Real-world assessment of a metered-dose inhaler with integrated dose counter

Currently available metered dose inhalers (MDIs) do not track the remaining number of doses, indicating the need for a device that accurately monitors medication use. In an open-label study at 37 outpatient centers, patients > or =4 years old with asthma or chronic obstructive pulmonary disease requiring short-acting 32-agonists received two actuations of albuterol hydrofluoroalkane (HFA) [Ventolin HFA: GlaxoSmithKline], 90 microg twice daily, via a novel MDI with an integrated dose counter until all 200 actuations were completed. Concordance between counter readings, diary card-recorded actuations, and canister weights were measured in patients who completed > or =90% of the labeled actuations (n = 224). Adverse events and patient satisfaction were assessed in the intent-to-treat population (n = 268). In 43,865 recorded actuations, 333 counter versus diary discrepancies occurred (discrepancy rate of 0.76%), and 88% of discrepancies were by one to two actuations. Forty-seven percent of patients had no discrepancies. Incidence of the device firing without changes in counter readings was very low (0.09%). Mean expected actuations based on canister weights (184) were slightly lower than mean counter and diary-reported actuations (200 each). At baseline, 62% of patients reported anxiety about not knowing the quantity of medication remaining in their inhaler. On study completion, 92% expressed satisfaction with the dose counter and 92% agreed it would help prevent them from running out of medication. The adverse event profile showed that albuterol HFA was well tolerated. Integrated MDI counters are a useful and reliable tool for tracking a patient's medication supply.