Clinical usefulness of the Oxford classification in determining immunosuppressive treatment in IgA nephropathy

Background: The Oxford classification has been widely used in IgA nephropathy. However, its clinical usefulness of determining immunosuppression is unknown.

Aim: Whether the Oxford classification could predict the development of proteinuria ≥1?g/g Cr and worsening kidney function, as well as the clinical efficacy of corticosteroid treatment according to each histologic variable of the Oxford-MEST.

Methods: We included 377 patients with early-stage IgA nephropathy. The study endpoints were the development of a heavy proteinuria and a decline renal function.

Results: The results showed that among the Oxford-MEST lesions, only M1 predicted the risk of the development of proteinuria ≥1.0?g/g Cr compared to other lesions in a time-varying Cox model adjusted for multiple confounding factors. In addition, the risk of reaching a 30% decline in eGFR was significantly higher in patients with M1 than in those with M0. Furthermore, patients with M1 had a greater decline of eGFR than patients with M0. However, steroid treatment in M1 lesion was not associated with improving clinical outcomes in the unmatched and propensity score matched cohort.

Conclusions: This finding may provide a rationale for using the Oxford classification as a guidance to initiate immunosuppression in the early stages of IgA nephropathy.

• KEY MESSAGES

• M1 has independently predictive role among the Oxford lesions in IgA nephropathy.

• Oxford classification should be defined during pathologic approach.

• Decision of starting immunosuppression according to the Oxford lesions.