Diabetic Kidney Biopsies Deemed Safe for Clinical Practice
Percutaneous kidney biopsy is a safe procedure for patients with diabetes, according to a recent prospective observational cohort study published in the Clinical Journal of the American Society of Nephrology. Researchers found that procedural factors—such as operator experience and needle gauge—are more significant indicators of complication risks than the patient’s underlying diabetic status.
Tracking Outcomes Across the TRIDENT Project
The study, part of the TRIDENT project, tracked 408 native kidney biopsies performed between 2017 and 2025 across 21 U.S. academic medical centers. The cohort included adults with type 1 or type 2 diabetes with a mean age of 54.
Data revealed that complications occurred in 20% of the cases, though the vast majority were minor. Hematoma was the most frequent complication at 15%, followed by biopsy site pain at 4%, prolonged hospitalization at 3%, and blood transfusion at 2%. Overall, resource-intensive events—defined as those requiring transfusion, radiologic or surgical intervention, or prolonged hospital stays—occurred in 5% of biopsies.
The Critical Impact of Needle Size and Operator
The research team identified specific variables linked to higher rates of resource-intensive events. Biopsies performed by nephrology fellows or interventional radiologists carried a higher risk compared to those conducted by attending nephrologists. Additionally, the use of a 16-gauge needle was associated with a higher risk of resource-intensive events compared to an 18-gauge needle.
“Although the smaller needle sometimes required an additional pass to obtain adequate tissue, the additional pass did not increase the risk of major bleeding,” said Katalin Susztak, MD, PhD, a professor of medicine and genetics at the University of Pennsylvania. This suggests that the size of the needle is a more critical safety factor than the total number of passes performed.
Gender Disparities in Bleeding Risks
Major bleeding occurred in 3% of the studied biopsies. The data indicated that women were more likely to experience major bleeding than men. Furthermore, patients who developed a post-biopsy hematoma were at a significantly higher risk for major bleeding events.
While the exact reasons for the increased risk in women remain under investigation, researchers noted that factors such as body habitus, kidney size, vascular anatomy, or baseline hemoglobin levels likely play a role. According to the study, these findings should not discourage clinicians from performing biopsies on female patients when clinically indicated.
Standardizing Care for Diabetic Nephropathy
The researchers emphasize that diabetes itself should not be considered a barrier to performing a necessary kidney biopsy. Because the biopsy remains the gold standard for diagnosing kidney disease, the focus should remain on optimizing procedural techniques. The study authors advocate for further multicenter research to standardize reporting, improve operator training, and refine post-biopsy monitoring protocols to ensure the highest safety standards for patients with diabetic kidney disease.