Renal outcome in Covid-19 infection in a cohort of patients with glomerular disease: a single-center retrospective study

Background. SARS-CoV-2 virus pandemia had an important impact on global health, affecting millions of individuals worldwide. Although primarily considered a respiratory illness, COVID-19 has been associated with various systemic manifestations, including renal complications. Glomerulonephritis (GN) are immunologically mediated renal disorders and emerged as potential targets of both SARS-CoV-2 infection and SARS-CoV-2 vaccination. Aim of the study. This study aimed to evaluate renal outcomes (serum creatinine level and 24h proteinuria) in a cohort of patients with glomerular disease following SARS-CoV-2 infection and/or vaccination, also assessing for the possible onset of Acute Kidney Injury (AKI). Different therapeutic approaches are also taken into account, and it is assessed whether the administration of ACE inhibitors and ARBs exerts a protective effect on renal outcomes compared to other pharmacological treatments employed. Materials and Methods. The study included all patients under nephrology follow-up at the Nephrology Unit of the University Hospital of Padua, with a histologically confirmed diagnosis of glomerulopathy or, in the case of membranous nephropathy, serological positivity for anti-PLA2R antibodies. A retrospective, single-center study design was adopted, covering the observation period from early 2020 to the end of 2023. The study was approved by the Ethics Committee for Experimental Research of Azienda Ospedaliera di Padova, protocol number 6288/AO/25, May 2025. Renal outcomes were assessed through serial measurements of serum creatinine levels (µmol/L) and 24-hour proteinuria (g/day) recorded before infection/vaccination and during follow-ups. Variations in these parameters were correlated with either SARS-CoV-2 infection (Group 1) or vaccination (Group 2), or with the administration of ACE inhibitors/Angiotensin receptor blockers (ARBs) compared to other therapies (Group 3). A median interval (ΔT=42 days for infection, 45 for vaccine) was established for evaluating post-exposure laboratory data. Statistical analyses were conducted using non-parametric tests. Pre- and post-exposure values of creatinine and proteinuria were compared using the Wilcoxon signed-rank test and the Mann-Whitney U test, considering statistically significant a p-value < 0.05. Results: A total of 105 patients were enrolled, with a median age of 48 years (20–84). During the observation period, 51 patients (48.57%) contracted the infection, 31 (60.78%) male and 20 (39.21%) female. In the group of infected patients the median pre-infection creatinine level was 94 (55-400) µmol/L, while the post-infection median was 106 (52-1360) µmol/L (p=0.005). 49 out of 105 patients (46.66%) were with active glomerulonephritis. Among these 49 patients, 28 (57.14%) contracted the infection and 33 (67.34%) were vaccinated (8 prior to infection). A clinical deterioration (SCr ↑ 1.5x OR 24h UP ↑ 2x) after infection was observed in 11 (39.28%) patients (3 with vaccine prior to infection). The median serum creatinine level among the infected with active GN before infection was 97.5 (62-400) µmol/L, rising to 130 (60-1360) µmol/L after infection (p = 0.01). Regarding SARS-CoV-2 vaccination, 68 patients (64.76%) received at least one dose. The median pre-vaccination creatinine level was 92 (55-270) µmol/L, while the post-vaccination median was 99 (55-278) µmol/L (p=0.004). The same trend was observed about proteinuria level with the median pre-vaccination level of 0.925 (0.05-12.69) g/day, while the post-vaccination median increased to 1.55 (0.064-20.03) g/day (p=0.037). In our cohort we identified 8 patients out of 45 (17.78%), 7 male and 1 female, that developed AKI in the infected group [three of them (37.5%), two male and one female, remained in end stage renal disease (ESRD)]. 9 patients developed AKI in the vaccination group of 46 (19.57%), 7 male and 2 female. 3 patients were overlapping in both groups.