Improving Inhaler Adherence in a Clinical Trial Through the Use of the Nebulizer Chronolog (6)

In a preliminary study, the weight of each MDI actuation was found to be 0.0676 g. Therefore, the average number of actuations per day was calculated by dividing the mean daily usage in grams by 0.0676. Mean canister weight sets per day was calculated by dividing the average number of actuations by two, on the assumption that each set contained the prescribed two actuations.
Nebulizer Chronolog: Nebulizer Chronolog data were used to derive several measures of adherence based on actual usage patterns and adherence to the prescribed regimen. Each treatment day was defined to start at 4:00 am and end at 3:59 am the next day to account for late-night usage. To determine the appropriateness of inhaler-use patterns, all NC actuations were divided into daily sets of use, which is an index of the number of separate times that the inhaler is used each day. Participants were instructed to use the inhaler no more frequently than at 4-h intervals. Starting with the first inhaler actuation, any actuation that occurs within a 3-h period is counted as a part of the same set. This window gave adequate latitude to participants who might use the inhaler at slightly shorter intervals. We found that 90 percent of the last actuations in a set occurred with 60 min after the first actuation, indicating that few participants space their inhaler use widely within the 3-h time window. The number of sets each day was averaged over the number of days the NC was available for use to derive the measure mean NC sets per day.