Most patients with misdiagnosed pneumonia are given full courses of antibiotics with potential for harm.

Hospitalised patients with misdiagnosed community-acquired pneumonia (CAP) are often treated inappropriately with antibiotics. This process can delay correct treatment of alternative conditions, cause antibiotic-associated adverse events and antibiotic resistance, and increase costs.

In this prospective cohort study of 17,000 patients in 48 Michigan hospitals whose discharge diagnoses included CAP, 12% of patients had inappropriate diagnoses (i.e. fewer than two signs/symptoms of CAP or negative chest imaging). Nearly 90% of patients with misdiagnosed CAP received full courses of antibiotics (more than three days). Inappropriate diagnosis of CAP was more likely in older patients (particularly those older than 75 years) and those with dementia or altered mental status.

Among patients who were treated inappropriately for CAP, antibiotic-associated adverse events were significantly more common with full-course antibiotics than with courses of fewer than three days (number needed to harm, 59). However, no significant associations were noted between duration of antibiotic therapy and 30-day incidence of death, readmission, emergency department visits or Clostridioides difficile infections in this inappropriately treated group. 

Comment: Older patients are the ones most likely to be inappropriately treated empirically for CAP but are also the ones most likely to decompensate if a diagnosis of CAP is missed. Clinicians should feel comfortable initiating antibiotics empirically in vulnerable patients with presumed CAP but should discontinue antibiotics within 48 to 72 hours if a different diagnosis becomes apparent.

Aaron J. Calderon, MD, FACP, SFHM, Program Director, Internal Medicine Residency, Saint Joseph Hospital; Clinical Professor of Medicine, Division of General Internal Medicine, University of Colorado School of Medicine, Denver, USA.

Gupta AB, et al. Inappropriate diagnosis of pneumonia among hospitalized adults. JAMA Intern Med 2024; 184: 548-556.

This summary is taken from the following Journal Watch titles: General Medicine, Hospital Medicine.