Research Day

Pyomyositis In The United States – Trends And Associations From The Healthcare Utilization Project Nationwide Inpatients Sample Database

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Pyomyositis is a spontaneous infection of skeletal muscle that can lead to abscess formation and sepsis. It was first recognized in tropical regions but is gaining recognition in temperate climates. The purpose of our study was to better describe the characteristics, risk factors, and trends of pyomyositis in the United States.

This study is a retrospective review of data from the Healthcare Utilization Project Nationwide Inpatient Sample Database from 2002-2014. We systematically searched all available ICD-9 codes for inclusion and exclusion criteria to identify cases of pyomyositis. We compiled lists of codes for expected co-occurrences, risk factors, causative organisms, and inpatient procedures. Each group was treated as a single entity for the purpose of analysis.

The database included a total of 100,790,900 discharges accounting for 482,872,274 weighted discharges with 13,011 pyomyositis cases accounting for 62,657 weighted cases. The proportion of discharges with pyomyositis has steadily risen from 0.0054% (95% CI 0.0047, 0.0061) in 2002 to 0.0209% (95% CI 0.0195, 0.0222) in 2014. Co-occurring deep tissue infections implying secondary pyomyositis were identified in 27% of cases, with the remaining majority representing primary pyomyositis. We found significantly higher rates of co-occurrence with HIV and diabetes mellitus. Staphylococcal followed by streptococcal species were the most common bacteria diagnosed.

The rapid increase in pyomyositis cases represents a 3-4 fold increase over our 12 year study period. This study provides additional information about the demographics, frequency, regional distribution, co-occurring conditions, risk factors, inpatient procedures, and causative organisms from patients with pyomyositis in the United States.

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