Excess Antibiotic Treatment Duration and Adverse Events in Patients Hospitalized With Pneumonia: A Multihospital Cohort Study.

Background: Randomized trials demonstrate no benefit from antibiotic treatment exceeding the shortest effective duration. Objective: To examine predictors and outcomes associated with excess duration of antibiotic treatment. Design: Retrospective cohort study. Setting: 43 hospitals in the Michigan Hospital Medicine Safety Consortium. Patients: 6481 general care medical patients with pneumonia. Measurements: The primary outcome was the rate of excess antibiotic treatment duration (excess days per 30-day period). Excess days were calculated by subtracting each patient's shortest effective (expected) treatment duration (based on time to clinical stability, pathogen, and pneumonia classification [community-acquired vs. health care-associated]) from the actual duration. Negative binomial generalized estimating equations (GEEs) were used to calculate rate ratios to assess predictors of 30-day rates of excess duration. Patient outcomes, assessed at 30 days via the medical record and telephone calls, were evaluated using logit GEEs that adjusted for patient characteristics and probability of treatment. Results: Two thirds (67.8% [4391 of 6481]) of patients received excess antibiotic therapy. Antibiotics prescribed at discharge accounted for 93.2% of excess duration. Patients who had respiratory cultures or nonculture diagnostic testing, had a longer stay, received a high-risk antibiotic in the prior 90 days, had community-acquired pneumonia, or did not have a total antibiotic treatment duration documented at discharge were more likely to receive excess treatment. Excess treatment was not associated with lower rates of any adverse outcomes, including death, readmission, emergency department visit, or Clostridioides difficile infection. Each excess day of treatment was associated with a 5% increase in the odds of antibiotic-associated adverse events reported by patients after discharge. Limitation: Retrospective design; not all patients could be contacted to report 30-day outcomes. Conclusion: Patients hospitalized with pneumonia often receive excess antibiotic therapy. Excess antibiotic treatment was associated with patient-reported adverse events. Future interventions should focus on whether reducing excess treatment and improving documentation at discharge improves outcomes. Primary Funding Source: Blue Cross Blue Shield of Michigan (BCBSM) and Blue Care Network as part of the BCBSM Value Partnerships program.