Use of pen-based electronic diaries in an international clinical trial of asthma

The use of pen-based electronic diaries was evaluated in an international clinical trial of asthma. The study compared bambuterol with salmeterol in nocturnal asthma, and was carried out in Italy, Norway, and the United Kingdom. Two hundred and sixty-five patients were enrolled, of whom 135 were randomized and 118 completed the eight-week study period. Patients completed the electronic diary at home each morning and evening throughout the eight-week study period. Data could be entered into the diary only within specified time "windows." No retrospective entry was permitted Data collection was very satisfactory Ninety-four percent of patients enrolled completed their diaries during the run-in period to the required standard for inclusion in the study (at least five out of the last seven days of the run-in complete). After randomization entries were completed on 86% of scheduled occasions. At the randomization stage, a review facility was provided for the investigator which gave a summary of the run-in data to indicate whether the patient met the inclusion criteria. This saved work for the investigators, and helped to reduce the rate of incorrect randomization compared to a previous similar study. Data handling was substantially faster than in similar paper-based studies, contributing to locking the database well within schedule. Thus, the potential gains seen with this method in earlier evaluation studies have been realized in a foil-scale clinical trial.