Response shift in severity assessment of hand eczema with visual analogue scales

BACKGROUND: Hand eczema is a common and fluctuating disease. Visual analogue scales (VASs) are used to assess disease severity, both currently and when at its worst. However, such patient-reported outcomes may be at risk of being flawed owing to recall bias or response shifts.

OBJECTIVE: To explore whether the current state of hand eczema severity affects the recollection of the eczema when at its worst, thus resulting in a response shift.

METHODS: We utilized a dataset from a recent clinical trial examining nurse counselling of hand eczema patients. The patients assessed the disease severity currently (VASnow ) and when at its worst (VASworst ), both at baseline and at a 6-month follow-up.

RESULTS: The patients who reported improvement during the course were generally more likely to downwardly adjust their assessment of VASworst than patients reporting unchanged or worsened severity (odds ratio 1.94, p = 0.017). No other determinants were found.

CONCLUSION: Patients may downwardly adjust their assessment of worst-ever disease severity according to the assessment of present disease severity. Regular photographic documentation of the hand eczema along with the patient's self-monitoring of symptoms as part of the treatment course could perhaps counteract this tendency for there to be severity habituation.