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BACKGROUND: Glomerulonephritis is a rare yet serious group of diseases with a high risk of progression to endstage renal disease. For optimal healthcare planning, detailed epidemiological and demographic data are essential. Despite their clinical relevance, these data are largely lacking in Switzerland.OBJECTIVE: The objective of this study was to assess the incidence of the different forms of glomerulonephritis in the western part of Switzerland and its changes over the last 10 years, compared with international data.METHODS: We listed all renal biopsy reports analysed between 2007 and 2016 at the University hospital of Lausanne, the renal pathology reference centre of all hospitals in the cantons of Vaud, Fribourg, Valais and Neuchâtel. Biopsies with a first diagnosis of primary glomerulonephritis were included in the analysis. The incidence was calculated as the number of patients newly diagnosed with glomerulonephritis divided by the number of inhabitants of all the above-mentioned cantons during the year under review, as retrieved from the federal statistical office of Switzerland.RESULTS: We collected biopsy reports from 864 patients between 2007 and 2016; 168 biopsies met the inclusion criteria. The most common primary glomerulonephritis was IgA nephropathy at 32.7% of cases, followed by lupus nephritis (29.8%) and pauci-immune glomerulonephritis (11.9%). Overall, the mean incidence of glomerulonephritis was 1.3/100,000/year. Between 2007 and 2016, the incidence of all glomerulonephritis taken together remained stable. The same was true for the incidence of IgA nephropathy, lupus nephritis and pauci-immune glomerulonephritis. In contrast, we observed a trend towards higher creatinine levels, proteinuria and degree of interstitial fibrosis at diagnosis. CONCLUSION:The incidence of glomerulonephritis in the western part of Switzerland was low and remained stable over time, in line with European data.

Numerous cases of glomerulonephritis manifesting shortly after SARS-CoV-2 vaccination have been reported, but causality remains unproven. We studied the association between mRNA-based SARS-CoV-2 vaccination and new-onset glomerulonephritis using a nationwide retrospective cohort and case-cohort design. Data from all Swiss pathology institutes processing native kidney biopsies served to calculate incidence of IgA nephropathy, pauci-immune necrotizing glomerulonephritis, minimal change disease and membranous nephropathy. The observed incidence during the vaccination campaign (Jan to Aug 2021) was not different from the expected incidence based on the years 2015 to 2019 (incidence rate ratio 0.86, 95%-credible interval 0.73–1.02) and did not cross the upper boundary of the 95% credible interval for any month. Among 111 patients aged >18 years with newly diagnosed glomerulonephritis between January and August 2021, 38.7% had received at least one vaccine dose before biopsy, compared to 39.5% of the general Swiss population matched for age and calendar-time. The estimated risk ratio for the development of new-onset biopsy-proven glomerulonephritis was 0.97 (95% CI 0.66–1.42, P=0.95) in vaccinated vs. unvaccinated individuals. Patients with glomerulonephritis manifesting within 4 weeks after vaccine did not differ clinically from the rest of the cohort. Results were consistent across all types of glomerulonephritis with the possible exception of minimal change disease. In conclusion, vaccination against SARS-CoV-2 was not associated with new-onset glomerulonephritis in these two complementary studies. Most temporal associations between SARS-CoV-2 vaccination and glomerulonephritis are likely coincidental.