Analysis of an Antibiotic Stewardship Program for Asymptomatic Bacteriuria in the Veterans Affairs Health Care System

Abstract

Antibiotic stewardship for asymptomatic bacteriuria (ASB) is an important quality improvement target. Understanding how to implement successful antibiotic stewardship interventions is limited. To evaluate the effectiveness of a quality improvement stewardship intervention on reducing unnecessary urine cultures and antibiotic use in patients with ASB. This interrupted time series quality improvement study was performed at the acute inpatient medical and long-term care units of 4 intervention sites and 4 comparison sites in the Veterans Affairs (VA) health care system from October 1, 2017, through April 30, 2020. Participants included the clinicians who order or collect urine cultures and who order, dispense, or administer antibiotics. Clinical outcomes were measured in all patients in a study unit during the study period. Data were analyzed from July 6, 2020, to May 24, 2021. Case-based teaching on how to apply an evidence-based algorithm to distinguish urinary tract infection and ASB. The intervention was implemented through external facilitation by a centralized coordinating center, with a site champion at each intervention site serving as an internal facilitator. Urine culture orders and days of antibiotic therapy (DOT) and length of antibiotic therapy in days (LOT) associated with urine cultures, standardized by 1000 bed-days, were obtained from the VA's Corporate Data Warehouse. Of 11 299 patients included, 10 703 (94.7%) were men, with a mean (SD) age of 72.6 (11.8) years. The decrease in urine cultures before and after the intervention was not significant in intervention sites per segmented regression analysis (-0.04 [95% CI, -0.17 to 0.09]; P = .56). However, difference-in-differences analysis comparing intervention with comparison sites found a significant reduction in the number of urine cultures ordered by 3.24 urine cultures per 1000 bed-days (P = .003). In the segmented regression analyses, the relative percentage decrease of DOT in the postintervention period at the intervention sites was 21.7% (P = .007), from 46.1 (95% CI, 28.8-63.4) to 37.0 (95% CI, 22.6-51.4) per 1000 bed-days. The relative percentage decrease of LOT in the postintervention period at the intervention sites was 21.0% (P = .001), from 36.7 (95% CI, 23.2-50.2) to 29.6 (95% CI, 18.2-41.0) per 1000 bed-days. The findings of this quality improvement study suggest that an individualized intervention for antibiotic stewardship for ASB was associated with a decrease in urine cultures and antibiotic use when implemented at multiple sites via external and internal facilitation. The electronic health record database-derived outcome measures and centralized facilitation approach are both suitable for dissemination.