An antibiotic stewardship initiative focused on community-acquired bacterial pneumonia (CABP) in outpatient clinics and urgent care centers: a 2023-2024 community health system experience.

Objective: This before-after study aimed to evaluate whether an order-set intervention would improve CABP-guideline concordance among outpatients.

Setting: This study included adult patients presenting to outpatient clinics (n = 92) and urgent care centers (n = 39) within a community-based health system without a formal outpatient antibiotic stewardship program (ASP).

Intervention: The intervention consisted of an antibiotic order-set and awareness campaign. Patient encounters were identified via CABP ICD-10 codes and IDSA-relevant patient comorbidities (chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancy; asplenia) were extracted from the electronic health record. Primary outcome was to describe the proportion of patients receiving concordant therapy per IDSA guideline and local antibiogram in a pre- (May 2023 - April 2024) and post-intervention period (May 2024 - December 2024).

Results: Baseline and intervention antibiotic concordance rate was 33.3% (1,467/4,401 encounters) and 28.0% (1,388/4,954 encounters), respectively. Among patients with no comorbidity, monotherapy prescriptions (concordant and discordant) decreased post-intervention and were replaced by higher levels of combination therapy (15% increase), albeit all discordant due to lack of comorbidities. Among patients with comorbidities, combination antibiotics increased by 12% post-intervention, driven by concordant prescriptions including amoxicillin/clavulanate plus azithromycin while the most frequently prescribed discordant combination was amoxicillin plus azithromycin. Trends were similar in primary care and urgent care centers.

Conclusions: A stewardship intervention, including an order-set and awareness campaign improved the selection of combination therapy for appropriate patients but did not improve overall guideline concordance. For health systems without a dedicated outpatient ASP, these data will help bolster stewardship efforts towards more effective strategies.