Clinical parameters predicting complications in native kidney biopsies

Background. Renal biopsies are essential in nephrology but they are invasive and complications can occur. The aim of this study was to explore clinical parameters that can be used as predictors for biopsy complications. Methods. Clinical parameters such as demographics, biopsy indications, serology, comorbidities and clinical chemistry were retrieved from a regional biopsy registry between 2006 and 2015 and from a nationwide registry between 2015 and 2017. Clinical data before biopsy were compared with data on major biopsy complications. Fisher's exact and v2 tests were used and odds ratios (ORs) with 95% confidence intervals (CIs) were presented. Univariate and multiple binary logistic regression analyses were performed with complications as outcome. A two-sided P-value <0.05 was considered significant. Results. In total, 2835 consecutive native kidney biopsies were analysed (39% women and 61% men, median age 57 years). No death and nephrectomy due to biopsy complications were registered. The frequency of major biopsy complications was 5.65%. In the multiple logistic regression, the risk for complications increased in women [OR 1.51 (95% CI 1.08-2.11)] and decreased with age: 45-64 years age group [OR 0.66 (95% CI 0.44-0.99)] and >74 years age group [OR 0.51 (95% CI 0.27-0.96)]. Among comorbidities, patients with diabetes mellitus type 2 [OR 2.07 (95% CI 1.15-3.72)] and non-ischaemic heart disease [OR 3.20 (95% CI 1.64-6.25)] had a higher risk for major biopsy complications. Conclusions. Female gender, younger age (<= 44 years), diabetes mellitus type 2 and non-ischaemic heart disease were found as risk factors for major biopsy complications.