Kidney Biopsy Quality Improvement Study

Background: Kidney biopsy is essential for definitive diagnosis of kidney disease. Recent data indicate an increasing biopsy miss rate and inadequacy. Most retrospective analyses report kidney biopsy major complications in 1-2% of patients, and inadequate tissue for diagnosis in 14%.The study aimed to review the adequacy and complications of kidney biopsy. Methods: A retrospective single-center quality improvement study of patients who underwent renal biopsies between January-2020 and December-2023. Univariate and binomial logistic regression was used to predict adequacy and complications. Results: Study included 181 patients,72(39.8%) were male.Mean age and BMI was 52.9±17.3 years and 29.5±7.8 kg/m2. Mean baseline serum creatnine and hemoglobin(Hb) was 2.36±1.75 mg/dL and 11.25±2.4 g/dL.28.8% patients had stage 2 or 3 AKI.Mean eGFR in CKD stages <3 was 32.18 ± 15.94 ml/min.5.5% were on active anticoagulation.18 Gauge needle was used in all biopsies. 126(69.6%) biopsies were determined to be adequate(defined >= 10 glomeruli on LM, 1 glomerulus on IF and EM). Sex, age, BMI, length of kidney, and creatinine did not predict the likelihood of adequate sample. Total number of major complications was 11(6.1%) with 4(2.2%) requiring embolization or angiography,5(2.7%) requiring transfusions <7 days, and 2(1.1%) requiring both. Among age, sex, creatinine, platelet, INR, number of passes, total core length, active anticoagulation, AKI, baseline Hb, pre-biopsy SBP and DBP, and radiologist, total core length predicted major complications on univariate analysis(p=0.04)and just missed significance on logistic regression(p=0.06). Conclusion: One-third of kidney biopsies were inadequate with rare but considerable major complications. No specific predictors linked current biopsy protocols to adequacy. Total core length correlated to major complications. A shallower, wider biopsy with 16G needle would strike a balance between adequacy and minimizing complication. This study is limited by small sample size.