The association between age, sex, and hospital-acquired infection rates: results from the 2009-2011 National Medicare Patient Safety Monitoring System.

Objective: To define the relationships between age, sex and hospital-acquired infection (HAI) rates in a national cohort of hospitalized patients.

Methods: Analysis of chart-abstracted Medicare Patient Safety Monitoring System data from randomly selected medical records of patients hospitalized between January 1, 2009, and December 31, 2011, for acute cardiovascular disease, pneumonia, or major surgery associated with 1 of 6 HAIs. Patients were stratified into 6 groups. We then analyzed the association of age, sex, and 2 outcomes; the rate of occurrence of HAI for patients who were at risk and the rate of patients having at least 1 HAI.

Results: Among 85,461 patients, all groups except younger female surgical patients had higher catheter-associated urinary tract infection (CAUTI) rates than male patients. After adjustment for comorbidities, there was no overall evidence of higher HAI rates among elderly patients. In patients with acute cardiovascular disease, women had higher rates of HAIs. Among patients with pneumonia, there was no significant difference in the rate of HAIs among most age and sex groups. Among surgical patients, all age and sex groups had a significantly higher adjusted rate of developing at least 1 HAI except females 65 years of age or older. Similar results were seen for the outcome of the occurrence rate of HAIs.

Conclusions: There was not an overall increased risk of HAIs among older patients hospitalized for acute cardiovascular disease, pneumonia, and major surgery after adjustment for comorbidities. The relationship between sex and the rate of HAIs varied depending upon the underlying acute reason for hospitalization.