Faculty Bibliography

BACKGROUND: Recent evidence suggests that living kidney donors are at an increased risk of end-stage renal disease. However, predicting which donors will have renal dysfunction remains challenging, particularly among those with no clinical evidence of disease at the time of donation. Although renal biopsies are not routinely performed as part of the donor evaluation process, they may yield valuable information that improves the ability to predict renal function in donors. METHODS: We used implantation protocol biopsies to evaluate the association between histological abnormalities in the donated kidney and postdonation renal function (estimated glomerular filtration rate, eGFR) of the remaining kidney in living kidney donors. Longitudinal analysis using mixed-effects linear regression was used to account for multiple eGFR measures per donor. RESULTS: Among 310 donors between 1997 and 2012, median (IQR) follow-up was 6.2 (2.5-8.7; maximum 14.0) years. In this cohort, the overall prevalence of histological abnormalities was 65.8% (19.7% abnormal glomerulosclerosis, 23.9% abnormal interstitial fibrosis and tubular atrophy (IFTA), 4.8% abnormal mesangial matrix increase, 32.0% abnormal arteriolar hyalinosis, and 32.9% abnormal vascular intimal thickening). IFTA was associated with a 5-mL/min/1.73 m decrease of postdonation eGFR after adjusting for donor age at donation, sex, race, preoperative systolic blood pressure, preoperative eGFR, and time since donation (P < 0.01). CONCLUSIONS: In this single-center study, among healthy individuals cleared for living donation, IFTA was associated with decreased postdonation eGFR, whereas no other subclinical histological abnormalities provided additional information.

The infrequent use of ABO-incompatible (ABOi) kidney transplantation in the United States may reflect concern about the costs of necessary preconditioning and posttransplant care. Medicare data for 26 500 live donor kidney transplant recipients (2000 to March 2011), including 271 ABOi and 62 A2-incompatible (A2i) recipients, were analyzed to assess the impact of pretransplant, transplant episode and 3-year posttransplant costs. The marginal costs of ABOi and A2i versus ABO-compatible (ABOc) transplants were quantified by multivariate linear regression including adjustment for recipient, donor and transplant factors. Compared with ABOc transplantation, patient survival (93.2% vs. 88.15%, p = 0.0009) and death-censored graft survival (85.4% vs. 76.1%, p < 0.05) at 3 years were lower after ABOi transplant. The average overall cost of the transplant episode was significantly higher for ABOi ($65 080) compared with A2i ($36 752) and ABOc ($32 039) transplantation (p < 0.001), excluding organ acquisition. ABOi transplant was associated with high adjusted posttransplant spending (marginal costs compared to ABOc - year 1: $25 044; year 2: $10 496; year 3: $7307; p < 0.01). ABOi transplantation provides a clinically effective method to expand access to transplantation. Although more expensive, the modest increases in total spending are easily justified by avoiding long-term dialysis and its associated morbidity and cost.

BACKGROUND: A report from a high-volume single center indicated a survival benefit of receiving a kidney transplant from an HLA-incompatible live donor as compared with remaining on the waiting list, whether or not a kidney from a deceased donor was received. The generalizability of that finding is unclear. METHODS: In a 22-center study, we estimated the survival benefit for 1025 recipients of kidney transplants from HLA-incompatible live donors who were matched with controls who remained on the waiting list or received a transplant from a deceased donor (waiting-list-or-transplant control group) and controls who remained on the waiting list but did not receive a transplant (waiting-list-only control group). We analyzed the data with and without patients from the highest-volume center in the study. RESULTS: Recipients of kidney transplants from incompatible live donors had a higher survival rate than either control group at 1 year (95.0%, vs. 94.0% for the waiting-list-or-transplant control group and 89.6% for the waiting-list-only control group), 3 years (91.7% vs. 83.6% and 72.7%, respectively), 5 years (86.0% vs. 74.4% and 59.2%), and 8 years (76.5% vs. 62.9% and 43.9%) (P<0.001 for all comparisons with the two control groups). The survival benefit was significant at 8 years across all levels of donor-specific antibody: 89.2% for recipients of kidney transplants from incompatible live donors who had a positive Luminex assay for anti-HLA antibody but a negative flow-cytometric cross-match versus 65.0% for the waiting-list-or-transplant control group and 47.1% for the waiting-list-only control group; 76.3% for recipients with a positive flow-cytometric cross-match but a negative cytotoxic cross-match versus 63.3% and 43.0% in the two control groups, respectively; and 71.0% for recipients with a positive cytotoxic cross-match versus 61.5% and 43.7%, respectively. The findings did not change when patients from the highest-volume center were excluded. CONCLUSIONS: This multicenter study validated single-center evidence that patients who received kidney transplants from HLA-incompatible live donors had a substantial survival benefit as compared with patients who did not undergo transplantation and those who waited for transplants from deceased donors. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.).

The updated Banff classification allows for the diagnosis of antibody-mediated rejection (AMR) in the absence of peritubular capillary C4d staining. Our objective was to quantify allograft loss risk in patients with consistently C4d-negative AMR (n = 51) compared with C4d-positive AMR patients (n = 156) and matched control subjects without AMR. All first-year posttransplant biopsy results from January 2004 through June 2014 were reviewed and correlated with the presence of donor-specific antibody (DSA). C4d-negative AMR patients were not different from C4d-positive AMR patients on any baseline characteristics, including immunologic risk factors (panel reactive antibody, prior transplant, HLA mismatch, donor type, DSA class, and anti-HLA/ABO-incompatibility). C4d-positive AMR patients were significantly more likely to have a clinical presentation (85.3% vs. 54.9%, p < 0.001), and those patients presented substantially earlier posttransplantation (median 14 [interquartile range 8-32] days vs. 46 [interquartile range 20-191], p < 0.001) and were three times more common (7.8% vs 2.5%). One- and 2-year post-AMR-defining biopsy graft survival in C4d-negative AMR patients was 93.4% and 90.2% versus 86.8% and 82.6% in C4d-positive AMR patients, respectively (p = 0.4). C4d-negative AMR was associated with a 2.56-fold (95% confidence interval, 1.08-6.05, p = 0.033) increased risk of graft loss compared with AMR-free matched controls. No clinical characteristics were identified that reliably distinguished C4d-negative from C4d-positive AMR. However, both phenotypes are associated with increased graft loss and thus warrant consideration for intervention.

The Open Payments Program (OPP) was recently implemented to publicly disclose industry payments to physicians, with the goal of enabling patient awareness of potential conflicts of interests. Awareness of OPP, its data, and its implications for transplantation are critical. We used the first wave of OPP data to describe industry payments made to transplant surgeons. Transplant surgeons (N = 297) received a total of $759 654. The median (interquartile range [IQR]) payment to a transplant surgeon was $125 ($39-1018), and the highest payment to an individual surgeon was $83 520; 122 surgeons received <$100, and 17 received >$10 000. A higher h-index was associated with 30% higher chance of receiving >$1000 (relative risk/10 unit h-index increase = 1.18 1.301.44 , p < 0.001). The highest payment category was consulting fees, with a total of $314 448 paid in this reported category. Recipients of consulting fees had higher h-indices, median (IQR) of 20 (10-35) versus nine (3-17) (p < 0.001). Ten of 122 companies accounted for 62% of all payments. Kidney transplant and liver transplant (LT) centers that received >$1000 had higher center volumes (p < 0.001). LT centers that received payments of >$1000 had a higher percentage of private-insurance/self-pay patients (p < 0.01). Continued surveillance of industry payments may further elucidate the relationship between industry payments and physician practices.