Supplementary Material for: Relapse Risk in Patients with Membranous Nephropathy after Inactivated COVID-19 Vaccination

Background Although there have been reports of relapse or worsening of membranous nephropathy after receiving vaccines against coronavirus disease 2019 (COVID-19), the causal relationship or association between them has not been established. This study aimed to investigate the occurrence of relapse or worsening of membranous nephropathy following inactivated COVID-19 vaccination. Methods Patients who had been diagnosed with membranous nephropathy before receiving their first dose of vaccination, or before March 1, 2021 for unvaccinated patients, were included in the study. All patients were monitored at the Membranous Nephropathy Clinic of Huashan Hospital, Fudan University. The reasons for not receiving vaccines were investigated. The impact of COVID-19 vaccination on membranous nephropathy was assessed by comparing the relapse or worsening of membranous nephropathy within 12 months in vaccinated and unvaccinated patients with proteinuria <3.5g/d. The baseline variables were balanced using cardinality matching. Results A total of 353 patients with membranous nephropathy were included in the study, with 186 (53%) having received inactivated COVID-19 vaccines. Among the 167 unvaccinated participants, 114 (68%) expressed concerns about the possibility of disease relapse, and 47 (28%) were worried about the vaccine’s efficacy due to their immunosuppressive therapy. Of the 239 participants with proteinuria <3.5g/d, 152 were vaccinated, and 16 (11%) experienced a relapse or worsening of the disease during the follow-up period, which was similar to the 14 (16%) observed in the unvaccinated group. Following cardinality matching, there was no difference in the rate of relapse or worsening between the two groups, with 10 (13%) in the vaccinated group and 11 (15%) in the unvaccinated group (Hazard ratio 0.98, 95% confidence interval 0.42-2.33). Conclusion Getting the inactivated COVID-19 vaccine did not lead to a higher risk of relapse or worsening in patients with membranous nephropathy.