Abstract

Background

Glomerular hematuria and proteinuria are typical manifestations of IgA nephropathy (IgAN). However, hematuria severity is not considered a useful marker of the potential benefits of corticosteroid administration as proteinuria severity only is included in the current guidelines.

Methods

In this retrospective cohort study, we enrolled 133 patients diagnosed with IgAN through biopsy. We calculated the 2-year estimated glomerular filtration rate (eGFR) slope (mL/min/1.73m²/year) and eGFR trajectory after methylprednisolone pulse therapy using mixed effects models stratified by the Oxford classification and three categories of pre-treatment hematuria: mild [urinary red blood cells (URBCs) < 10/high-power field (HPF)], moderate (URBCs 10–30/HPF), and severe (URBCs ≥ 30/HPF).

Results

The severe pre-treatment hematuria group showed a significantly higher likelihood of having crescents (odds ratio (OR), 4.3; 95% confidence interval (CI), 1.7–10.9). In the longitudinal analysis of 103 patients, most of whom underwent tonsillectomy, the severe pre-treatment hematuria group had a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than the mild and moderate hematuria groups (mild, -0.52 ± 1.97; moderate, -0.32 ± 1.99; severe, 1.44 ± 3.20 mL/min/1.73m²/year). Patients with C2 scores showed a significantly higher 2-year eGFR slope after methylprednisolone pulse therapy than those with C0 and C1 scores (C0, -0.38 ± 1.74; C1, 0.81 ± 3.02; C2, 3.29 ± 3.68 mL/min/1.73m²/year). Analyses of eGFR trajectory after methylprednisolone pulse therapy revealed that the eGFR improved only in patients with severe pre-treatment hematuria or C2 score (P_interaction with time < 0.001).

Conclusions

The eGFR is likely to improve after methylprednisolone pulse therapy with tonsillectomy in IgAN patients with severe pre-treatment hematuria or a high percentage of crescents.

Graphic abstract