A Propensity Score Matched Study of the Positive Impact of Infectious Diseases Consultation on Antimicrobial Appropriateness in Hospitalized Patients with Antimicrobial Stewardship Oversight

Hospital-based antibiotic stewardship (AS) programs provide oversight and guidance for appropriate antimicrobial use in acute care settings. Infectious disease expertise is beneficial in the care of hospitalized patients with infections. The impact of infectious diseases consultation (IDC) on antimicrobial appropriateness in a large tertiary hospital with an established AS program was investigated. This was a cross-sectional study from October 2017 to March 2019 at a large academic hospital with an AS-directed prospective audit and feedback process and multiple IDC services. Antimicrobial appropriateness was adjudicated by an AS team member after antimicrobial start. Antimicrobial appropriateness was compared among antimicrobial orders with and without IDC using propensity score matching and multivariable logistic regression. Analyses were stratified by primary services caring for the patients. There were 10,508 antimicrobial orders from 6,165 unique patient encounters. Overall appropriateness was 92%, with higher appropriateness among patients with IDC versus without IDC (94% versus 84%; P < 0.0001). After propensity score matching and adjustment for certain antibiotics, organisms, syndromes, and locations, IDC was associated with a greater antimicrobial appropriateness odds ratio (OR) of 2.4 (95% confidence interval [CI], 1.9 to 3.0). Stratification by primary service showed an OR of 2.9 (95% CI, 2.1 to 3.8) for surgical specialties and an OR of 1.6 (95% CI, 1.1 to 2.2) for medical specialties. Even with a high overall antimicrobial appropriateness, patients with IDC had greater odds of antimicrobial appropriateness than those without IDC, and this impact was greater in surgical specialties. Infectious diseases consultation can be synergistic with antimicrobial stewardship programs.