Risk factors for hospital-acquired pneumonia outside the intensive care unit: a case-control study.

Background: Hospital-acquired pneumonia (HAP) is one of the leading nosocomial infections and is associated with high morbidity and mortality. Numerous studies on HAP have been performed in intensive care units (ICUs), whereas very few have focused on patients in general wards. This study examined the incidence of, risk factors for, and outcomes of HAP outside the ICU.

Methods: An incident case-control study was conducted in a 600-bed hospital between January 2006 and April 2008. Each case of HAP was randomly matched with 2 paired controls. Data on risk factors, patient characteristics, and outcomes were collected.

Results: The study group comprised 119 patients with HAP and 238 controls. The incidence of HAP outside the ICU was 2.45 cases per 1,000 discharges. Multivariate analysis identified malnutrition, chronic renal failure, anemia, depression of consciousness, Charlson comorbidity index ≥3, previous hospitalization, and thoracic surgery as significant risk factors for HAP. Complications occurred in 57.1% patients. The mortality attributed to HAP was 27.7%.

Conclusions: HAP outside the ICU prevailed in patients with malnutrition, chronic renal failure, anemia, depression of consciousness, comorbidity, recent hospitalization, and thoracic surgery. HAP in general wards carries an elevated morbidity and mortality and is associated with increased length of hospital stay and increased rate of discharge to a skilled nursing facility.