"It's Not Pain It's Discomfort": Development and Investigation of a Discomfort Measurement Scale.

Logically, anecdotally and empirically, there appears to be a shared understanding of the difference between 'pain' and 'discomfort'. Although discomfort is commonly referred to in medical literature, it has never been objectively measured or its properties examined. This study devised a visual analogue discomfort scale (VAS-D) and obtained a sample of n=128 outpatient musculoskeletal physiotherapy patients who complete it alongside a traditional visual analogue pain scale (VAS-P) and the EQ5D-5L. Demographic data was also collected. The purpose of the investigation was to preliminarily validate the VAS-D as a psychometric index. Scale scores and correlations are examined in the entire sample and in sub-samples split by gender and pain severity. Scale correlations were primarily moderate indicating the VAS-D measures a related but distinct construct to pain and there was a statistically significant difference between discomfort scores when compared to pain. This indicates the VAS-D measures a related, but distinct construct to pain. 7.8% of respondents endorsed the VAS-D but scored zero on the VAS-P. The relationships between pain and discomfort scores held face validity, adding empirical evidence to a theoretical relationship between the constructs. As a preliminary study, it appears the VAS-D is a valid scale that is distinct from a VAS-P. Data supports a hypothesis that VAS-P scores may be lower or even absent in the concurrent presence of a VAS-D measure. Clinical implications and direction for future investigation are briefly discussed.