Inappropriate diagnosis of community-acquired pneumonia (CAP) among hospitalized adults is common, says a new study published March 25, 2024 in JAMA Internal Medicine.¹ Typically, older patients, those suffering from dementia and those exhibiting altered mental status at presentation were more likely to receive an incorrect diagnosis.

This prospective cohort study was conducted in 48 Michigan hospitals and involved retrospective analysis of phone calls and medical records of patients hospitalized for CAP between July 2017 and March 2020. Adult patients hospitalized to general care with a discharge diagnostic code of pneumonia who were prescribed antibiotics on the first or second day of hospitalization qualified for inclusion in the study. The objective of the study was characterization of inappropriate diagnosis of CAP in hospitalized patients.

“CAP-directed antibiotic therapy in patients with fewer than two signs or symptoms of CAP or negative chest imaging” was the criteria used to define inappropriate diagnosis of CAP. The 30-day composite outcomes (mortality, readmission, ED visit, Clostridium difficile infection, and antibiotic-associated adverse events) were recorded in the group of inappropriately diagnosed patients and they were further categorized on the basis of antibiotic treatment duration: full course (>3 days) vs brief (≤3 days).

Analysis of data of 17,290 patients revealed that 2079 (12.0%) patients, median age 71.8 years, had been diagnosed with CAP incorrectly. Half (50.3%) of them were female and 1821 (87.6%) had been treated with a  full course of antibiotics. Patients who received an incorrect diagnosis were older in age with adjusted odds ratio (aOR) of 1.08. They also had higher risks of having dementia (aOR 1.79) or altered mental status at presentation (aOR 1.75) than patients with CAP. The 30-day composite outcomes for full versus brief therapy did not differ among those who were misdiagnosed (25.8% vs. 25.6%; AOR, 0.98). Antibiotic-associated adverse events were correlated with patients receiving antibiotics for the full vs brief course of treatment (2.1% vs 0.4%).

This study has identified certain groups of hospitalized patients at higher risk for inappropriate diagnosis of CAP. Full-course antibiotic treatment of these patients could have negative consequences without therapeutic benefits. The unnecessary antibiotic exposure may potentially cause adverse effects and contribute to development of antibiotic resistance and increase healthcare costs. While these findings emphasize the need for accurate diagnosis, they also underscore the importance of judicious use of antibiotics to reduce morbidity.

Reference

1. Ashwin B Gupta, et al. Inappropriate diagnosis of pneumonia among hospitalized adults. JAMA Intern Med. 2024 Mar 25:e240077. doi: 10.1001/jamainternmed.2024.0077.