Instruments such as the Radboud Skills Questionnaire [RASQ] and the Disability of Arm Shoulder and Hand Questionnaire [DASH] are not commonly used in general practice because they take too much time to complete. By assessing the concurrent validity, we examined whether the Visual Analog Scale [VAS] could serve as an alternative simple proxy to measure functional limitations in patients suffering from complex regional pain syndrome 1 [CRPS 1] of the upper extremities.
We asked patients afflicted with CRPS 1 of the upper extremities to indicate their functional limitations on the VAS and assessed the concurrent validity by comparing the results with the scores from the RASQ and the DASH.
Fifty-seven patients [37 females] with a median disease duration of 1.9 years [interquartile ranges 0.9–4.3] were included. Self-perceived activity limitations on the VAS were 5.4 ± 2.2. Average score for the RASQ was 140.1 ± 39.2 and for the DASH 64.3 ± 17.3. We found a good correlation between the VAS and the RASQ [R2 = 0.57], and the DASH [R2 = 0.64].
The VAS may serve as a simple proxy to assess functional limitations in patients suffering from CRPS 1 of the upper extremities. However, it may only be used as an add-on to valid instruments in clinical practice and should not replace established and validated assessments.