Claims-Based Identification of Urinary Tract Infections among Patients in Long-Term Care Wards: A Retrospective Validation Study

Claims data can be a resource for epidemiological evaluations in long-term care patients at increased risk of urinary tract infections (UTI) from antimicrobial-resistant bacteria. However, as claims data are primarily collected for administrative purposes, validating diagnostic accuracy is required. This study evaluated the validity of claims-based UTI identification in this patient population. This retrospective study included patients in long-term care wards between January 2023 and December 2024. Using diagnoses from electronic medical records as the gold standard, we evaluated the positive predictive value (PPV) of claims-based identification of UTI and catheter-associated UTI (CAUTI). Diagnoses were identified using International Classification of Diseases, 10th Revision (ICD-10) codes or urinalysis with microscopy, urine culture, antibiotic prescriptions, or indwelling bladder catheter procedures. Sensitivity analysis excluding suspected diagnoses was performed. Among 523 patients, 200 with at least one ICD-10 code for UTI were randomly selected. The PPV for identifying UTI using ICD-10 codes improved from 66.0 to 77.8% when additional codes were combined, and that for CAUTI improved from 45.5 to 86.8% with indwelling bladder catheter procedures. Excluding suspected diagnoses further improved the accuracy. Integrating ICD-10 codes, urinalysis with microscopy, urine culture, antibiotic prescriptions, and, when relevant, indwelling bladder catheter procedures while excluding suspected diagnoses enhances the validity of claims-based UTI identification and may be applicable to database studies using claims data.