Recipients (n = 37 858) and introduced these into the single-center model, which then estimated the adjusted frailty coefficient. At 5 years, the survivals were 91.5%, 86.0% and 77.5% for nonfrail, intermediately frail and frail KT recipients, respectively. Frailty was independently associated with a 2.17-fold (95% CI: 1.01-4.65, p = 0.047) higher risk of death. In conclusion, regardless of age, frailty is a strong, independent risk factor for post-KT mortality, even after carefully adjusting for many confounders using a novel, efficient statistical approach.

BACKGROUND:The demographic and clinical correlates of gout after living kidney donation are not well described. METHODS:Using a unique database that integrates national registry identifiers of U.S. living kidney donors (1987-2007) with billing claims from a private health insurer (2000-2007), we identified post-donation gout based on medical diagnosis codes or pharmacy fills for gout therapies. The frequencies and demographic correlates of gout after donation were estimated by Cox regression with left- and right-censoring. We also compared the rates of renal diagnoses among donors with and without gout, matched in the ratio 1:3 by age, sex, and race. RESULTS:The study sample of 4,650 donors included 13.1% African Americans. By seven years, African Americans were almost twice as likely to develop gout as Caucasian donors (4.4 vs. 2.4%; adjusted hazard ratio, aHR, 1.8; 95% confidence interval (CI) 1.0-3.2). Post-donation gout risk also increased with older age at donation (aHR per year 1.05) and was higher in men (aHR 2.80). Gout rates were similar in donors and age- and sex-matched general non-donors (rate ratio 0.86; 95% CI 0.66-1.13). Compared to matched donors without gout, donors with gout had more frequent renal diagnoses, reaching significance for acute kidney failure (rate ratio 12.5; 95% CI 1.5-107.0), chronic kidney disease (rate ratio 5.0; 95% CI 2.1-11.7), and other disorders of the kidney (rate ratio 2.2; 95% CI 1.2-4.2). CONCLUSION/CONCLUSIONS:Donor subgroups at increased risk of gout include African Americans, older donors, and men. Donors with gout have a higher burden of renal complications after demographic adjustment.