Purpose

To identify a low-risk subset of patients with community-acquired pneumonia that could safely be treated in the ambulatory setting; and to assess how clinicians make the hospitalization decision.

Patients and methods

We performed a prospective, observational study of 280 ambulatory and hospitalized adults with clinical and radiographic evidence of pneumonia. Patients were followed to assess all potential morbid complications and 6-week mortality. Physicians responsible for managing these patients were surveyed to assess the reasons for treating in a hospital or ambulatory setting and the therapies that dictate hospitalization.

Results

Sixty-one percent (170 of 280) of patients did not have an indication for admission at presentation using modified Appropriateness Evaluation Protocol criteria (a severe vital sign abnormality, alteration in mental status, suppurative complication, arterial hypoxemia, severe laboratory abnormality, or an acute coexistent medical problem requiring admission independent of the pneumonia). Among these 170 patients, 38% had a complicated course defined as death within 6 weeks, development of a new suppurative or medical complication due to pneumonia, intensive care unit admission, persistent fever or use of intravenous fluids or oxygen beyond 3 days, hospitalization lasting more than 3 days, or subsequent hospitalization in patients initially treated in the ambulatory setting. Five predisposing factors for a complicated course were identified in logistic regression models. The odds ratio for age more than 65 years was 2.7; for comorbid illness, 3.2; for temperature more than 38.3 degrees C (101 degrees F), 4.1; for immunosuppression, 12.0; and for a high-risk etiology, 23.3. The risk of a complicated course increased linearly with the number of risk factors, from 12% with none to 100% with four or more factors (p less than 0.001). Physicians most often relied on the general clinical appearance of the patient when making the triage decision, and most commonly cited intravenous antibiotics and chest physical therapy as treatments requiring hospitalization.

Conclusions

If validated, our findings could improve physicians' assessment of prognosis, and may identify a low-risk subset of patients with community-acquired pneumonia who could safely be managed in the ambulatory setting.