Comparison of outcomes for low-risk outpatients and inpatients with pneumonia: A propensity-adjusted analysis.

Abstract

Low-risk patients with community-acquired pneumonia are often hospitalized despite guideline recommendations for outpatient treatment. Using data from a randomized trial conducted in 32 emergency departments, we performed a propensity-adjusted analysis to compare 30-day mortality rates, time to the return to work and to usual activities, and patient satisfaction with care between 944 outpatients and 549 inpatients in pneumonia severity index risk classes I to III who did not have evidence of arterial oxygen desaturation, or medical or psychosocial contraindications to outpatient treatment. After adjusting for quintile of propensity score for outpatient treatment, which eliminated all significant differences for baseline characteristics, outpatients were more likely to return to work (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.5 to 2.6) or, for nonworkers, to usual activities (OR, 1.4; 95% CI, 1.1 to 1.8) than were inpatients. Satisfaction with the site-of-treatment decision (OR, 1.1; 95% CI, 0.7 to 1.8), with emergency department care (OR, 1.4; 95% CI, 0.9 to 1.9), and with overall medical care (OR, 1.1; 95% CI, 0.8 to 1.6) was not different between outpatients and inpatients. The overall mortality rate was higher for inpatients than outpatients (2.6% vs 0.1%, respectively; p < 0.01); the mortality rate was not different among the 242 outpatients and 242 inpatients matched by their propensity score (0.4% vs 0.8%, respectively; p = 0.99). After adjusting for the propensity of site of treatment, outpatient treatment was associated with a more rapid return to usual activities and to work, and with no increased risk of mortality. The higher observed mortality rate among all low-risk inpatients suggests that physician judgment is an important complement to objective risk stratification in the site-of-treatment decision for patients with pneumonia.