Renal graft survival according to Banff 2013 classification in indication biopsies. / Supervivencia del injerto renal según la categoría de Banff 2013 en biopsia por indicación.

ABSTRACT

INTRODUCTION: The impact of acute rejection in kidney graft survival is well known, but the prognosis of other diagnoses is uncertain. We evaluated the frequency and impact on graft survival of different diagnostic categories according to the Banff 2013 classification in a cohort of renal transplant recipients. MATERIAL AND METHODS: Retrospective study of 495 renal biopsies by indication in 322 patients from 1990-2014. Two independent observers reviewed the histological reports, reclassifying according to the Banff 2013 classification. RESULTS: Of 495 biopsies, 28 (5.7%) were not diagnostic. Of the remaining 467, 10.3% were «normal¼ (category 1), 19.6% antibody-mediated changes (category 2), 5.9% «borderline¼ changes (category 3), 8.7% T-cell-mediated rejection (category 4), 23.4% interstitial fibrosis/tubular atrophy (IFTA) (category 5) and 26.5% with other diagnoses (category 6). As time after transplantation increases, diagnoses of categories 1, 3 and 4 decrease, while categories 5 and 2 increase. Worse graft survival with category 2 diagnosis was observed (45% at 7.5 years, HR 4.29 graft loss [95% CI, 2.39-7.73]; P≤.001, compared to category 1). Grafts with «unfavourable histology¼ (chronic antibody-mediated rejection, moderate-severe IFTA) presented worse survival that grafts with «favourable histology¼ (normal, acute tubular necrosis, mild IFTA). CONCLUSIONS: The Banff 2013 classification facilitates a histological diagnosis in 95% of indication biopsies. While diagnostic category 6 is the most common, a change in the predominant histopathology was observed according to time elapsed since transplantation. Antibody-mediated changes are associated with worse graft survival.