Predicting post renal biopsy complications

At our institution, kidney biopsies are performed by an interventional nephrologist with standardized guidelines using real-time ultrasound. We hypothesized that patient factors could predict post biopsy complications. We did a retrospective review of 100 patients who underwent renal biopsy. Prebiopsy data obtained included demographics, blood pressure, laboratory studies, and kidney size. Biopsy procedure information was also recorded. Complications and post biopsy imaging was noted. A minor complication was defined as one not requiring intervention while a major complication required interventions like readmission or blood transfusion. The average age was 47 years, 41 were men, 51 were black, 30 had diabetes, 42 were obese, and 81 had hypertension. Twenty-six patients had a complication; 14 minor and 12 major including 1 nephrectomy. Factors predictive of a complication were thrombocytopenia (p=0.002) and inpatient status (p=0.04). Drop in hemoglobin at 6 hours was moderately sensitive and specific for a bleeding complication with an ROC of 0.723. Thrombocytopenia and inpatient status are risk factors for complications after renal biopsy. Serum creatinine, obesity, blood pressure, kidney size, needle size, and number of passes were not predictive of a major complication in our study.