Incidence of glomerulonephritis in the western part of Switzerland over the last decade

BACKGROUND Glomerulonephritis is a rare yet serious group of diseases with a high risk of progression to end-stage 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