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Kidney Week

Abstract: TH-PO620

Characteristics and Outcomes of IgA Nephropathy in the Canadian Province of Manitoba

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Barr, Bryce, University of Manitoba Max Rady College of Medicine, Winnipeg, Manitoba, Canada
  • Harasemiw, Oksana, University of Manitoba Max Rady College of Medicine, Winnipeg, Manitoba, Canada
  • Gibson, Ian W., University of Manitoba Max Rady College of Medicine, Winnipeg, Manitoba, Canada
  • Tremblay-Savard, Olivier, University of Manitoba Faculty of Science, Winnipeg, Manitoba, Canada
  • Tangri, Navdeep, University of Manitoba Max Rady College of Medicine, Winnipeg, Manitoba, Canada
Background

Immunoglobin A (IgA) nephropathy is a common primary glomerulonephritis with variable clinical presentation. The aim of the current study was to characterize the population of patients with IgA nephropathy in the Canadian province of Manitoba.

Methods

In this retrospective, population-based cohort study, we identified all patients with biopsy-proven IgA nephropathy in the province of Manitoba, Canada between July 1, 2002 and December 31, 2019. Natural-language processing software was used for data extraction from pathology reports, which was then linked to administrative data via the Manitoba Centre for Health Policy. Descriptive statistics are presented to describe the patient population.

Results

We identified 366 patients (mean age at biopsy 43.2 years, 39.6% females). Mean estimated glomerular filtration rate (eGFR) at biopsy was 50 mL/min/1.73m2, and mean urine albumin-to-creatinine ratio was 167.7 mg/mmol. Of the 122 patients with Oxford scores, 29 (23.8%) had M1, 46 (37.7%) had E1, 107 (87.7%) had S1, 29 (23.9%) and 43 (35.3%) had T1 and T2, respectively, while 33 (27%) had either C1 or C2. When stratifying by income quintiles, 31.7% of patients were in the lowest income quintile versus 9.6% in the highest. Comparing eras (2002-2010 versus 2011-2019), receipt of disease-modifying treatment within 6 months of biopsy remained stable for renin-angiotensin system inhibitors (69.6 vs 69.7%), anti-blood pressure medications (57.8 vs 60.6%) and glucocorticoids (23.0 vs 20.4%). Statin use increased significantly between periods (13.3% vs 29.0%, p<0.001). Patients were more likely to receive glucocorticoids if they had Oxford scores M1 versus M0 (41.4 vs 18.3%, p=0.01), E1 versus E0 (37.0 vs 15.8%, p=0.0078), or C1+2 versus C0 (51.5 vs 13.5%, p<0.0001). Over a median of 5.6 years of follow-up, 163 (44.5%) patients developed kidney failure and 69 (18.9%) patients died.

Conclusion

In this cohort, IgA nephropathy was associated with substantial risk of kidney failure and mortality. This study demonstrated the feasibility of using natural language processing as a data extraction technique, and will facilitate further epidemiologic research in this cohort. The study was limited by small sample size, incomplete Oxford scoring and lack of blood pressure data.

Funding

  • Government Support – Non-U.S.