PURPOSE:Healthcare associated pneumonia (HCAP) presents similarly to community acquired pneumonia (CAP), but has different risk factors, bacteriology and outcomes. HCAP is more likely to be caused by a resistant organism and treated with an inappropriate initial antibiotic (IIA). While HCAP and IIA impart worsened outcomes in pneumonia, it is not known whether their effects on mortality are modified by respiratory failure.
METHODS:We examined pneumonia hospitalizations over a three year period. The diagnosis of pneumonia required signs and symptoms of infection along with radiographic evidence of an infiltrate. Hospital death served as the endpoint. HCAP was present if a patient met one of the following: recent hospitalization, nursing home residence, chronic hemodialysis, or immunosuppression. The need for mechanical ventilation (MV) was assessed at admission.
RESULTS:Of 639 patients, 257 (40.2%) needed MV (74.4% HCAP) and 382 did not (62.6% HCAP). The rates of bacteremia did not differ in HCAP vs. CAP regardless of MV. Such resistant organisms as methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa were more prevalent in HCAP, while such sensitive organisms as Haemophilus influenzae and Streptococcus pneumoniae were more likely to cause CAP, regardless of MV. Both MV and non-MV groups with HCAP were at increased risk of receiving IIA, and had a substantially higher crude mortality than CAP. In Cox proportional hazards models adjusting for confounders, both HCAP (HR 4.50, 95% CI 1.36–14.91) and IIA (HR 2.12, 95% CI 1.01–4.49) in non-MV and IIA in MV (HR 2.16, 95% CI 1.41–3.30) emerged as significant independent risk factors for increased hospital mortality.
CONCLUSION:Among pneumonia patients regardless of respiratory failure, IIA is an independent predictor of hospital mortality, and MV does not modify its effect.
CLINICAL IMPLICATIONS:Since IIA is the only modifiable risk factor for mortality among patients with pneumonia and respiratory failure, early and reliable risk stratification and appropriate treatment are critical to optimize outcomes.
DISCLOSURE:Marya Zilberberg, None.