Key Point

Despite recommendations to the contrary, many persons with community-acquired pneumonia who have low severity index scores are admitted to the hospital instead of treated on an outpatient basis.

PITTSBURGH—Medical specialty organizations such as the Infectious Diseases Society of America recommend that persons with community-acquired pneumonia who have low severity index scores be treated as outpatients. Yet in studies involving low-risk patients, as many as 31% to 62% were admitted to a hospital. To determine the differences in outcomes for low-risk patients treated as inpatients or as outpatients, Labarere et al, reporting in Chest, analyzed data from a randomized trial conducted in 32 emergency departments.

For inclusion in the analysis, the investigators identified data for 1,493 low-risk patients with no contraindications to outpatient treatment; 549 (37%) were treated as inpatients. (Patients in pneumonia severity index [PSI] risk classes I to III who did not have evidence of arterial oxygen desaturation at baseline were considered low risk.) Patients’ median age was 51; 47% of patients were male, 17% were nonwhite, and 11% were uninsured.

Compared with inpatients, outpatients were younger, less likely to be in risk classes II or III or to have comorbid conditions, and more likely to be nonwhite, to have Medicaid or no health insurance, and to present to the emergency department at night or on a weekend. Although 70% of low-risk inpatients had preexisting treatments, radiographic abnormalities, or comorbid conditions, “the remaining 30% had no identifiable risk factors for hospitalization other than those that determine PSI risk class,” the authors noted.

Overall mortality was 0.1% and 2.6% for low-risk outpatients and inpatients, respectively; however, after adjustment for potential confounders of site treatment, there were no between-group differences in mortality. Furthermore, outpatients were nearly twice as likely as inpatients to return to work or to usual activities within 30 days. “The differences in median time to return to work and usual activities between outpatients and inpatients ranged from six to nine days and were not explained by the length of stay among low-risk inpatients,” the researchers said.

Unadjusted calculations suggested a higher mortality rate among inpatients than outpatients. “This finding indicates that even within a homogeneous population of low-risk patients, physicians are capable of discerning subtle differences in illness severity and use such clinical judgments to guide the selection of the initial site of treatment,” the authors concluded.           

—Adriene Marshall

Suggested Reading
Labarere J, Stone RA, Obrosky DS, et al. Comparison of outcomes for low-risk outpatients and inpatients with pneumonia: a propensity-adjusted analysis. Chest. 2007;
131:480-488.

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