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Back in the days of pen and paper clinical trials monitoring, something familiar but disconcerting caught my attention as I got out of the car. There in the next car sat a patient busy filling in his diary card with peak expiratory flow (PEF) readings and symptoms for the past month. Mentioning this to the investigating consultant, he called the patient in, commended him for having a complete diary, and then as he rubbed his finger over it, said, “oh dear the ink is still wet!” Having observed this, I concluded that there had to be a better way of recording diary data. The answer came in the early 1990s with the development of e-spirometric diaries. Chowienczyk et al compared paper versus electronic recording of spirometry data, demonstrating that 33 per cent of completed entries were either invented, mistimed or misread, and were often retrospectively entered (1). Since then, other studies have confirmed that paper diaries often contain invented data (2,3). |
