A double-edged sword: Exhaust the ozone layer or ban ozone depleting asthma drugs?

The U.S. Food and Drug Administration (FDA) announced in March 2005 that the production and sale of all chlorofluorocarbons (CFC) propelled albuterol inhalers would be banned effective December 31, 2008. FDA’s action was motivated by an environmental goal to protect the ozone layer by reducing the emission of CFCs, as mandated by several provisions of the Clean Air Act. Currently, there are several FDA approved albuterol inhalers that contain a propellant called hydrofluoralkane (HFA) in the market as safe and effective alternatives to the CFC propelled inhalers. However, HFA inhalers do not have generic substitutes as did their CFC counterparts, and thus have substantially higher out-of-pocket (OOP) costs for patients.

In this study, we evaluate the implications of this ban on affordable CFC albuterol inhalers for patients with asthma. Prior research has consistently shown that greater OOP costs are associated with reduced medication use and increases in emergency department (ED) visits and hospitalizations. It is unknown whether this ban is associated with reductions in use of albuterol inhalers and increases in adverse outcomes such as ED visits and hospitalizations among individuals with asthma.

Using a unique longitudinal pharmacy and medical claims-level dataset from 2004 through 2010 on a large group of privately insured individuals, we are able to follow CFC and HFA inhaler use as well as outpatient and inpatient utilization over time comparing a) before the announcement of the ban, b) after the announcement of the ban, but before the ban became effective, and c) after the ban became effective. The data, obtained from a benefits consulting firm represent employees and their dependents for 40 geographically diverse US employers, thus provides an opportunity for conducting a nationally generalizable study.

Our sample includes 57,714 children and 121,677 adults diagnosed with asthma during 2004 and 2010 who have at least six months of follow-up period in our data. Average OOP for a monthly supply of the branded HFA inhalers is double that of the generic CFC inhalers ($26 vs. $13). Surprisingly, we find that individuals start switching to HFA inhalers soon after the ban is announced as we estimate a gradual increase in HFA inhalers with a proportional decrease in CFC inhalers between April 2005 and December 2008. After the ban on CFC inhalers is implemented, while CFC inhalers are no longer used, the HFA inhaler use remains stable, suggesting that individuals who use albuterol inhalers transition to the HFA inhalers before the ban is implemented. These results hold both for children and adults.  Also interestingly, we observe differential response to the ban by the plan OOP for generic versus branded drugs. As expected, individuals with a larger OOP differential between the generic versus branded drugs delay their transition from CFC to inhalers. Moreover, their use of albuterol inhalers drops after the implementation of the ban. In ongoing analyses, we are investigating differential responses to the ban with asthma severity, as well as the impact of the ban on subsequent outcomes such as asthma related ED visits and hospitalizations.