Abstract: FR-PO0420
Kidney Biopsy in Patients with Diabetes, AKI, and Heavy Proteinuria
Session Information
- AKI: Biomarkers, Diagnostics, and Risk Prediction
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Jahanshahi, Atousa, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, United States
- Zuckerman, Jonathan E., University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, United States
- Nicholas, Susanne B., University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, United States
Background
Kidney biopsy is indicated in patients with diabetes mellitus (DM) with atypical features suggestive of non-diabetic kidney disease (NDKD), including acute kidney injury, heavy proteinuria, and absence of diabetic retinopathy (DR). However, real-world biopsy utilization and diagnostic yield across this clinical cascade remain poorly characterized.
Methods
We conducted a retrospective electronic health record–based analysis using the UCLA i2b2 database (January 2016–January 2026) to evaluate biopsy utilization and diagnostic yield for NDKD. Adults with DM, without pre-existing DR or diabetic nephropathy (DN) were followed through a cascade: AKI → AKI with heavy proteinuria → biopsy → biopsy-confirmed NDKD. Heavy proteinuria was defined as 24-hour urine protein ≥3.5 g/day, urine protein ≥0.3 g/dL, or urine protein-to-creatinine ratio ≥3500 mg/g. Outcomes were biopsy utilization and NDKD yield, stratified by demographics and comorbidities.
Results
Among 160,385 patients with DM, without DR or DN, 40,297 (25.1%) developed AKI. Of these, 7,402 (18.4%; 4.6% of total cohort) had concurrent heavy proteinuria. Only 1,297 (17.5%) underwent kidney biopsy, and 125 (9.6%) had biopsy-confirmed NDKD (number needed to biopsy: 10.4). Heavy proteinuria rates were consistent across comorbidities (21–25%), contrasting with variation in biopsy utilization (14.8–21.0%) and narrower variation in NDKD yield (8.3–14.7%). This was most striking across age groups: biopsy utilization varied nearly 11-fold, from 58.1% (ages 18–34) to 5.1% (ages 85–89), while NDKD yield varied less than 2-fold (7.6–15.7%). Females had higher NDKD yield than males (11.6% vs. 8.3%). Black patients had the highest AKI incidence (34.7%) but lower observed NDKD yield (4.7%), whereas Asian patients had the highest yield (13.1%). Middle Eastern or North African patients had high proteinuria rates (23.5%) but low biopsy utilization (10.1%). Complicated hypertension had the highest biopsy rate (21.0%) but lower yield (9.7%), while hypothyroidism had the lowest biopsy rate (14.8%) and yield (8.3%).
Conclusion
In patients with DM, AKI and heavy proteinuria, kidney biopsy is performed less than 20% of the time, yielding NDKD in ~10%. Findings suggest systematic underdiagnosis of potentially treatable NDKD, particularly in older adults. Improved risk stratification is needed to optimize biopsy practice.