To investigate the effects of low-dose glucocorticoid combined with optimized supportive therapy on renal function and proteinuria in patients with recurrent or de novo IgA nephropathy (IgAN) after kidney transplantation.

A retrospective analysis was conducted on the clinical data of 36 patients with biopsy-confirmed post-transplant IgAN at Jiangxi Provincial People′s Hospital from September 2021 to December 2024. Based on whether a low-dose glucocorticoid regimen was administered, the patients were divided into the low-dose glucocorticoid group (n=17) and the control group (n=19). The control group received optimized supportive therapy alone. The low-dose glucocorticoid group received low-dose prednisone (0.5 mg·kg^-1·d^-1) for 8 weeks on top of the optimized supportive therapy, followed by a monthly reduction of 5 mg, until a long-term maintenance dose of 10 mg/d was reached after 6 months. Serum creatinine (Scr), 24-hour urinary protein, and allograft survival rates before and after treatment were compared between the two groups. Normally and non-normally distributed quantitative data were compared using the Student′s t-test and the Mann-Whitney U test, respectively. Categorical data were compared using the Pearson′s chi-square test or Fisher′s exact test. Odds ratios (ORs) were used to assess relative risk. Survival analysis was performed using the Kaplan-Meier method, and survival rates were compared using the log-rank test. A value of P<0.05 was considered statistically significant.

There were no statistically significant differences between the two groups in baseline parameters including age, sex, donor type, donor age, number of HLA mismatches, anti-thymocyte globulin (ATG) induction therapy, time from transplantation to biopsy, Oxford classification pathological scores, and baseline levels of Scr and 24-hour proteinuria at the time of biopsy (t/χ²/Z=-0.786, 0.001, 0.001, -0.485, 0.571, 0.358, 159, -0.786, 0.001, 0.001, -0.485, 0.571, 0.358, 159, all P>0.05). At the end of follow-up, the Scr level in the low-dose glucocorticoid group was significantly lower than that in the control group [(117.8±30.2) vs. (156.7±19.2) μmol/L, t=4.248, P<0.05]. The 24-hour urinary protein also decreased significantly [0.5 (0.2-1.6) vs. 1.5 (0.3-2.7) g/d, Z=83, P<0.05]. The proportion of patients achieving 24-hour proteinuria <0.3 g/d was higher in the low-dose glucocorticoid group than in the control group (8/17 vs. 4/19), though the difference was not statistically significant (χ²=2.731, P>0.05), with an OR of 3.33 (95%CI: 0.78-14.31). In the control group, there were no significant changes in Scr and 24-hour urinary protein levels before and after treatment (t/Z=-0.152/197, all P>0.05). In contrast, the Scr and 24-hour urinary protein levels in the low-dose glucocorticoid group after treatment were significantly lower than those before treatment (t/Z=2.125/32, all P<0.05). In the low-dose glucocorticoid group, 3 cases of hyperglycemia and 2 cases of mild pulmonary infection occurred, all of which recovered after management; no adverse reactions occurred in the control group. The 3-year cumulative allograft survival rates in the low-dose glucocorticoid group and the control group were 92.9% and 81.4%, respectively, with no statistically significant difference (χ²=0.522, P>0.05).

Low-dose glucocorticoid combined with optimized supportive therapy can significantly improve renal function and proteinuria control in patients with IgAN after kidney transplantation, and the adverse reactions are manageable.