Background: Antimicrobial stewardship (AMS) interventions have predominantly involved inpatient antimicrobial therapy. However, for many hospitalized patients, most antibiotic use occurs after discharge, and unnecessarily prolonged courses of therapy are common. Patient transition from hospitalization to discharge represents an important opportunity for AMS intervention. We describe patterns of antibiotic use selection and duration of therapy (DOT) for common infections including discharge antibiotics. Methods: This retrospective cross-sectional analysis was derived from an IRB-approved, multihospital, quasi-experiment at a 5-hospital health system in southeastern Michigan. The study population included patients discharged from an inpatient general and specialty practice ward on oral antibiotics from November 2018 through April 2019. Patients were included with the following diagnoses: skin and soft-tissue infections (SSTIs), community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), respiratory viral infections, acute exacerbation of chronic obstructive pulmonary disease (AECOPD), intra-abdominal infections (IAIs), and urinary tract infections (UTIs). Other diagnoses were excluded. Data were extracted from medical records including antibiotic indication, selection, and duration, as well as patient characteristics. Results: In total, 1,574 patients were screened and 800 patients were eligible for inclusion. The most common antibiotic indications were respiratory tract infections, with 487 (60.9%) patients. These included 165 AECOPD cases (20.6%) and 200 CAP cases (25%) with no multidrug resistant organism (MDRO) risk factors; 57 patients (7.1%) with MDRO risk factors; HAP in 7 patients (0.9%); and influenza in 58 patients (7.2%). Also, 205 (25.6%) patients were diagnosed with UTIs: 71 with cystitis (8.9%), 86 (10.8%) with complicated UTI (cUTI), and 48 (6%) with pyelonephritis. Furthermore, 125 patients (15.6%) were diagnosed with SSTI: 59 (7.4%) purulent and 66 (8.3%) nonpurulent. 31 (3.9%) patients had an IAI. The most commonly used antibiotics were cephalosporins in 536 patients (67%), azithromycin in 252 patients (31.5%), and fluroquinolones and tetracyclines in 231 patients (28.9%). Fluroquinolones were the most frequent antibiotic prescribed at discharge in 210 patients (26.3%). Figure 1 displays the average DOT relative to specific indications. The median duration of total antibiotic therapy exceeded institutional guideline recommendation for multiple conditions, including AECOPD (7 days vs recommended 5 days), CAP with COPD (8.3 vs 7 days ), CAP without COPD (7.7 vs 5 days), and pyelonephritis (11 vs 7–10 days). Also, 269 (33.6%) patients received unnecessary therapy; 218 (27.3%) of these were due to excess duration. Conclusions: Among a cross-section of hospitalized patients, the average DOT, including after discharge, exceeded the optimal therapy for many patients. Further understanding of patterns and influences of antibiotic prescribing is necessary to design effective AMS interventions for improvement.
Funding: This work was completed under CDC contract number 200-2018-02928.