Combined predictive accuracy of inflammatory and hematologic indicators for urinary tract-related bloodstream infection.

OBJECTIVES: Urinary tract-related bloodstream infection (UT-BSI) is a severe complication of hospital-acquired urinary tract infection (HA-UTI), yet its early diagnosis remains challenging. This study aimed to evaluate the combined predictive efficiency of inflammatory and hematologic indicators for UT-BSI. METHODS: A retrospective analysis was conducted on patients with HA-UTI admitted to non-critical internal medicine wards between July 2023 and June 2025. Patients were categorized into bloodstream infection (BSI) and non-BSI groups based on positive blood cultures yielding pathogens identical to those isolated from urine samples. Within 6 hours of blood culture sampling, levels of interleukin-6 (IL-6), procalcitonin (PCT), C-reactive protein (CRP), white blood cell count (WBC), platelet count (PLT), and neutrophil-to-lymphocyte ratio (NLR) were measured. RESULTS: A total of 279 HA-UTI patients were enrolled for analysis, comprising 165 in the non-BSI group and 114 in the BSI group. The BSI group exhibited significantly elevated levels of IL-6 (36.74 vs. 28.36 pg/mL, P < 0.001), PCT (0.72 vs. 0.54 ng/mL, P < 0.001), CRP (50.56 vs. 38.18 mg/L, P < 0.001), WBC (12.43 vs. 11.59 × 109/L, P = 0.007), and NLR (10.85 vs. 9.23, P < 0.001), while PLT were lower (177.42 vs. 185.36 × 109/L, P = 0.007). Multivariate logistic regression identified indwelling catheter (P = 0.018), quick sequential organ failure assessment ≥ 2 (P = 0.030), IL-6 (P < 0.001), PCT (P < 0.001), CRP (P < 0.001), and NLR (P < 0.001) as independent risk factors for UT-BSI. The combined predictive model incorporating these biomarkers achieved an area under the curve of 0.891. CONCLUSIONS: A predictive model combining inflammatory and hematologic indicators demonstrated superior predictive accuracy for UT-BSI and may serve as a practical tool for early clinical risk stratification.