Bleeding risk after native and transplant kidney biopsy - a single-centre observational study

Renal biopsies provide important and decisive information for diagnosis and therapy. Although biopsies are considered safe, bleeding complications remain a concern. We analysed the complication rate after kidney biopsies in native and transplant kidneys and their association with platelet function analyser bleeding time (PFA BT) and estimated glomerular filtration rate (eGFR).

This single-centre observational study included all patients who underwent an ultrasound-guided kidney biopsy at the University Hospital Basel from 2015 to August 2019. The main objective was to investigate the association of PFA BT with significant bleeding complications in kidney biopsies. Significant bleeding was defined as a haemoglobin decrease of >10 g/l within 48 hours or the need for transfusion after bleeding, according to the discretion of the treating physician. The pre-biopsy assessment included bleeding time using PFA BT, INR, thrombocyte count, and eGFR.

A total of 819 kidney biopsies-285 native and 534 transplant-were analysed. Complications occurred in 32 biopsies (3.9%): 18 (6.3%) in native and 14 (2.6%) in transplant kidneys. Bleeding was the most frequent complication in both groups. Overall, low eGFR (p = 0.01) and prolonged PFA BT (p = 0.02) were associated with bleeding complications. In native kidney biopsies, inpatient biopsy was associated with bleeding complications (p = 0.005), while in transplant kidney biopsies, bleeding complications were associated with time after transplantation (p <0.001), prolonged PFA BT (p <0.001), and diagnostic biopsies (p = 0.01). In the multivariable model, low eGFR was the only significant factor associated with bleeding complications (odds ratio 3.57, 95% confidence interval 1.76-7.23, p <0.001).

A low eGFR, especially below 30 ml/min, is associated with increased bleeding risk in native and transplant kidney biopsies.