The association of antibiotic treatment regimen and hospital mortality in patients hospitalized with Legionella pneumonia.
BACKGROUND
Guidelines recommend azithromycin or a quinolone antibiotic for treatment of Legionella pneumonia. No clinical study has compared these strategies.


METHODS
We performed a retrospective cohort analysis of adults hospitalized in the United States with a diagnosis of Legionella pneumonia in the Premier Perspectives database (1 July 2008-30 June 2013). Our primary outcome was hospital mortality; we additionally evaluated hospital length of stay, development of Clostridium difficile colitis, and total hospital cost. We used propensity-based matching to compare patients treated with azithromycin vs a quinolone. All analyses were repeated on a subgroup of more severely ill patients, defined as requiring intensive care unit admission or mechanical ventilation or having a predicted probability of hospital mortality in the top quartile for all patients.


RESULTS
Legionella pneumonia was diagnosed in 3152 adults across 437 hospitals. Quinolones alone were used in 28.8%, azithromycin alone was used in 34.0%, and 1.8% received both. Crude hospital mortality was similar: 6.6% (95% confidence interval [CI], 5.0%-8.2%) for quinolones vs 6.4% (95% CI, 5.0%-7.9%) for azithromycin (P = .87); after propensity matching (n = 813 in each group), mortality remained similar (6.3% [95% CI, 4.6%-7.9%] vs 6.5% [95% CI, 4.8%-8.2%], P = .84 for the whole cohort, and 14.9% [95% CI, 10.0%-19.8%] vs 18.3% [95% CI, 13.0%-23.6%], P = .36 for the more severely ill). There was no difference in hospital length of stay, development of C. difficile, or total hospital cost.


CONCLUSIONS
Use of azithromycin alone or a quinolone alone for treatment of Legionella pneumonia was associated with similar hospital mortality. Few patients receive combination therapy.
Division of Critical Care Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx.
Hayley B
HB
Gershengorn
Division of Critical Care Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx.
Adam
A
Keene
Department of Pharmacy, Columbia University, New York Presbyterian Hospital, New York.
Amy L
AL
Dzierba
Department of Critical Care Medicine, Sunnybrook Health Sciences Center, Toronto Department of Anesthesiology Interdepartmental Division of Critical Care, University of Toronto, Ontario, Canada Department of Anesthesiology, Columbia University, New York, New York.
Hannah
H
Wunsch
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017963:Azithromycin / Q000627:therapeutic use*; D003015:Clostridium Infections / Q000139:chemically induced; D015331:Cohort Studies; D003092:Colitis / Q000139:chemically induced; D005260:Female; D017721:Hospital Costs; D017052:Hospital Mortality; D006801:Humans; D007876:Legionellosis / Q000150:complications / Q000188:drug therapy* / Q000401:mortality*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015363:Quinolones / Q000627:therapeutic use*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D000900:Anti-Bacterial Agents; D015363:Quinolones; D017963:Azithromycin
Legionella; azithromycin; hospital mortality; pneumonia; quinolones