Guideline-concordant antibiotic therapy is not associated with improved outcomes in healthcare-associated pneumonia

Background: Healthcare-associated pneumonia (HCAP) guidelines were first proposed in 2005 but have not yet been validated. The objective of this study was to compare 30-day mortality and length of stay (LOS) in HCAP patients treated with either guideline-concordant HCAP (GC-HCAP) therapy or guideline-concordant community-acquired pneumonia (GC-CAP) therapy.

Methods: We performed a retrospective cohort study of >150 hospitals in the Veterans Health Administration. Patients were included if they had ≥1 HCAP risk factor and received antibiotic therapy within 48 hours of admission. Patients were excluded if they received ICU care, had cardiovascular or respiratory organ failure, or received invasive mechanical ventilation and/or vasopressors. We determined independent risk factors for 30-day mortality with a multivariable logistic regression model including baseline characteristics, individual HCAP risk factors, comorbidities, and organ failure as dichotomous covariates. Propensity scores were calculated for the probability to receive GC-HCAP therapy and incorporated into a second logistic regression model.

Results: A total of 15,071 patients met study criteria and received GC-HCAP therapy (8.0%), GC-CAP therapy (75.7%), or non-guideline-concordant therapy (16.3%). GC-HCAP patients were more likely to have neoplastic disease; whereas, GC-CAP patients had a higher prevalence of other comorbidities, tobacco use, and recent medication use. In multivariable regression, recent hospital admission (OR 2.47, 95% CI 2.10-2.91) and GC-HCAP therapy (2.13, 1.82-2.48) were the strongest predictors of 30-day mortality. Hematologic organ failure, non-invasive mechanical ventilation, neoplastic disease, renal organ failure, and cerebrovascular disease were also independent risk factors. Use of cardiovascular medications, inhaled corticosteroids, and tobacco were protective. GC-HCAP therapy continued to be an independent risk factor for 30-day mortality (OR 2.12, 95% CI 1.82-2.48) in the propensity score analysis.

Conclusions: GC-HCAP therapy is not associated with improved survival in HCAP patients.