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Abstract: FR-PO637

Epidemiology of Rapidly Progressive Glomerulonephritis in Iceland

Session Information

Category: Glomerular Diseases

  • 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials

Authors

  • Sigurdarson, Magnus Thor, Haskoli Islands, Reykjavik, Iceland
  • Jonasdottir, Asta D., Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Hardarson, Sverrir, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Shcherbak, Konstantin, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Palsson, Runolfur, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
  • Indridason, Olafur S., Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
Background

Rapidly progressive glomerulonephritis (RPGN) is a serious presentation of glomerulonephritis (GN), defined as deteriorating kidney function over few days to three months. The average yearly incidence of RPGN in Iceland was 0.6/100,000 in the period 1983-2002. The aim of this study was to examine the epidemiology of RPGN in Iceland over the last two decades with regard to incidence and outcome.

Methods

This was a retrospective, population-based study of the period 2002-2021. We identified cases by searching SNOMED diagnosis codes in the database of the Department of Pathology at Landspitali – The National University Hospital of Iceland (LUH). We also searched for ICD-10 diagnosis codes indicative of RPGN in the LUH data warehouse. Nephrology services in Iceland are centralized at LUH, where all kidney biopsies in the country are performed. Demographic and clinical data were obtained from patients medical records. Annual incidence was calculated based on the population of Iceland each year (numbering 376,248 on January 1, 2022)

Results

Eighty-seven cases of RPGN were identified, 80 from biopsy data and additional seven by search for IDC-10 diagnosis codes. The median age was 58 years (range, 8- 89) and 51 (59%) were men. Pauci-immune GN accounted for 41 (47.1%) cases, 36 of which were positive and 5 negative for ANCA. Eighteen patients (20.7%) had anti-GBM disease and 25 (28.7%) immune-complex GN. The mean annual incidence of RPGN was 1.3/100,000 population. Increase in the incidence (per 100,000/year) from the first 5-year period to the last was noted for ANCA-associated vasculitis (from 0.41 to 0.67), ANCA-negative vasculitis (from 0.07 to 0.17) and for anti-GBM disease (from 0.21 to 0.33). The incidence decreased for immune-complex GN (from 0.55 to 0.11). Acute dialysis was needed in 30 cases (34.5%). At 6 months from diagnosis, 23 patients (26%) were dialysis-dependent and 11 (13%) had died.

Conclusion

The study suggests an increase in RPGN incidence in Iceland in the past 20 years. Since most patients with clinical presentation of RPGN are likely to be referred to nephrology and undergo a kidney biopsy, aging of the population or a true increase in incidence are the most likely explanations. Prognosis remains relatively poor and a high proportion of patients requires kidney replacement therapy.