Outcomes of patients with healthcare-associated pneumonia: worse disease or sicker patients?

BACKGROUND

Healthcare-associated pneumonia (HCAP) is an entity distinct from community-acquired pneumonia (CAP). HCAP has a higher case-fatality rate, due either to HCAP organisms or to the health status of HCAP patients. The contribution of HCAP criteria to case-fatality rate is unknown.

METHODS

We conducted a retrospective review of adult patients admitted with a diagnosis of pneumonia from July 2007 through November 2011 to 491 US hospitals. HCAP was defined as having at least 1 of the following: prior hospitalization within 90 days, hemodialysis, admission from a skilled nursing facility, or immune suppression. We compared characteristics of patients with CAP and patients with HCAP and explored the contribution of HCAP criteria to case-fatality rate in a hierarchical generalized linear model.

RESULTS

Of 436,483 patients hospitalized with pneumonia, 149,963 (34.4%) had HCAP. Compared to CAP patients, HCAP patients were older, had more comorbidities, and were more likely to require intensive care unit (ICU) care. In-hospital case-fatality rate was higher among patients with HCAP, compared to those with CAP (11.1% vs 5.1%, P < .001). After adjustment for demographics, comorbidities, presence of other infections, early ICU admission, chronic and acute medications, early tests and therapies, and length of stay, HCAP remained associated with increased case-fatality rate (odds ratio [OR], 1.35 [95% confidence interval (CI), 1.32-1.39]); odds of death increased for each additional HCAP criterion (OR [95% CI]: 1 criterion, 1.27 [1.23-1.31], 2 criteria, 1.55 [1.49-1.62], and 3 or more criteria, 1.88 [1.72-2.06]).

CONCLUSIONS

After adjustment for differences in patient characteristics, HCAP was associated with greater case-fatality rate than CAP. This difference may be due to HCAP organisms or to HCAP criteria themselves.