Geographic variation in the use of inhaled corticosteroids in children

Abstract

Objective: A limited amount of evidence exists on geographic variation in the use of prescription drugs in the United States. There is also a lack of evidence on geographic variation in health care for children. One category of prescription drugs for which there may be considerable variation in use is inhaled corticosteroids. Among children, inhaled corticosteroids are known for their use in asthma and are generally regarded as being underused for that condition. However, these drugs may be prescribed for other respiratory conditions in children. Some of that use is controversial, and there is concern that inhaled corticosteroids may be overused. Because both underuse and overuse pose risks to children, it is important to understand how these drugs are used. The purpose of this study is to assess the geographic variation in the use of inhaled corticosteroids by children in Medicaid. Methods: This study is a retrospective analysis of 2005-2007 Medicaid enrollment, medical, and prescription drug files from the lower 48 states. Children 0-18 years of age continuously enrolled in fee-for-service Medicaid for a calendar year were included. A child was identified as receiving an inhaled corticosteroid if there was a claim for an inhaled corticosteroid during the year in which the child was enrolled. We used the driving area for clinical care method to determine the area treatment ratio for the local area around every ZIP code. Regression analysis was used to calculate the predicted probability of receiving an inhaled corticosteroid at the individual level, controlling for demographics, clinical characteristics, and health care utilization. ZIP code level area treatment ratios were calculated by dividing the number of children receiving inhaled corticosteroids in the local area around a ZIP code by the summed predicted probabilities of children in the area. Results: In 2005, 6.34% of children received an inhaled corticosteroid. In 2006 and 2007, 6.11% and 6.27% received an inhaled corticosteroid, respectively.