Health & Medical Organ Transplants & Donation

Risk Factors for Retransplant Kidney Recipients

Risk Factors for Retransplant Kidney Recipients

Abstract and Introduction

Abstract


As of November 2013, 14.5% of the waitlist for a donor kidney comprised patients awaiting a retransplant. We performed a retrospective cohort study of 11 698 adult solitary kidney recipients using national Scientific Registry of Transplant Recipients data transplanted between 2002 and 2011. The aim was to investigate whether outcomes from patients' initial transplants are significant risk factors for patients' repeat transplants or for likelihood of relisting after a failed primary transplant. Retransplant recipients were more likely to be treated for acute rejection [adjusted odds ratio (AOR), 95% confidence interval (CI) = 1.26 (1.07–1.48), p = 0.0053] or hospitalized (AOR = 1.19, 95% CI 1.08–1.31, p = 0.0005) within a year of retransplantation if these outcomes were experienced within a year of primary transplant. Delayed graft function following primary transplants was associated with 35% increased likelihood of recurrence (AOR = 1.35, 95% CI = 1.18–1.54, p < 0.0001). An increase in 1-year GFR after primary transplant was associated with GFR 1 year postretransplant (β = 6.82, p < 0.0001), and retransplant graft failure was inversely associated with 1-year primary transplant GFR (adjusted hazard ratio = 0.74, 95% CI = 0.71–0.76 per 10 mL/min/1.73 m). A decreased likelihood for relisting was associated with hospitalization and higher GFR following primary transplantation. The increasing numbers of individuals requiring retransplants highlights the importance of incorporating prior transplant outcomes data to better inform relisting decisions and prognosticating retransplant outcomes.

Introduction


As of November 15, 2013, 14.5% of the waitlist for a deceased donor kidney comprised patients awaiting a kidney retransplant. In 2011, 11.8% of recipients of kidney transplants were retransplants in the United States. In the decade prior to 2007, the number of kidney retransplants increased by 40% due to a greater number of renal transplants performed and to a greater number of patients suffering from allograft loss. This trend will likely continue to rise given the increased use of marginal donor organs and higher-risk recipients receiving transplantation. Research has shown that graft survival and rejection rates in retransplantation are generally inferior to primary transplantation.

Overall, retransplant recipients have a higher panel reactive antibody (PRA) level at listing compared to primary recipients, which accounts for part of the high-risk nature of regraft kidney recipients and the decreased likelihood to receive a donor transplant rapidly. More than half of the cases of primary graft failure that occur in the first year are attributed to acute rejection and graft thrombosis. If the primary loss occurs more than a year after transplantation, one study suggests that chronic rejection accounts for almost two-thirds of graft losses. The unadjusted 1-, 3-, and 5-year graft survival rates for both repeat living and deceased donor transplants are significantly lower than the survival rates for primary transplants. The adjusted relative risk of graft failure following repeat kidney transplantation after 3 years is also significantly worse than primary transplants.

Despite the increased relative risks associated with retransplantation, patients receive a significant survival benefit as opposed to remaining on dialysis after a failed transplant. Several studies have shown that survival of a first graft is an important determinant of subsequent transplant outcome Risk factors including previous graft survival, graft loss because of rejection and time to retransplant are significantly associated with regraft survival. In addition, patients who lose their first allograft within 36 months posttransplant are at increased risk for second allograft loss compared to patients with an initial allograft lasting more than 36 months. For patients with a first transplant surviving longer than 3 years, the relative risk of repeat transplant failure declined in a linear fashion, indicating that the timing of first graft loss should be considered in the approach taken to repeat transplantation.

Data have shown that outcomes from patients' initial transplant may inform patients' viability and risk for outcomes during repeat transplants. The aim of this study was to investigate which outcomes from patients' initial transplant would be significant independent risk factors for repeat transplant outcomes using a large sample of national data including living and deceased donor kidney recipients. Based on initial findings, we subsequently aimed to determine whether the likelihood of relisting patients for a retransplant is associated with primary transplant outcomes. Graft survival and relevant clinical end points following retransplantation were comprehensively investigated. The primary hypothesis was that patients' outcomes from their initial transplants would have a significant association with repeat transplant outcomes and that initial transplant outcomes may have an impact on whether or not patients are relisted for a retransplant.

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