Guideline-based antibiotics and mortality in healthcare-associated pneumonia.

Abstract

BACKGROUND: Guidelines recommend administration of antibiotics with activity against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa for treatment of healthcare-associated pneumonia (HCAP). It is unclear if this therapy improves outcomes for patients with HCAP. OBJECTIVE: To determine if administration of guideline-similar therapy (GST) was associated with a reduction in 30-day mortality for HCAP. DESIGN: Multi-center retrospective study. PARTICIPANTS: Thirteen hundred and eleven admissions for HCAP in six Veterans Affairs Medical Centers. INTERVENTIONS: Each admission was classified as receiving GST, anti-MRSA or anti-pseudomonal components of GST, or other non-HCAP therapy initiated within 48 hours of hospitalization. Association between 30-day mortality and GST was estimated with a logistic regression model that included GST, propensity to receive GST, probability of recovering an organism from culture resistant to antibiotics traditionally used to treat community-acquired pneumonia (CAP-resistance), and a GST by CAP-resistance probability interaction. MAIN MEASURES: Odds ratios and 95% confidence intervals [OR (95% CI)] of 30-day mortality for patients treated with GST and predicted probability of recovering a CAP-resistant organism, and ratio of odds ratios [ROR (95% CI)] for treatment by CAP-resistance probability interaction. KEY RESULTS: Receipt of GST was associated with increased odds of 30-day mortality [OR = 2.11 (1.11, 4.04), P = 0.02)] as was the predicted probability of recovering a CAP-resistant organism [OR = 1.67 (1.26, 2.20), P < 0.001 for a 25% increase in probability]. An interaction between predicted probability of recovering a CAP-resistant organism and receipt of GST demonstrated lower mortality with GST at high probability of CAP resistance [ROR = 0.71(≤1.00) for a 25% increase in probability, P = 0.05]. CONCLUSIONS: For HCAP patients with high probability of CAP-resistant organisms, GST was associated with lower mortality. Consideration of the magnitude of patient-specific risk for CAP-resistant organisms should be considered when selecting HCAP therapy.