BackgroundThe use of antibiotics in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with clear evidence of pneumonia is considered standard practice. However, without radiographic bacterial pneumonia, the net impact of antibiotics is equivocal.ObjectiveTo study physician-level practice variation in antibiotic prescribing and associated outcomes for patients hospitalized with AECOPD without pneumonia.DesignRetrospective cohort study.ParticipantsPatients admitted to general internal medicine wards across seven hospitals in Ontario, Canada, between April 2010 and December 2020 with AECOPD without pneumonia. Each hospitalization was attributed to the admitting physician.ExposureTo avoid indication bias (sicker patients are more likely to receive antibiotics), the main exposure was the propensity of a patient’s physician to prescribe antibiotics in AECOPD, measured by the proportion of their AECOPD patients treated with antibiotics.Main measuresWe studied four outcomes using multivariable regression to adjust for patient baseline characteristics: in-patient mortality, intensive care unit (ICU) transfer, 30-day hospital readmission, and hospital length of stay (LOS).Key resultsThe cohort included 2043 hospitalizations cared for by 106 physicians. Overall, 52.1% of patients were treated with antibiotics. Physician antibiotic prescribing ranged from 15.2 to 96.2% (median 69.2%, IQR 50.9 to 76.5). Physician propensity to prescribe antibiotics was not significantly associated with patient-level clinical outcomes, including in-patient mortality (adjusted odds ratio [aOR] 1.05, 95% confidence intervals [CI] = 1.00 to 1.10), ICU transfer (aOR 1.04, 95%CI = 1.00 to 1.09), 30-day readmission (aOR 1.01, 95%CI = 0.99 to 1.02), and hospital LOS (adjusted risk ratio 1.00, 95%CI = 0.99 to 1.00) (all not statistically significant).ConclusionsMore than half of patients hospitalized to a medical ward with AECOPD without pneumonia were treated with antibiotics. Antibiotic prescribing varied widely across physicians, and greater prescribing was not associated with better outcomes.