Study Highlights Need for Improved Diagnostic Tests to Identify Pneumonia

Viruses, not bacteria, are the most commonly detected pathogen in US adults hospitalized with pneumonia; however, neither viruses nor bacteria are detected in the majority of these patients despite current diagnostic tests, according to study conducted by the CDC.

The researchers enrolled 2488 adults hospitalized with community-acquired pneumonia at hospitals in Chicago and Nashville and discovered a need for more sensitive rapid diagnostic tests to identify pneumonia.

During the 2-and-a-half year study, known as the CDC Etiology of Pneumonia in the Community (EPIC) study, neither viruses nor bacteria were detected in 62% of participants. The results of the study were published in the New England Journal of Medicine.

“Pneumonia is a leading cause of hospitalization and death among adults in the United States and in 2011 the medical costs exceeded $10 billion,” CDC Director Tom Frieden, MD, MPH, said in a statement. “Most of the time doctors are unable to pinpoint a specific cause of pneumonia. We urgently need more sensitive, rapid tests to identify causes of pneumonia and to promote better treatment.”

Viruses were detected in 27% of patients and bacteria in 14% of patients, according to the study. Among pneumonia patients, the human rhinovirus was the most commonly detected virus, followed by influenza.

According to Seema Jain, MD, lead author of the paper and medical epidemiologist in CDC’s Influenza Division, the frequency with which respiratory viruses were detected in hospitalized patients with pneumonia was higher than previously documented, which may be a result of improved diagnostics.

“However, what’s most remarkable is that despite how hard we looked for pathogens, no discernible pathogen was detected in 62% of adults hospitalized with pneumonia in the EPIC study,” Dr Jain said. “This illustrates the need for more sensitive diagnostic methods that can both help guide treatment at the individual level as well as inform public health policy for adult pneumonia at a population level.”