Risk factors for IgA nephropathy recurrence and impact on graft survival in a cohort of kidney transplanted patients

Recurrence of IgA nephropathy (IgAN) after kidney transplant (KT) appears associated with worse graft survival; thus, the identification of risk factors is worthwhile to improve pre-transplant evaluation of KT recipients and to identify the optimal treatment strategy. The aim of this study was to determine incidence, risk factors and impact on renal function and graft survival of IgAN recurrence after KT. We performed a retrospective study including 110 patients with biopsy-proven IgAN, who underwent KT at Policlinico di Sant'Orsola Hospital - University of Bologna from 2005 to 2021. IgAN recurred in 14 patients (12.7%) with a median time-to-recurrence of 59 (16-90) months. We found that a faster progression from IgAN diagnosis to end-stage kidney disease (ESKD), a younger age at ESKD, and a younger age at KT were associated with a higher risk of recurrence. During the first 2 years after KT, 24 h proteinuria was higher in patients with IgAN recurrence than in patients without (0.40 (0.11-1.8) vs 0.22 (0.18-0.37) g/day, <i>p</i> = 0.0003). During the follow-up period, a more rapid decline in eGFR was observed in the Recurrence group (<i>p</i> = 0.023). Additionally, graft survival at 10 years post-kidney transplant was significantly lower in this group (log-rank test <i>p</i> = 0.015). In conclusion, we found that patients with a more aggressive form of IgAN, who reached ESKD before 36 years of age, had an higher risk of recurrence in KT. Moreover we confirmed that recurrent IgAN, especially if clinically relevant, is associated with a worse graft outcome.