Epidemiology, Antibiotic Therapy, and Clinical Outcomes in Health Care-Associated Pneumonia: A UK Cohort Study

Background. The recently introduced concept of health care-associated pneumonia (HCAP), referring to patients with frequent healthcare contacts and at higher risk of contracting resistant pathogens, is controversial. Methods. This prospective observational study recorded the clinical features, microbiology, and outcomes in a UK cohort of hospitalized patients with pneumonia. The primary outcome was 30-day mortality. Logistic regression was used to adjust for confounders when determining the impact of HCAP on clinical outcomes. Results. A total of 20.5% of patients met the HCAP criteria. HCAP patients were older than patients with community-acquired pneumonia (CAP) (median 76 y, IQR 65-83 vs 65 y, IQR 48-77; P < .0001) and more frequently had major comorbidities (62.1% vs 45.2%; P < .0001). Patients with HCAP had higher initial severity compared to CAP patients (Pneumonia Severity Index, mean 3.7 [SD 1.1] vs mean 3.1 [SD 1.3]; P < .0001) but also worse functional status using the Eastern Cooperative Oncology Group scale (mean 2.4 [SD 1.44] vs mean 1.4 [SD 1.13]; P < .0001) and more frequently had treatment restrictions such as do not resuscitate orders (59.9% vs 29.8%; P < .0001). Consequently mortality was increased (odds ratio [OR] 2.15 [1.44-3.22]; P = .002) in HCAP patients on univariate analysis. Multivariate analysis suggested this relationship was primarily due to confounders rather than a higher frequency of treatment failure due to resistant organisms (adjusted OR .97 [.61-1.55]; P = .9). The frequencies of Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Gram-negative Enterobacteriaceae were low in both cohorts. Conclusions. HCAP is common in the United Kingdom and is associated with a high mortality. This increased mortality was primarily related to underlying patient-related factors rather than the presence of antibiotic-resistant pathogens. This study did not establish a clear indication to change prescribing practices in a UK cohort.