Prognostic utility of Oxford MEST-C classification for allograft failure in transplant IgA nephropathy: A systematic review and meta-analysis

Background The prognostic value of Oxford MEST-C classification for predicting allograft loss in transplant IgAN remains inconsistent across studies due to transplant-specific challenges. This meta-analysis evaluates the prognostic value of each component of MEST-C as a predictor of allograft failure. Methods A systematic search was performed in PubMed, Embase, Scopus, and the Cochrane Central through March 16, 2026, to identify studies reporting hazard ratios (HRs) for MEST-C scores and graft loss. Univariable and multivariable HRs were pooled using a random-effects model. Potential sources of heterogeneity were identified through sensitivity, subgroup, and meta-regression analyses. Results The study included nine cohorts comprising 1,185 kidney transplant recipients. Pooled analyses showed that S, T, and C lesions were consistently associated with allograft loss, whereas the prognostic value of M and E lesions and the total MEST-C score was less consistent. Subgroup and meta-regression analyses identified geographic region, donor source, and cohort size as significant effect modifiers; however, given the limited number of studies, these associations remain exploratory and hypothesis-generating. Conclusion This meta-analysis of retrospective cohort studies found that S, T, and C lesions were associated with allograft loss after adjustment in heterogeneous, study-specific models, whereas independent associations for M and E were inconsistent. The total MEST-C score showed univariable predictive value; however, limited multivariable pooling failed to confirm an independent association with graft loss. Its clinical utility requires robust prospective validation before routine reporting can be recommended.