title: Comparison of two guideline-concordant antimicrobial combinations in elderly patients hospitalized with severe community-acquired pneumonia.
abstract: OBJECTIVE
  Two of the guideline-concordant therapies for severe community-acquired pneumonia are either a beta-lactam and fluoroquinolone or beta-lactam and macrolide. However it is unclear if there is a benefit for one vs. the other for elderly patients with severe community-acquired pneumonia.
  
  
  METHODS
  A retrospective population-based cohort study of patients with community-acquired pneumonia.
  
  
  METHODS
  Patients admitted to an intensive care unit of any Department of Veterans Affairs hospital during 5-yr period.
  
  
  METHODS
  We included only those patients>65 yrs of age admitted to the intensive care unit with community-acquired pneumonia who received either beta-lactam+fluoroquinolone or beta-lactam+macrolide antibiotic therapy for pneumonia.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  We used multilevel regression models to examine the effect of beta-lactam+fluoroquinolone vs. beta-lactam+macrolide on each of the outcomes after adjusting for potential confounders using propensity scores.
  
  
  RESULTS
  The cohort consisted of 1,989 patients: 98.5% male and a mean age of 74 yrs. For treatment, 44% of subjects received beta-lactam+fluoroquinolone and 56% received beta-lactam+macrolide. Unadjusted 30-day mortality was 27% for beta-lactam+fluoroquinolone and 24% for beta-lactam+macrolide (p=.11). In the multilevel models, the use of beta-lactam+fluoroquinolone was not significantly associated with 30-day mortality (odds ratio 1.05, 95% confidence interval 0.85-1.30). However, the use of beta-lactam+fluoroquinolone was significantly associated with increased mean length of stay (incidence rate ratio 1.30, 95% confidence interval 1.27-1.33).
  
  
  CONCLUSIONS
  We found no significant difference for 30-day mortality but did demonstrate an association with increase in length of stay associated with the use of beta-lactam + fluoroquinolone. Randomized controlled trials are needed to determine the most effective antibiotics regimes for patients with severe pneumonia.
authors.affiliation: VERDICT/South Texas Veterans Health Care System, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Bryan Z
authors.initials: BZ
authors.lastname: Wilson
authors.forename: Antonio
authors.initials: A
authors.lastname: Anzueto
authors.forename: Marcos I
authors.initials: MI
authors.lastname: Restrepo
authors.forename: Mary Jo V
authors.initials: MJ
authors.lastname: Pugh
authors.forename: Eric M
authors.initials: EM
authors.lastname: Mortensen
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D004359:Drug Therapy, Combination; D005260:Female; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007902:Length of Stay; D016015:Logistic Models; D018942:Macrolides / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000401:mortality; D017410:Practice Guidelines as Topic; D057216:Propensity Score; D012189:Retrospective Studies; D047090:beta-Lactams / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D018942:Macrolides; D047090:beta-Lactams