Percutaneous Native Kidney Biopsy Complications in Diabetic Patients in the TRIDENT Cohort

KEY POINTS: In adults with diabetes, native kidney biopsy complications were uncommon across multiple US centers. Most events were minor; major bleeding was rare, but clinically meaningful. Obtaining an additional (research) core does not significantly increase the risk. BACKGROUND: Percutaneous kidney biopsy is essential for diagnosing kidney disease, but carries a risk of bleeding and other complications. Reported complication rates vary widely because of heterogeneity in outcome definitions. Patients with diabetes frequently have hypertension, vascular stiffness, and altered hemostasis, which may further influence biopsy safety. The multicenter Transformative Research in Diabetic Nephropathy study prospectively evaluated biopsy complications in adults with diabetes using standardized definitions across 21 sites from the United States. METHODS: We analyzed 408 native kidney biopsies from participants with diabetes enrolled in Transformative Research in Diabetic Nephropathy (2017-2025). Complications were classified as minor (hematoma, biopsy site pain, or hemoglobin drop), resource-intense (transfusion, radiologic or surgical intervention, or prolonged hospitalization), and major bleeding (≥2 g/dl hemoglobin decline, transfusion, or intervention). Logistic regression with site clustered robust errors was used to identify clinical and procedural associations with outcomes. RESULTS: Among 408 biopsies, 81 complications (20%) occurred, most commonly hematoma (15%); resource-intense events were infrequent (5%). Use of an 18-gauge (versus 16-gauge) needle was associated with lower odds of resource intense events (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.17 to 0.60). Procedures by fellows, hybrid teams, or interventional radiologists had higher odds than those by attendings (OR, 3.12-13.4). Renin-angiotensin system inhibitors use was independently associated with lower odds (OR, 0.13; 95% CI, 0.02 to 0.73). Female sex (OR, 4.88; 95% CI, 1.02-45.3) and postbiopsy hematoma (OR, 14.3; 95% CI, 3.66 to 74.5) were associated with major bleeding, whereas the number of passes correlated with hematoma formation, but not with adjusted major bleeding risk. CONCLUSIONS: In adults with diabetes, clinically significant biopsy complications were uncommon and were associated with procedural and operator factors rather than diabetes. Smaller gauge needles and experienced operators were associated with lower risk, whereas female sex and hematoma were associated with major bleeding. The higher overall complication rate mainly reflected comprehensive, prospective ascertainment of minor events, and supports standardized definitions and procedures to improve biopsy safety in diabetic kidney disease.