Importance: Antibiotic therapy is the cornerstone of medical management for community-acquired pneumonia.
Objective: To assess the associations between 3 key aspects of antibiotic therapy (optimal time to antibiotic initiation, initial antibiotic selection, and criteria for the transition from intravenous to oral therapy) and short-term mortality in adults hospitalized with community-acquired pneumonia.
Evidence review: Bibliographic databases of MEDLINE, EMBASE, and the Cochrane Collaboration were searched for studies of adults hospitalized with radiographically confirmed community-acquired pneumonia published from January 1, 1995, until November 5, 2015.
Findings: Twenty studies (17 observational and 3 randomized trials) met eligibility criteria. Among 8 observational studies identified, the 4 largest (study populations of 2878 to 1,170,022) found that antibiotic initiation within 4 to 8 hours of hospital arrival was associated with relative reductions of 5% to 43% in mortality; the 4 smallest studies (study populations of 451 to 2076) found no associations between the timing of antibiotic initiation and mortality. One cluster randomized trial (n = 1737) demonstrated noninferiority of β-lactam monotherapy (n = 506) vs β-lactam plus macrolide combination therapy (n = 566), with an absolute adjusted difference of 2.5% (90% CI, -0.6% to 5.2%) in 90-day mortality favoring β-lactam monotherapy. A second randomized trial (n = 580) failed to demonstrate noninferiority of β-lactam monotherapy vs β-lactam plus macrolide combination therapy, with an absolute difference of 7.6% (1-sided 90% CI upper limit, 13.0%) in attainment of clinical stability on hospital day 7 favoring β-lactam plus macrolide combination therapy. Six of 8 observational studies (study populations of 1188 to 24,780) found that β-lactam plus macrolide combination therapy was associated with relative reductions of 26% to 68% in short-term mortality and all 3 observational studies (study populations of 2068 to 24,780) reported that fluoroquinolone monotherapy was associated with relative reductions of 30% to 43% in mortality compared with β-lactam monotherapy. One randomized trial (n = 302) reported significantly reduced hospital length of stay (absolute difference, 1.9 days; 95% CI, 0.6 to 3.2 days), but no differences in treatment failure when objective clinical criteria were used to decide when to transition patients from intravenous to oral therapy.
Conclusions and relevance: In adults hospitalized with community-acquired pneumonia, antibiotic therapy consisting of β-lactam plus macrolide combination therapy or fluoroquinolone monotherapy initiated within 4 to 8 hours of hospital arrival was associated with lower adjusted short-term mortality, supported predominantly by low-quality observational studies. One randomized trial supports the use of objective clinical criteria to guide the transition from intravenous to oral antibiotic therapy.