Predictors of kidney biopsy complication among patients with systemic lupus erythematosus

Kidney biopsy is essential for the diagnosis and management of lupus nephritis. The risk of bleeding complication, however, is not defined in the systemic lupus erythematosus population. A retrospective cohort study was conducted to determine predictors of major and minor complications among patients with systemic lupus erythematosus undergoing percutaneous ultrasound-guided kidney biopsy. Major complications included bleeding necessitating intervention, hypotension requiring vasopressors or higher level of care or death. Minor complications included moderate or large (≥ 4cm in largest diameter) perinephric hematoma, gross hematuria or voiding difficulties. All patients were observed for at least 23 h post-procedure. The overall incidence of bleeding was 10.5% (2.7% major, 7.8% minor). Adjusted logistic regression showed that for every 10,000 cells/mm3 decrease in platelet count, risk for major and any complication increased by 27% (odds ratio 1.27; 95% confidence intervals 1.06-1.51; p=0.01) and 8% (odds ratio 1.08; 95% confidence intervals 1.02-1.15; p=0.01), respectively. Patients with a platelet count <150,000 cells/mm3 were 30 times more likely to experience a major complication (p=0.002). Other candidate predictors, including steroid exposure, kidney function, hematocrit and histopathology, were not significant. Kidney biopsies are well tolerated in patients with systemic lupus erythematosus. However, patients with pre-biopsy platelet counts <150,000 cells/mm3 are at markedly increased risk for a major bleeding complication.