title: Metered-dose inhaler adherence in a clinical trial.
abstract: We studied patterns of inhaler usage in a sample of participants from two centers in the Lung Health Study clinical trial. The inhaler, containing either ipratropium bromide or a placebo, was prescribed to be taken as two inhalations three times daily. For 4 months we recorded adherence by both self-report (n = 95) and canister weight change (n = 70). We compared these results with data obtained from a microprocessor monitoring device, the Nebulizer Chronolog (NC), which records the date and time of each inhaler actuation. Seventy-three percent of the participants reported using the inhaler an average of three times daily; however, NC data showed that only 15% of the participants actually used the inhaler an average of 2.5 or more times per day. Canister weight overestimated adherence because only 62% of the NC sets contained the prescribed two actuations. Fourteen percent showed a pattern of actuation of their inhalers more than 100 times in a 3-h interval. We interpret this usage pattern to reflect deliberate emptying of inhalers to appear to be in good compliance with the prescribed program. We conclude that self-report and weighing of inhaler canisters overestimate adherence to the prescribed regimens. Furthermore, a substantial number of monitored inhaler users appear to deliberately dump their medication prior to follow-up visits.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland.
authors.forename: C S
authors.initials: CS
authors.lastname: Rand
authors.forename: R A
authors.initials: RA
authors.lastname: Wise
authors.forename: M
authors.initials: M
authors.lastname: Nides
authors.forename: M S
authors.initials: MS
authors.lastname: Simmons
authors.forename: E R
authors.initials: ER
authors.lastname: Bleecker
authors.forename: J W
authors.initials: JW
authors.lastname: Kusek
authors.forename: V C
authors.initials: VC
authors.lastname: Li
authors.forename: D P
authors.initials: DP
authors.lastname: Tashkin
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D001249:Asthma / Q000188:drug therapy*; D005260:Female; D006801:Humans; D009241:Ipratropium / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010349:Patient Compliance
chemical_list: D009241:Ipratropium