Excess costs and utilization associated with methicillin resistance for patients with Staphylococcus aureus infection.
OBJECTIVE
To determine differences in healthcare costs between cases of methicillin-susceptible Staphylococcus aureus (MSSA) infection and methicillin-resistant S. aureus (MRSA) infection in adults.


METHODS
Retrospective study of all cases of S. aureus infection.


METHODS
Department of Veterans Affairs hospital and associated clinics.


METHODS
There were 390 patients with MSSA infections and 335 patients with MRSA infections.


METHODS
We used medical records, accounting systems, and interviews to identify services rendered and costs for Minneapolis Veterans Affairs Medical Center patients with S. aureus infection with onset during the period from January 1, 2004, through June 30, 2006. We used regression analysis to adjust for patient characteristics.


RESULTS
Median 6-month unadjusted costs for patients infected with MRSA were $34,657, compared with $15,923 for patients infected with MSSA. Patients with MRSA infection had more comorbidities than patients with MSSA infection (mean Charlson index 4.3 vs 3.2; P < .001). For patients with Charlson indices of 3 or less, mean adjusted 6-month costs derived from multivariate analysis were $51,252 (95% CI, $46,041-$56,464) for MRSA infection and $30,158 (95% CI, $27,092-$33,225) for MSSA infection. For patients with Charlson indices of 4 or more, mean adjusted costs were $84,436 (95% CI, $79,843-$89,029) for MRSA infection and $59,245 (95% CI, $56,016-$62,473) for MSSA infection. Patients with MRSA infection were also more likely to die than were patients with MSSA infection (23.6% vs 11.5%; P < .001). MRSA infection was more likely to involve the lungs, bloodstream, and urinary tract, while MSSA infection was more likely to involve bones or joints; eyes, ears, nose, or throat; surgical sites; and skin or soft tissue (P < .001).


CONCLUSIONS
Resistance to methicillin in S. aureus was independently associated with increased costs. Effective antimicrobial stewardship and infection prevention programs are needed to prevent these costly infections.
Filice
Gregory A
GA
Division of Infectious Diseases, Department of Medicine, University of Minnesota Medical School, University of Minnesota School of Public Health, Minneapolis, Minnesota, USA. filic001@umn.edu
Nyman
John A
JA
Lexau
Catherine
C
Lees
Christine H
CH
Bockstedt
Lindsay A
LA
Como-Sabetti
Kathryn
K
Lesher
Lindsey J
LJ
Lynfield
Ruth
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000188:drug therapy / Q000191:economics* / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D017048:Health Care Costs; D006787:Hospitals, Veterans / Q000191:economics*; D006801:Humans; D008297:Male; D008712:Methicillin / Q000494:pharmacology; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008875:Middle Aged; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000191:economics* / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects; D055815:Young Adult
D000900:Anti-Bacterial Agents; D008712:Methicillin