Clinical effectiveness of steroid pulse therapy combined with tonsillectomy in patients with immunoglobulin A nephropathy presenting glomerular haematuria and minimal proteinuria

Aim: The effectiveness of steroid pulse therapy combined with tonsillectomy (ST) has been shown in immunoglobulin A nephropathy (IgAN) patients with moderate or severe urinary abnormalities. The present study aimed to clarify whether the effectiveness may be extrapolated to IgAN with minor urinary abnormalities, and whether the effectiveness may depend on the histological severity with minor urinary abnormalities. Methods: Data on 388 IgAN patients diagnosed by renal biopsies between 1987 and 2000 in Sendai Shakaihoken Hospital, who presented glomerular haematuria and minimal proteinuria (< 0.5 g/day) at baseline, were analyzed. Cox regression was used to examine associations between baseline use of ST and subsequent clinical remission (CR), defined as negative proteinuria by dipstick and urinary erythrocytes of less than 1/high-power field. The instrumental variable method was also used to overcome confounding by treatment indication. Results: During a median follow up of 24 months, we observed 170 CR cases. Patients receiving ST were younger and showed a better case-mix profile. Patients with ST had a significantly higher rate of CR than patients without tonsillectomy or steroid pulse in an unadjusted (hazard ratio (HR) = 5.51, 95% confidence interval (CI) = 3.33-9.12, P < 0.001) or adjusted Cox model (HR = 4.65, 95% CI = 2.43-8.88, P < 0.001). Less severe histological findings were substantially associated with higher CR rate in ST group. Adjusting for confounding by treatment indication showed an attenuated but still significant effect of ST (HR = 3.10, 95% CI = 2.02-4.77, P < 0.001). Conclusion: ST significantly increased the probability of CR in IgAN patients with glomerular haematuria and minimal proteinuria, and it was more effective in those with less severe histological findings.