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.

Complementary and Alternative Medicine Use and Adherence With Pediatric Asthma Treatment

“…Although the Medication Adherence Scale used in the study has been shown to be reliable and valid, the authors of many studies have documented the tendency for patients to overestimate their adherence, and we did not use an electronic doser to validate parent-reported adherence. 9,28 Our adherence scores were high and may have overestimated actual adherence. In addition, we only collected data 1 year after the start of CAM therapy.…”

Patient compliance in a clinical trial with inhaled budesonide in children with mild asthma

“…The possibility that the actual number of remaining doses overestimates drug adherence ("clicking" the inhaler without inhaling) cannot be ruled out. This kind of overuse or "test firing" has been shown by others with the use of an electronic medication monitor in the inhaler [5,8]. This electronic instrument cannot confirm that the medication was inhaled or used correctly, but only when and how often the inhaler was actuated.…”

“…This has been performed using an electronic inhaler timer device (Nebulizer Chronolog; Forefront Technologies Inc., Lakewood, CO, USA), and has repeatedly shown that adherence to asthma medication is generally poor. These studies show that only about 50±77% of the medication is used as prescribed by the doctor [3±6], and that when asked, patients overestimate the use of their own medication 50±90% of the time [3,7,8]. Poor compliance with prescribed therapy can lead to difficulties in assessing disease severity as the expected effect of the treatment given is missing, which may in fact influence the clinician in changing to a different, and sometimes a more complicated treatment regimen instead of focusing on improving the patient compliance.…”

Perceived Discrimination, Patient Trust, and Adherence to Medical Recommendations Among Persons with Sickle Cell Disease

“…Additionally, the adherence literature has noted a tendency for patients to generally overestimate adherence in using medications. 27,28 A more systematic analysis of specific adherence behaviors, particularly related to the use of medications, may yield an even higher rate of nonadherence in sickle cell.…”