Transition questionnaire (TRANS-Q)

Transition ratings, or Global Perceived Effect scales, are recommended as a core outcome measure in chronic pain trials [13] and have been used as an external criterion to determine responsiveness [14] or Minimal Important Change (MIC) [3] of other measurement instruments. A transition questionnaire (TRANS-Q), modified from Jaschke et al. [15], was used for asking the participants about their experienced change in pain after the intervention with the question: “Did your knee pain change since you entered this project?” Response options were: “It is unchanged,” “It is better,” and “It is worse.” The ‘unchanged’ response is given a score of 0, and no further questions are asked. The responses “It is better” and “It is worse” bring up a seven-point scale, with scores spanning from −7 (worst) to +7 (best), respectively. For the purpose of this study, a clinically important change in pain was defined as a TRANS-Q score of at least 2 (+2: a little better; −2: a little worse). No change was defined as a TRANS-Q score of 0 (no change) or +1/-1 (Almost the same, hardly any better/worse at all). The transition questionnaire was implemented in the hosting trial after the trial commenced and therefore applicable to only a subset of the trial participants. The transition questionnaire was administered only at the end-of-treatment visit.