Validation of a Mobile App-Based Visual Analog Scale for Appetite Measurement in the Real World: A Randomized Digital Clinical Trial

There has been no validated digital tool for measuring appetite with a visual analog scale (VAS) through a mobile app using participants' smart phones for data collection in virtual settings. To fill the gap, we developed a digital VAS and conducted a digital cross-over clinical trial by comparing appetite responses measured by this digital tool versus paper-based VAS in 102 participants in a free-living environment. Participants consumed either a 230 or 460 kcal breakfast in randomized order in two virtual sessions, and their appetite was measured over the next 4 h using both tools. The results revealed no significant difference in hunger, fullness, satiety, or desire to eat measured by digital and paper VAS. Paper VAS resulted in a higher prospective consumption score than digital VAS; the difference (1.1 out of 100 points) was statistically significant but not practically relevant. Bland and Altman analysis also indicated consistency in the results from the two methods. In conclusion, digital VAS on a smart phone is a validated tool for appetite measurement in the real world; it provides a new way for researchers to leverage participants' mobile devices for appetite data collection in digital trials.

Automated summary

There is currently no validated digital tool available for measuring appetite using a visual analog scale (VAS) on participants' smart phones in virtual settings. In order to address this gap, a digital VAS was developed and a digital cross-over clinical trial was conducted comparing appetite responses measured by this digital tool to a paper-based VAS. The results showed no significant difference in hunger, fullness, satiety, or desire to eat between the digital and paper VAS. The digital VAS is therefore a validated tool for measuring appetite in the real world, providing researchers with a new way to collect appetite data in digital trials using participants' mobile devices.