Risk vs. Reward: Impact of Kidney Biopsies on the Management of Critically Ill Patients

Background: Kidney biopsy is the gold standard for diagnosing many renal diseases, providing crucial information that guides treatment decisions and potentially improves patient outcomes. However, these benefits must be balanced against the risks, particularly in critically ill patients, who are at higher risk of complications due to unstable hemodynamics and coagulation abnormalities. Here we examine the safety and benefit of kidney biopsies in critically ill patients compared to others. Methods: In participants enrolled in the Yale Kidney biobank, we compared the safety and benefit of kidney biopsies between those in the ICU, inpatient wards, and outpatients. The benefit was changes in management, defined as the initiation of steroids, immunosuppressive agents, pheresis, or drug discontinuation post-biopsy. Secondary outcomes included changes in diagnosis, the need for short-term hemodialysis, and chronic hemodialysis dependence. We also assessed safety outcomes using a composite measure of medium/large hematomas, drops in hemoglobin, the need for additional imaging, and interventional radiology procedures. Results: Of the 748 participants, 30 were in the ICU, 202 were inpatient, and 516 were outpatients (Table). Kidney biopsies in the ICU group had a significant impact on management, with 18/30 (60%) of the biopsy results leading to changes in or avoidance of immunosuppressive therapy relative to what would have been the standard of care based on the pre-biopsy diagnosis. The remaining biopsies either confirmed the pre-biopsy diagnosis or resulted in a change between two non-treatment-requiring processes. Safety events were observed in all groups, with the highest rate in the critically ill. Conclusion: Kidney biopsies in the critically ill can significantly impact management but may carry a higher risk of safety events. This risk needs to be compared to the potential benefit and should not be a barrier to a biopsy in select patients.