Rural-urban disparities in asthma medication use in U.S. adults aged 50-64

Background: Rural-urban disparities in asthma medication use are well documented in younger populations, however little is known about adults age 50 to 64 years. This growing age group is important due to its increasing healthcare needs and future impact on Medicare costs. Research Objective: To compare asthma medication use among adults aged 50-64 years in urban and rural communities. Study Design: Data were obtained from the 2006 and 2008 Medical Expenditure Panel Survey (MEPS). Outcome variables measuring asthma medication use were: a. daily use of a preventive asthma medication (yes/no) and b. overuse (3+) rescue inhalers in last 3 months (yes/no). Rurality was defined using Metropolitan Statistical Areas (MSA) and Rural Urban Continuum Codes (RUCCs). The Andersen Behavioral Model of Health Care was used to guide the selection of potential confounding variables. Two multiple logistic regression models were conducted to examine the relationships between asthma medication use and Rurality. We controlled for patient demographics, perceived health status, Charlson Co-morbidity Index, attitudes towards health and health insurance and health insurance coverage. Point estimates were weighted to the U.S. non-institutionalized population, and standard errors accounted for the complex survey design. Results: The final sample comprised of 801 adults (50-64years), representing about 8 million U.S. non-institutionalized asthmatics. About 80% of the sample was from metropolitan areas. Only 35% of the 50 to 64 year old asthmatics were currently using a preventive asthma medication while approximately 12% were overusing rescue inhalers. No significant rural-urban differences were observed in the use of preventive asthma medication (RUCC model: Odds Ratio [OR] =1.00, CI = 0.92, 1.09 & MSA model: OR = 1.15, CI= 0.87, 1.54). However, Rurality was associated with significantly higher odds of overusing rescue medications (RUCC model: OR =1.38, CI = 1.21 to 1.57 & MSA model: OR = 3.16, CI= 1.67 to 5.96). Conclusions: Our results suggest overuse of rescue asthma medications in rural communities, which is associated with increased morbidity and mortality among asthma patients. Interventions are warranted to resolve medication use problems in an effort to achieve asthma control and prevent sicker populations from progressing into Medicare eligibility.