Trends in asthma prevalence, hospitalization risk, and inhaled corticosteroid use among Alaska Native and nonnative Medicaid recipients younger than 20 years

Abstract

Few trend data on asthma prevalence exist for U.S. indigenous populations, and none exist for Alaska Natives. To document the epidemiologic features of asthma in Alaska Natives and nonnatives stratified by urban (Anchorage) and rural (non-Anchorage) residence. We conducted a retrospective review of Alaskans younger than 20 years enrolled in Medicaid during 1999 to 2002. Asthma was defined as a claim for International Classification of Diseases, Ninth Revision, codes 493.0x to 493.9x plus asthma-associated medication during the same calendar year. Among 117,080 Medicaid enrollees, the 4-year asthma prevalence was 3.1% and was 40% to 90% greater for urban residents regardless of race. Yearly prevalence increased from 1.0% to 2.2% (P < .001), with increases in all subgroups. Of 4 predominantly Alaska Native census areas, the area with resident pediatricians and previous participation in asthma research had a 4-year asthma prevalence 5- to 11-fold higher than the other areas. Among persons with asthma, yearly hospitalization risk decreased (from 9.3% to 6.8%; P = .02) concurrent with an increase in the yearly use of inhaled corticosteroids (from 50% to 64%; P < .001). Urban Alaska Natives had the greatest decrease in hospitalization risk and the greatest increase in inhaled corticosteroid use. Relatively dramatic demographic differences and temporal trends in asthma prevalence occurred in the absence of known differences or changes in risk factor prevalences. This suggests a role for differences in the use of asthma as a diagnosis for respiratory illness. Failure to diagnose and thus treat asthma may affect outcomes because decreases in hospitalization risk were temporally associated with increases in inhaled corticosteroid use.