Characteristics and Outcomes of IgA Nephropathy in the Canadian Province of Manitoba
Bibliographic record
Abstract
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 reninangiotensin 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. Conclusions: 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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.006 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".