Tonsillectomy reduces recurrence of IgA nephropathy in mesangial hypercellularity type categorized by the Oxford classification.

BACKGROUND

In patients with IgA nephropathy (IgAN), recurrence after steroid pulse therapy is associated with reduced renal survival. However, the predictors of recurrence have not yet been clarified.

METHODS

All patients who received 6-month steroid pulse therapy from 2004 to 2010 in our four affiliated hospitals and achieved a reduction of proteinuria to <0.4 g/day 1 year after treatment were retrospectively evaluated. The primary outcome was proteinuria ≥1.0 g/day during follow-up or additional antiproteinuric therapy. Two histological classifications were evaluated, the Oxford Classification with a split system and Japanese histological grades (HGs) with a lumped system.

RESULTS

During a median follow-up of 3.4 years, 27 (26.7 %) of the 101 patients showed recurrence. Multivariate analysis showed that HG was the only significant predictor of recurrence, with HG 2+3+4 vs HG 1 having a hazard ratio of 7.38 (95 % confidence interval 1.52-133). Furthermore, in patients with mesangial hypercellularity according to the Oxford Classification, cumulative rate of recurrence-free survival was greater in patients with steroid therapy plus tonsillectomy compared with those who received steroid therapy alone (Log-rank test, P = 0.022). However, this association was not observed in patients without mesangial hypercellularity.

CONCLUSIONS

HG is a novel predictor of recurrence after steroid pulse therapy in patients with IgAN. Moreover, the combination of steroid pulse therapy plus tonsillectomy may indicate a lower risk of recurrence in patients with mesangial hypercellularity, as defined by the Oxford Classification.