Tight adherence to guidelines for managing people who catch pneumonia in the community - such as starting antibiotics within 4 hours of arrival at the hospital - raises the risk of misdiagnosis and inappropriate use of antibiotics, doctors in Detroit have found.

Based on their research, Dr. Mohamad G. Fakih and associates at St. John Hospital and Medical Center advocate a 6-hour window between arrival at the emergency department and administration of antibiotics as a more feasible target.

“This target may provide more time for physicians to provide a better evaluation of the patient,” Fakih and colleagues write in the journal Chest.

They looked at outcomes of patients admitted to the ED with a diagnosis of community-acquired pneumonia during 6-month periods prior to and after publication of the guidelines. There were 199 patients treated between January and June, 2003, and 319 patients treated between January and June, 2005.

Since publication of the guidelines, “we have seen almost a 60 percent increase in the hospital admitting diagnosis of community-acquired pneumonia compared to a less than 25 percent increase in the hospital discharge diagnosis of community-acquired pneumonia,” the researchers note.

Results showed that the goal of starting antibiotic treatment within 4 hours increased from 54 percent before the guidelines were published to 66 percent after publication.

However, more patients in 2005 (after publication) had a diagnosis of community-acquired pneumonia without radiographic evidence of abnormalities (28.5 percent versus 20.6 percent), suggesting an incorrect diagnosis.

Of those misdiagnosed, only a minority were diagnosed with any type of infection, implying that they were treated unnecessarily with antibiotics.

Fakih’s group also failed to see any significant improvement over time in average hospital length of stay or in-hospital mortality following publication of the guidelines.

They conclude based on their observations that a 6-hour time frame is perhaps more appropriate than a 4-hour time frame for people arriving at the hospital with suspected pneumonia.

SOURCE: Chest, June 2007.