Treatment procedures and associated medical costs of methicillin-resistant Staphylococcus aureus infection in Japan: A retrospective analysis using a database of Japanese employment-based health insurance

Objectives: This study aimed to determine the patient characteristics, treatment procedures, and medical costs of methicillin-resistant Staphylococcus aureus infections in clinical practice in Japan. Methods: Using the MinaCare database of healthcare information covering nearly 3 million individuals, of which 90% were aged 20-59 years, we extracted and analyzed data of patients who were aged > 15 years and diagnosed with methicillin-resistant S. aureus during hospitalization between April 2010 and August 2015. Results: A total of 684 patients with methicillin-resistant S. aureus infection were listed in the database, of which 365 were eligible to be included in this study. Mean patient age was 52.9 years, and 31.5% of the patients were females. Methicillin-resistant S. aureus bacteremia was the most common methicillin-resistant S. aureus infection (32.9%) with a mean age of 48.5 years, followed by pneumonia (24.1%) with a mean age of 61.0 years and methicillin-resistant S. aureus surgical site infection (6.3%) with a mean age of 49.7 years. Vancomycin was the most frequently prescribed anti-methicillin-resistant S. aureus drug used as the first-line therapy (68.5%), followed by teicoplanin (14.2%), linezolid (7.9%), arbekacin (5.8%), and daptomycin (3.6%). The mortality rate was 11.0%, and the mean treatment duration was 13.3 days. The median total medical cost per patient was US$5083. The median treatment cost for methicillin-resistant S. aureus bacteremia was the highest among the methicillin-resistant S. aureus infections at US$9099, followed by methicillin-resistant S. aureus pneumonia at US$3676 and surgery site infections at US$2084. Conclusion: Although the proportion of patients with methicillin-resistant S. aureus is very small in the employment-based health insurance database, methicillin-resistant S. aureus bacteremia is the most common methicillin-resistant S. aureus infection in the working-age population and requires the highest medical cost. Methicillin-resistant S. aureus pneumonia is more common in the elderly and is a cause of high mortality.