A Therapeutic Strategy for All Pneumonia Patients: A 3-Year Prospective Multicenter- Cohort Study Using Risk Factors for Multidrug Resistant Pathogens To Select Initial Empiric Therapy.

Background: Empiric therapy of pneumonia is currently based on the site of acquisition (community or hospital), but could be chosen, based on risk factors for multidrug-resistant (MDR) pathogens, independent of site of acquisition.

Methods: We prospectively applied a therapeutic algorithm based on MDR risks, in a multicenter cohort study of 1,089 patients, with community-acquired pneumonia (CAP, n=656), health care-associated pneumonia (HCAP, n=238), hospital-acquired pneumonia (HAP, n=140) and ventilator-associated pneumonia (VAP, n=55).

Results: 82.5% of patients were treated according to the algorithm, with 4.3% receiving inappropriate therapy. The frequency of MDR pathogens varied, respectively, with VAP (50.9%), HAP (27.9%), HCAP (10.9%) and CAP (5.2%). Those with ≥2 MDR risks had MDR pathogens more often than those with 0-1 risk (25.8% vs 5.3%, p< 0.001). The 30-day mortality rates were: VAP (18.2%), HAP (13.6%), HCAP (6.7%) and CAP (4.7%), and were lower in patients with 0-1 MDR risks than in those with ≥2 MDR risks (4.5% vs. 12.5%, p<0.001). In multivariate logistic regression analysis, 5 risk factors (age≥75 years, hematocrit<30%, albumin<3.0g/dl, BUN≥21 mg/dl and chronic liver disease), as well as hypotension (systolic BP≤90mmHG) and inappropriate therapy were significantly correlated with 30-day mortality, while the classification of pneumonia type (VAP, HAP, HCAP, CAP) was not.

Conclusions: Individual MDR risk factors can be used in a unified algorithm to guide and simplify empiric therapy for all pneumonia patients, and were more important than the classification of site of pneumonia acquisition, in determining 30 day mortality.

Trial registration: Japan Medical Association Center for Clinical Trials JMA-IIA00146.