Increasing trend in the rate of infectious disease hospitalisations among Alaska Native people

Abstract

Objectives: To examine the epidemiology of infectious disease (ID) hospitalisations among Alaska Native (AN) people.

Methods: Hospitalisations with a first-listed ID diagnosis for American Indians and ANs residing in Alaska during 2001-2009 were selected from the Indian Health Service direct and contract health service inpatient data. ID hospitalisations to describe the general US population were selected from the Nationwide Inpatient Sample. Annual and average annual (2007-2009) hospitalization rates were calculated.

Results: During 2007-2009, IDs accounted for 20% of hospitalisations among AN people. The 2007-2009 average annual age-adjusted ID hospitalisation rate (2126/100,000 persons) was higher than that for the general US population (1679/100,000; 95% CI 1639-1720). The ID hospitalisation rate for AN people increased from 2001 to 2009 (17%, p < 0.001). Although the rate during 2001-2009 declined for AN infants (< 1 year of age; p = 0.03), they had the highest 2007-2009 average annual rate (15106/100,000), which was 3 times the rate for general US infants (5215/100,000; 95% CI 4783-5647). The annual rates for the age groups 1-4, 5-19, 40-49, 50-59 and 70-79 years increased (p < 0.05). The highest 2007-2009 age-adjusted average annual ID hospitalisation rates were in the Yukon-Kuskokwim (YK) (3492/100,000) and Kotzebue (3433/100,000) regions; infant rates were 30422/100,000 and 26698/100,000 in these regions, respectively. During 2007-2009, lower respiratory tract infections accounted for 39% of all ID hospitalisations and approximately 50% of ID hospitalisations in YK, Kotzebue and Norton Sound, and 74% of infant ID hospitalisations.

Conclusions: The ID hospitalisation rate increased for AN people overall. The rate for AN people remained higher than that for the general US population, particularly in infants and in the YK and Kotzebue regions. Prevention measures to reduce ID morbidity among AN people should be increased in high-risk regions and for diseases with high hospitalisation rates.

Keywords: Alaska; Alaska Native; hospitalisations; infectious disease; lower respiratory tract infection.

Fig. 1

A) Annual rates of first-listed infectious disease (ID) hospitalisations among Alaska Native people, Alaska, and for the general US population, 2001–2009 and B) Annual proportions of first-listed and of any-listed ID hospitalisations in all hospitalisations among Alaska Native people, Alaska, 2001–2009. *First-listed ID hospitalisations are hospitalisations where the first diagnosis is an ID, any-listed ID hospitalisations are hospitalisations with an ID ICD-9-CM code listed anywhere on the discharge record. Rate per 100,000 persons of corresponding group. Rates for Alaska Native people were determined from the Indian Health Service (IHS) direct and contract health service inpatient dataset. Rates for the general US population used the Nationwide Inpatient Sample (NIS) to represent all of the US population.