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

Chest. 2007 Feb;131(2):480-8. doi: 10.1378/chest.06-1393.


Background: Low-risk patients with community-acquired pneumonia are often hospitalized despite guideline recommendations for outpatient treatment.

Methods: 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.

Results: 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).

Conclusions: 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.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Ambulatory Care*
  • Female
  • Hospitalization*
  • Humans
  • Male
  • Middle Aged
  • Patient Satisfaction
  • Pneumonia / mortality
  • Pneumonia / therapy*
  • Recovery of Function
  • Retrospective Studies
  • Risk Assessment
  • Severity of Illness Index
  • Survival Rate
  • Treatment Outcome