Development of a web-based ecological momentary assessment tool to measure day-to-day variability of the symptoms in patients with Sjögren's disease.

Objectives: To develop and validate a web-based ecological momentary assessment (EMA) tool to enhance symptoms monitoring among patients with Sjögren's disease (SjD).

Methods: Consecutive adults with SjD were enrolled in this pilot observational study. Participants used the WebApp over a 3-month period, for the daily collection of individual EULAR Sjögren's Syndrome Patient Reported Index (ESSPRI) scales and separate assessment of eyes and mouth dryness, using 0-10 numerical scales. Primary outcome was the measure of the interdaily variability of symptoms. Data collected through the WebApp were compared with those obtained with paper-based questionnaires administered during a final visit, using distinct approaches (predicted error, maximum negative error and maximum positive error). User experience was assessed using the System Usability Scale (SUS) score.

Results: Among the 45 participants, 41 (91.1%) were women. Median age was 57 years (IQR: 49-66). Daily variability of symptoms ranged between 0.5 and 0.8 points across the scales. Over the 3-month period, the predicted error ranged between -1.2 and -0.3 points of the numerical scales. The greatest differences were found for fatigue (-1.2 points (IQR: -2.3 to -0.2)) and ESSPRI score (-1.2 points (IQR: -1.7 to -0.3)). Over the last 2 weeks, the predicted error ranged between - 1.2 and 0.0 points. Maximum negative error ranged between -2.0 and -1.0 points, and maximum positive error between -0.3 and 0.0 points. Median SUS score was 90 (IQR: 85-95).

Conclusion: Our results demonstrate the usability and the relevance of our web-based EMA tool for capturing data that closely reflects daily experiences of patients with SjD.