MRSA trends in Washington State Workers' Compensation

Objectives: To examine trends in methicillin-resistant Staphylococcus aureus (MRSA) claims in Washington State Workers' Compensation (1998-2006). Methods: The Department of Labor and Industries maintains extensive databases of claims, medical bills, pharmacy, and wage loss. MRSA does not have a specific ICD code and therefore is difficult to study in administrative databases. We identified potential MRSA cases in three ways: injury codes for skin infections or bug bites, supplementary codes for infection with drug-resistant organisms (V09), and a combination of ICD codes and certain antibiotics. A sample of medical records will be reviewed to determine the percentage of cases identified by each method that have a diagnosis of MRSA and the percentage employed in settings at higher risk for MRSA. Factors to be examined include diagnosis, culture site, infection type (skin or soft tissue versus invasive), drug resistance, work setting, known history of working with infected patients, treatments, and outcomes. Results: Claims for skin infections and bug bites increased dramatically between 1998 and 2006; skin infections increased to 1256 from 341 claims per year and bug bites increased to 677 cases from 58. Cases identified by V09 codes increased to 132 from 6. The percentage of cases confirmed by medical record review and the accuracy of each method for identifying cases will be discussed. Rates among health-care workers, corrections employees, and first responders will be examined. Conclusion: This study will lead to a better understanding of the scope of the problem and to improved methods for studying MRSA using administrative databases.