Risk Factors for Infection After Transrectal Prostate Biopsy: A Population-based Register Study.

Background and objective: Infection after transrectal prostate biopsy (TPBx) is a well-known risk. A comprehensive investigation of risk factors may identify measures for safe TPBx as an alternative to a change in biopsy route. The aim of this study was to identify risk factors for infection after TPBx. Methods: We included all outpatient TPBx cases in Region Kronoberg, Sweden, from January 2010 to December 2019. The primary outcome was post-TPBx infection, defined as prescription of antibiotics indicated for urinary tract infection (UTI) or inpatient care for infection within 30 d. We analysed the following factors in relation to post-TPBx infection: age, diabetes mellitus, prostate cancer diagnosed at index biopsy, previous prostate biopsy, two or more biopsies in the past 24 mo, a positive urine culture, two or more negative urine cultures (UCs) in the past 24 mo, antibiotic treatment grouped as four types, and medication for benign prostatic hyperplasia (BPH). Logistic regression was used to calculate odds ratios (ORs). Key findings and limitations: Of 5788 TPBx procedures in 4040 patients, 405 (7.0%) led to an infection and 170 (2.9%) to inpatient care for infection. Risk factors for post-TPBx infection (ORs 1.5-2.5) were diabetes mellitus, antibiotic treatment for a UTI, fluoroquinolone treatment, and a positive urine culture. Weaker risk factors (ORs 1.3-1.5) were non-UTI antibiotic treatment, BPH medication, and negative UCs before TPBx. Conclusions and clinical implications: Our results confirm that diabetes mellitus and previous UTI are risk factors for infection after TPBx. Lower urinary tract symptoms and treatment with any kind of antibiotic were associated with infection, which has not been previously reported. Patient summary: In a large population-based study from Sweden, we investigated which clinical factors increase the risk of an infection after transrectal prostate biopsy. Our results confirm that diabetes and a previous urinary tract infection are risk factors. We also found two new factors associated with the risk of infection after biopsy: lower urinary tract symptoms and any antibiotic treatment.