Background: Studies that have assessed antibiotic appropriateness in acute respiratory tract infections (RTIs) with a likely bacterial etiology have focused only on antibiotic choice and ignored other important aspects of prescribing, such as dosing, drug-drug interactions, and duration of treatment.
Objective: The aim of this study was to determine the prevalence and predictors of inappropriate antibiotic prescribing practices in outpatients with acute bacterial RTIs (community-acquired pneumonia [CAP], sinusitis, or acute exacerbations of chronic bronchitis [AECB]).
Methods: This retrospective, cross-sectional study enrolled outpatients with CAP, sinusitis, or AECB who were evaluated in a Veterans Affairs emergency department over a 1-year period. Using electronic medical records, trained research assistants completed data-collection forms that included patient characteristics (eg, marital status, history of alcohol abuse), diagnosis, comorbidities, concurrent medications, and antibiotics prescribed. To assess antimicrobial appropriateness, a trained clinical pharmacist reviewed the data-collection forms and applied a Medication Appropriateness Index (MAI), which rated the appropriateness of a medication using 10 criteria: indication, effectiveness, dosage, directions, practicality (defined as capability of being used or being put into practice), drug-drug interactions, drug-disease interactions, unnecessary duplication, duration, and expensiveness (defined as the cost of the drug compared with other agents of similar efficacy and tolerability). Previous studies have found good inter- and intrarater reliabilities between a clinical pharmacist's and an internal medicine physician's MAI ratings (kappa=0.83 and 0.92, respectively).
Results: One hundred fifty-three patients were included (mean age, 58 years; 92% male; and 65% white). Overall, 99 of 153 patients (65%) had inappropriate antibiotic prescribing as assessed using the MAI. Expensiveness (60 patients [39%]), impracticality (32 [21%]), and incorrect dosage (15 [10%]) were the most frequently rated problem. Penicillins, quinolones, and macrolides were the most common antibiotic classes prescribed inappropriately. A history of alcohol abuse was associated with a lower likelihood of inappropriate prescribing compared with no history of alcohol abuse (adjusted odds ratio [AOR], 0.32; 95% CI, 0.10-0.98), while patients who were married were more likely to receive inappropriately prescribed antibiotics than those who were not married (AOR, 2.64; 95% CI, 1.25-5.59).
Conclusions: Inappropriate antibiotic prescribing based on the MAI criteria was common (65%) in this selected patient population with acute bacterial RTIs, and often involved problems with expensiveness (39%), impracticality (21%), and incorrect dosage (10%). Future interventions to improve antibiotic prescribing should consider aspects beyond choice of agent.