The validity and acceptability of a text-based monitoring system for pediatric asthma studies.

A meaningful analysis in research requires robust, valid data. Paper diaries allow the collection of data from individuals over time but are notorious for poor compliance and validity. SMS-technology is a novel method for data collection in medical research. Time-tagged SMS are transferred directly to an electronic file. We used SMS to collect symptoms and peak flow rate (PEFR) meter readings from 32 children with asthma. Parents responded first to five SMS daily for 7 days during an asymptomatic period and then for 14 days during a cold. Compliance with use of PEFR meter and SMS system were assessed. Digital PEFR meters enabled data download at the end of the study to confirm validity of transmitted data. Parents of 24 participants provided feedback about this data collection tool. Mean (±SD) "SMS-diary and PEFR-meter compliance" were 96% (±8) and 84% (±21) during baseline and 91% (±12) and 82% (±20) during cold respectively. Correctly reported PEFR values were found in 65.5% of all cases, in 8.3% PEFR values sent were "self-invented" and 2.4% of values were missing. All of the 22 parents completing the baseline questionnaire were happy to use SMS for this study. Of the 20 parents completing the follow up questionnaire, 95% (19/20) found the system user-friendly, 55% (11/20) would be more likely to participate in studies if they were using SMS data collection and 25% (5/20) were "sometimes unhappy" about receiving messages. This real-time capture of data is well accepted and could avoid some of the pitfalls of backfilled paper diaries.