1680 - Evaluation of the Urinalysis Reflex to Culture Sensitivity and Impact on Antibiotic Utilization

Background: In June of 2016 at ChristianaCare a urinalysis with reflex to culture (UARC) order set was made available, which allows for urine cultures to be performed automatically if pre-defined criteria for a positive urinalysis are met. The objective of this study was to evaluate the utility of the UARC as it relates to identifying a symptomatic urinary tract infection (UTI), as well as to describe the impact of UARC on antibiotic utilization.

Methods: A retrospective cohort study was performed including patients aged 18 to 89 ordered a UARC. Patients were excluded if they were currently pregnant, had an absolute neutrophil count of < 100 cells/mm³, were undergoing a urological procedure, or receiving antibiotics for another indication. The primary outcome of this study was to determine the utility of the UARC in identifying a symptomatic UTI, as determined by the Youden index. Secondary outcomes evaluated included mean days antibiotics and length of stay, adherence to duration of treatment guidelines, 30 day post discharge readmissions, 30 day post discharge mortality, and new Clostridioides difficile infection within 30 days.

Results: A total of 123 patients were included in this study. A Youden index of 7.2% was calculated for the primary outcome. Patients with a positive UARC and UTI symptoms received an average of 7.54 days of antibiotics. Asymptomatic patients with a positive UARC received significantly more antibiotics than those with a negative UARC (3.05 vs 0 days, respectively ,p=0.02). Adherence to duration of treatment guidelines was found to be 77.8%, 66.7%, and 50% for uncomplicated cystitis, complicated cystitis and pyelonephritis respectively. No difference was observed between groups for length of stay, 30 day post discharge readmissions, and 30 day post discharge mortality. No cases of new C. difficile infection were identified.

Conclusion: This study demonstrates that the UARC does not have utility as a diagnostic test for predicting a symptomatic UTI. The presence of a positive UARC in the absence of symptoms attributable to a UTI resulted in inappropriate prescribing of antibiotics. Further evaluation of how a UARC is ordered, perhaps requiring prescribers to document urinary symptoms, in addition to caregiver education is warranted