Population-Level Study of IgAN Using a Biopsy Registry

Most studies of IgA nephropathy (IgAN) have focused on single- or multi-center cohorts and included criteria and selection bias that limit the generalizability of the results. During a poster session at ASN Kidney Week 2024, Sinead Stoneman and colleagues reported on the methodology they used to study outcomes of adult IgAN at the population level in a large, multi-ethnic Canadian province, British Columbia. Their poster was titled Studying IgA Nephropathy at a Population Level over a 21-Year Period.

Study participants were identified using the British Columbia Glomerulonephritis Registry, which includes any biopsy with glomerulonephritis and links to health care administrative databases to capture patient comorbidities, laboratory data, treatment, and outcomes.

The population-level cohort study included 1,382 adults aged ≥18 years with primary IgAN during a 21-year period from 2000 to 2020. The median age of participants at biopsy was 44.3 years. Proteinuria was available for 88.1% of participants and eGFR was available for 92.4%. Proteinuria was 1.4 g/day and eGFR was 54.1 ml/min/1.73m² at biopsy. There were 12 (IQR, 4, 25) proteinuria measurements per patient during follow-up and 19 eGFR (IQR, 9, 38) measurements. Proteinuria was measured every 2.8 months (IQR, 1.1, 4.8), while eGFR was measured every 1.2 (IQR, 0.4, 3.0) months. The 20-year risk of ESRD was 49.4% and risk of death was 15.6%.

To conclude, the researchers found that using a provincial biopsy registry linked with administrative databases to study IgAN at the population-level was practical in this setting. Treatment patterns, clinical outcomes, and health care utilization should be studied in the future.

Source: Stoneman S, Han J, Barratt J, Atiquzzaman M, Barbour S. Studying IgA nephropathy at a population level over a 21-year period. FR-PO860. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2024; October 25, 2024; San Diego, California.