Impact of community-acquired infection on acquisition of nosocomial infection, length of stay, and mortality in adult blunt trauma patients

The incidence of community-acquired infections (CA) and how it relates to the incidence of nosocomial infections (NI) in the adult blunt trauma population is unknown. We evaluated this incidence and assessed the impact of age on morbidity and mortality. Prospective data were collected on blunt trauma patients admitted >48 h over a 2-year period. Each patient was screened for infection by an infectious disease specialist. The Centers for Disease Control and Prevention (CDC) guidelines were used to diagnose infection. Of the 2,645 patients admitted, 86% were <65 years of age and 14% were ≥65 years of age. There was not a significant difference in Injury Severity Score (ISS) between the two groups. A total of 201 (8.8%) of the younger patients were diagnosed with CA; of these, 52.2% acquired a NI. Additionally, 65 (17.4%) of the older patients were diagnosed with a CA; of these, 57% acquired a NI. The combination of CA and NI led to the most significant increases in intensive care (ILOS), hospital (HLOS) length of stay, and mortality. Patients with the CA had a significantly greater risk of obtaining an NI in both age groups. The relative risk (RR) of an older patient presenting with a CA was two times greater than in patients <65 years old. The greatest relative risk of mortality (RRM) was demonstrated with the combination of CA and NI, and age. However, once infected with both CA and NI, younger patients had a greater RRM (5.0 vs. 3.9) in the group-specific comparison. CA significantly increases the risk of blunt trauma patients acquiring an NI. The combination of CA and NI led to the most significant increases in HLOS, ILOS, and mortality. Increased age is associated with a significantly higher incidence of CA, ILOS, HLOS, and mortality. Once infected with both CA and NI, younger patients have a greater risk of mortality.