Not all pneumonias are created equal

The severity of pneumonia is usually based on the type of infection, the extent of the disease in the lungs and other factors, such as the patient's overall health. Increasingly, however, doctors look closely at how the patient became ill. Research now shows that pneumonias acquired in the community, in hospitals or in other healthcare settings are often very different types of illnesses, and treatment should be tailored accordingly.

A study published in the recent edition of Annals of Internal Medicine elaborates on this idea and suggests that pneumonia should be classified by three subsets: community-acquired, hospital-acquired and healthcare-acquired. Many doctors distinguish between hospital- and community-acquired pneumonias already. But the new study shows that healthcare-associated disease is different and much more severe than community-acquired disease. Healthcare-acquired pneumonia typically includes patients who have had recent contact with the healthcare system through nursing homes, hemodialysis clinics or recent hospitalizations.

Researchers from the University of Rome and Universita degli Studi di Palermo examined 362 patients with pneumonia admitted to hospitals throughout Italy during a one-week period. They found that patients with healthcare-acquired and hospital-acquired pneumonia were much sicker than people with community-acquired pneumonia. Death rates were 18.4% for hospital-acquired, 17.8% for healthcare-acquired and 6.7% for community-acquired. People with healthcare-acquired cases were also hospitalized an average of four days longer than people with community-acquired. The three groups of patients did not differ significantly in their average age or the presence of other health problems that could complicate their recovery. People with hospital-acquired pneumonia, however, were the most critically ill.

How the disease begins is important to note, said the authors of the study, because treatment, such as the selection of an antibiotic, can vary according to that information. The study found that 5.8% of the patients with community-acquired pneumonia received inappropriate antibiotic therapy compared with 18.9% of people with healthcare-acquired pneumonia.

"Physicians usually do not differentiate between the initial treatment for health care-associated pneumonia and community-acquired pneumonia, and this clinical approach usually results in inappropriate initial therapy and increased mortality," the authors wrote.

Annals of Internal Medicine website has a patient page describing the study.

-- Shari Roan

Photo: Staphylococcus aureus bacteria, which can cause pneumonia. Credit: Centers for Disease Control and Prevention