Association between tonsillectomy plus steroid pulse therapy and renal outcomes in patients with IgA nephropathy: a retrospective cohort study.

Abstract

Background: IgA nephropathy (IgAN) is the most common disorder in chronic glomerulonephritis, and various treatment methods have been established. Tonsillectomy and steroid pulse therapy (TSP) are widely performed in Japan. However, their correlation with renal outcomes remains unclear. In this study, we aimed to examine the association between renal prognosis and steroid pulse therapy with or without tonsillectomy.

Methods: In this retrospective cohort study, we identified patients diagnosed with IgAN between April 2002 and March 2021 using a Japanese healthcare records database. We selected patients with a prescription history of methylprednisolone for three consecutive days within one year of diagnosis and an estimated glomerular filtration rate (eGFR) of 30 mL/min/1.73 m² or above. We categorized the patients into TSP and steroid pulse therapy (SP) groups based on whether they underwent tonsillectomy within one year of diagnosis. The primary outcome was the composite outcome of a 30% decline in eGFR and initiation of dialysis, and the secondary outcomes comprised the composite outcome of end-stage renal failure and initiation of dialysis and eGFR slope. Inverse probability of treatment weighting (IPTW) using propensity score, Kaplan-Meier survival analysis, and weighted Cox regression analysis by applying IPTW were performed.

Results: Overall, 550 patients were eligible for the main analysis, and approximately 40% underwent tonsillectomy within 1 year of IgAN diagnosis: 221 in the TSP group and 329 in the SP group. The primary outcome did not differ between the groups (hazard ratio, 0.58; [95% confidence interval: 0.22-1.54]; P = 0.28). The groups did not differ in terms of the secondary outcomes.

Conclusions: Although we could not demonstrate the effectiveness of TSP on renal prognosis in patients with IgAN, this study may have been underpowered, and there are certain limitations due to the information available from the database, we were able to evaluate the association of TSP on renal outcomes using real-world data.

Clinical trial number: Not applicable.