Older Adults More Likely to Have Inappropriately Diagnosed Community-Acquired Pneumonia


These data may have impactful clinical and health policy implications, given that hospitalizations for CAP are known to be common and given the frequency of incorrect diagnoses.

Ashwin B. Gupta, MD

Credit: X (Twitter)

Ashwin B. Gupta, MD

Credit: X (Twitter)

Individuals with dementia, those presenting altered mental status, and older adults in general were all more likely to have experienced inappropriate diagnosis of community-acquired pneumonia (CAP) among adults who have been hospitalized, according to new findings, and full-course antibiotic treatment may harm such individuals.1

These results were the conclusion of a new cohort study of 17,290 individuals who had been hospitalized for pneumonia in a set of hospitals in Michigan. This research was led by Ashwin B. Gupta, MD, from the Medicine Service at the VA Ann Arbor Healthcare System in Michigan.

Gupta and colleagues noted the ever-present challenge of correctly quantifying the proportion of those given CAP treatment who have been inappropriately diagnosed. They connected this to an overall lack of validated definitions.

“In 2022, we devised a metric to quantify inappropriate diagnosis of CAP that was validated and subsequently endorsed by the National Quality Forum (NQF),” Gupta and colleagues wrote. “Herein, we apply this metric to a cohort of hospitalized patients treated for CAP in 48 Michigan hospitals to understand epidemiology and outcomes associated with inappropriate CAP diagnosis.”2,3

Study Background and Methods

The collaborative initiative known as the Michigan Hospital Medicine Safety Consortium (HMS) had been designed with the goal of enhancing hospitalized patient care. The investigators noted that by January 2023, 75% of the 92 noncritical access, nonfederal hospitals in the state of Michigan were part of HMS, with shared data available on implementation of antibiotics.

The team’s research involved 48 hospitals throughout the study period, during which they had abstractors retrospectively assess adult patients that had been given treatment for pneumonia from July 2017 - March 2020. Criteria for inclusion in the study included being an adult admitted to general care, having a pneumonia diagnosis, and having a course of antibiotics begun on day 1 or 2 of one’s hospitalization.

Exclusion criteria involved being severely immunocompromised, having additional unrelated infections documented, being pregnant, having been admitted for palliative care, or being a patient who left against clinician advice. The team’s prospective cohort study looked at the prior from February - December 2023, highlighting incorrectly-diagnosed CAP using established criteria.

The investigators evaluated risk factors for possible misdiagnosis. Research outcomes were stratified by the research team based upon duration of antibiotic use (>3 days compared to ≤3 days), considering readmission, mortality, interactions with emergency departments, Clostridioides difficile infection, and antibiotic-related adverse events (AEs).


Overall, among the 17,290 individuals given admission due to CAP, there had been 12.0% who were identified by the research team as having received an incorrect diagnosis. There was a median age of 71.8 years, and 50.3% of the subjects were reported to be female.

The team reported that 87.6% of these subjects had been given a complete course of antibiotics. In their comparison of those diagnosed correctly, the investigators found that patients with inappropriate CAP diagnoses tended to be labeled as older (adjusted odds ratio [AOR] per decade, 1.08; 95% CI, 1.05-1.11) and shown to be more likely to have conditions such as altered mental status at CAP presentation (AOR, 1.75; 95% CI, 1.39-2.19) or dementia (AOR, 1.79; 95% CI, 1.55-2.08).

The research team found no major distinction among those given an inappropriate diagnosis in the team’s 30-day composite outcomes between those given full antibiotics versus a more brief treatment (25.8% versus 25.6%; AOR, 0.98; 95% CI, 0.79-1.23). Despite these findings, the investigators showed that a full-duration course of antibiotics among these subjects was connected to having higher incidence of antibiotic-associated AEs versus more brief treatments (2.1% versus 0.4%; P = .03).

“These same vulnerable populations are also most likely to be affected by antibiotic-associated adverse events and resulting morbidity,” they wrote. “Thus, balancing harms of underdiagnosis and overdiagnosis of CAP remains essential.”


  1. Gupta AB, Flanders SA, Petty LA, et al. Inappropriate Diagnosis of Pneumonia Among Hospitalized Adults. JAMA Intern Med. Published online March 25, 2024. doi:10.1001/jamainternmed.2024.0077.
  2. Inappropriate diagnosis of community-acquired pneumonia (CAP) in hospitalized medical patients. Partnership for Quality Measurement. December 12, 2022. Accessed July 14, 2023. https://p4qm.org/measures/3671.
  3. Inappropriate diagnosis of community-acquired pneumonia (CAP) in hospitalized medical patients. Michigan Hospital Medicine Safety Consortium. Accessed February 19, 2024. https://mi-hms.org/inappropriate-diagnosis-community-acquired-pneumonia-cap-hospitalized-medical-patients.
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