LONG-TERM METERED-DOSE INHALER ADHERENCE IN A CLINICAL-TRIAL

Poor adherence to medication regimens is a well-documented phenomenon in clinical practice and an ever-present concern in clinical trials. L ittle is known about adherence to inhaled medication regimens over ext ended periods. The present paper describes the 2-yr results of the Lun g Health Study (LHS) program, which was developed to maintain long-ter m adherence to an inhaled medication regimen in 3,923 special interven tion participants (as measured by self-report and medication canister weight). The LHS is a double-blind, multicenter, randomized controlled clinical trial of smoking intervention and bronchodilator therapy (ip ratropium bromide or placebo) for early intervention in chronic obstru ctive pulmonary disease (COPD). At the first 4-mo follow-up visit, nea rly 70% of participants reported satisfactory or better adherence. Ove r the next 18 mo, self-reported satisfactory or better adherence decli ned to about 60%. Canister weight classified adherence as satisfactory or better in 72% of participants returning all canisters at 1 yr, and in 70% of the participants returning all canisters at the 2-yr follow -up. Self-reporting confirmed by canister weight classified 48% of par ticipants at 1 yr as showing satisfactory or better adherence. Overuse rs were 50% more likely than others to misrepresent their true smoking status, suggesting that canister weights indicating overuse may be de ceptive. Results of multiple logistic regression analysis indicate tha t the best compliance was found in participants who were married, olde r, white, had more severe airways obstruction, less shortness of breat h, and fewer hospitalizations, and who had not been confined to bed fo r respiratory illnesses. In summary, a structured program for promotin g adherence to an inhaled medication regimen was successful in achievi ng initial satisfactory adherence in the majority of participants; how ever, adherence declined notably from the conclusion of this program t o the first-year follow-up, and more gradually over the second year.