Trends in compliance with bronchodilator inhaler use between follow-up visits in a clinical trial

Study objective: To assess objectively measured, long-term trends in compliance with physician-prescribed metered-dose inhaler (MDI) use during a clinical trial. Design: A prospective study. Setting: The Lung Health Study, a 5-year clinical trial to determine the effect of special intervention with an intensive smoking cessation program and bronchodilator therapy in cigarette smokers 35 to 60 years of age with minimal to moderate airflow limitation due to COPD. Participants: Two hundred thirty-one participants who were issued an MDI with an attached Nebulizer Chronolog (NC) (Forefront Technologies Inc; Lakewood, Colo) which electronically records the date and time of each MDI actuation. One hundred two participants were not informed of the recording capabilities of the attached NC, while 129 participants were aware of the NC's monitoring function. Intervention: Following an initial 12- week period of counseling, participants returned to the clinic every 4 months. Measurements and results: Analysis of the data from the NC collected over a period of 2 years indicates that compliance with the prescribed medication regimen was best immediately following each follow-up visit and gradually declined during the interval between follow-up visits. The level of compliance after each visit was lower for each successive follow-up. These trends could not be observed from self-report or weighing the medication canisters at follow-up visits. The participants who were informed of the NC's function and who were provided with detailed feedback about their inhaler use generally showed better compliance.