Asthma medication use among rural U.S. adults 18 and older

Background: Approximately 8% of adults living in rural areas have asthma. An important strategy for managing asthma is the regular use of preventive medications and controlled use of acute medications. However, little is known about asthma in rural adults and factors associated with their medication use.

Objective: To identify factors associated with the use of asthma medications among rural U.S. adults aged 18 and older.

Methods: Data were obtained from the 2006 to 2010 Medical Expenditure Panel Survey (MEPS). Medication use outcome variables include: a. daily use of a preventive asthma medication (yes/no) and b. overuse (3+) of rescue inhalers in last 3 months (yes/no). The Andersen Behavioral Model of Health Care was used to guide the selection of independent variables. The independent variables were categorized as predisposing, enabling and medical need factors. With less than 10% of the data missing, multiple imputation was used to account for the incomplete data. Descriptive statistics including mean and frequency were used to describe the data. Bivariate and multivariate logistic regression models were used to examine the relationship between asthma medication use in rural adults with asthma. Point estimates were weighted to the U.S. non-institutionalized population, and standard errors were adjusted to account for the complex survey design. All analyses were conducted using STATA (version 12).

Results:A total of 909 (weighted sample of 10,145,422) self-reported non-MSA asthmatics age 18 and older were identified. Twenty-seven percent of rural adults with asthma were using a preventive medication on a daily basis and 13.5% reported overusing acute medications. Rural adults who were current smokers were found to be significantly less likely to use a daily preventive medication after controlling for confounders (OR 0.59, CI 0.42 to 0.83). As perceived physical health deteriorated, rural adults were more likely to use a preventive asthma medication daily and were more likely to overuse an acute asthma medication (OR: 1.45, CI: 1.06 to 1.98; OR: 1.49, CI: 1.10 to 2.01 respectively).

Conclusions: This study identified that Andersen’s medical need factors were important predictors of asthma medication use behavior in this sample of rural adults. More research is warranted to identify and evaluate solutions to resolve medical need issues in rural populations to improve asthma care.