Objective: The aim of this study was to determine the risk of mortality, functional decline and institutionalization, as well as the hospital cost associated with patients with methicillin-resistant Staphylococcus aureus (MRSA) infection in an Acute Geriatric Unit (AGU).
Material and methods: We retrospectively gathered data on patients admitted to the AGU over a 5-year period (from 1/1/2001 to 1/1/06). Mortality, institutionalization, functional impairment at discharge, length of hospital stay, and hospital costs were compared between patients with and without MRSA. MRSA infection was documented by the microbiology department using culture and antibiogram, as well as by clinical diagnosis of hospital infection registered in the medical record.
Results: Data were obtained from 47 patients with MRSA (mean age 86.15+/-5.5 years) and from 4281 patients without MRSA (mean age 85.25+/-6 years). MRSA-infected patients had higher mortality (25.5% vs. 7.7%, p<0.001), worse functional status at discharge (Barthel index 39.43+/-33.05 vs. 55.24+/-34.99, p<0.01) and more frequent institutionalization (29% vs. 9%, p<0.001). Longer length of hospital stay (22.15+/-13.67 vs. 10.64+/-7.69 days, p<0.001) and higher hospital cost per patient (7517.71+/-4639.59 vs 3611.21+/-2609.98 euro, p<0.001) were also observed. In the multivariate analysis adjusted by age, sex, and baseline functional and cognitive status, MRSA infection was independently associated with higher mortality (OR=3.92; 95% CI=1.95-7.86), worse functional status at discharge (OR=2.48; 95% CI=1.22-5.01), institutionalization at discharge (OR=6.50; 95% CI=2.60-12.22), and substantial increase in length of hospital stay (Beta coefficient=11.55 days; 95% CI=9.32-13.75).
Conclusion: MRSA infection in the AGU is associated with higher mortality, worse functional status at discharge and a higher incidence of institutionalization, as well as significantly longer length of stay and higher hospital costs.