Methicillin-resistant Staphylococcus aureus-associated hospitalizations among the American Indian and Alaska native population

Abstract

Background: American Indians and Alaska Natives (AI/ANs) have had documented outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) infection but, to our knowledge, no studies have examined MRSA infection among this population nationally. We describe MRSA-associated hospitalizations among the approximately 1.6 million AI/ANs who receive care at Indian Health Service health care facilities nationwide.

Methods: We used hospital discharge data from the Indian Health Service National Patient Information Reporting System to determine the rate of MRSA-associated hospitalizations among AI/ANs who used Indian Health Service health care in 1996-2005 and in the comparison periods 1996-1998 and 2003-2005. Hospitalization rates among AI/ANs were examined by year, age group, sex, and region. MRSA-associated diagnoses were also examined. Rate comparisons were performed using Poisson regression analysis. Comparison of rates to those of the general United States population was made for 2003-2005 by means of the Nationwide Inpatient Sample.

Results: Between comparison periods, the rate of MRSA-associated hospitalization increased from 4.6 to 50.6 hospitalizations per 100,000 AI/ANs (P<.01), with increases in both sexes, all age groups, and all regions. By 2005, MRSA was the causative organism for the majority (52%) of all S. aureus-associated hospitalizations. The most common associated diagnosis was skin and soft-tissue infection, which accounted for 59% of MRSA-associated diagnoses. In 2003-2005, the age-adjusted rate among AI/ANs was 58.8 hospitalizations per 100,000 persons, compared with 84.7 hospitalizations per 100,000 persons in the general US population.

Conclusions: MRSA-associated hospitalizations have increased significantly among AI/ANs served by Indian Health Service health care facilities. Clinicians should have a high index of suspicion for MRSA infection in AI/ANs, especially in those with a diagnosis of skin and soft-tissue infection.