Background & Aims

‘Pain catastrophizing’ is routinely assessed in clinical studies of people with or at risk of pain, as well as in experimental studies of healthy volunteers investigating mechanisms of acute pain. It has been shown to be predictive of adverse pain outcomes, such as distress and disability. One of the most widely used measures of pain catastrophizing is the Pain Catastrophizing Scale (PCS) [1]. The PCS has been shown to have high test-retest reliability and good construct validity. However, it should be noted that patients were not involved in the development of the instrument. Moreover, a qualitative approach to investigate in-depth how people understand and respond to the items of the PCS (i.e. content validity) is lacking.
The aim of this study was to investigate how patients with chronic pain and people without chronic pain understand and respond to the items of the PCS.

Methods

A cognitive interview with a verbal probing technique [2,3] was conducted with 5 patients with neuropathic (NeuP) pain or a combination of NeuP and nociplastic/nociceptive pain, 3 people with nociplastic/nociceptive pain and 3 people without chronic pain. Participants were purposively sampled to ensure a variability in gender, age, ethnicity and socio-economic status. Patients were recruited via the Multidisciplinary Pain Clinic (MPC) of Ghent University Hospital. People without chronic pain were recruited via social media advertisement and snowball sampling. During the interviews cognitive probes were used asking about (1) comprehension of the question, (2) processes used by the respondents to retrieve relevant information from memory and (3) response processes. Interviews were transcribed verbatim and analysed using a reflexive thematic analysis approach [4,5]. Themes were developed using a hybrid deductive-inductive approach to analysis.

Results

Four themes were identified within the data. Theme 1 reflects the comprehensibility and relevance of the items of the PCS, showing that some items were deemed irrelevant or were misunderstood. Theme 2 reflects the importance of taking the broader context into account when interpreting the responses to the items. Theme 3 centred on anxiety for the future that came forward particularly in response to two of the items of the PCS (“…I become afraid my pain will get worse”, “…I wonder whether something serious may happen”). The final theme reflects the struggle to accept pain and the disability and negative emotions associated with it that came up when reflecting upon some of the items.

Conclusions

It is important to critically reflect upon our measurement instruments and to ensure that they measure what they are supposed to measure (content validity). Here we showed that there are some issues with the PCS that may jeopardize the validity of the instrument. Several recommendations are made that may improve the instrument. This study points at the importance of taking patients’ perspectives into account when developing instruments. Seven more interviews are planned to ensure that a diversity of perspectives are obtained.

References

[1] Sullivan, M.J.L., Bishop, S.R. & Pivik, J. (1995). The Pain Catastrophizing Scale: Development and validation. Psychological assessment 7(4):524-532
[2] Beatty, P.C. & Willis, G.B. Research synthesis: the practice of cognitive interviewing. (2007). Public Opinion Quarterly 71(2):287-311
[3] DeWalt, D.A., Rothrock, N., Yount, S. & Stone, A.A. (2007). Evaluation of Item Candidates: The PROMIS Qualitative Item Review. Med Care 45(5):S12-S21 DOI 10.1097/01.mlr.0000254567.79743.e2
[4] Braun, V. & Clarke, V. (2006). Using thematic analysis in psychology. Qualitative Research in Psychology, 3(2):77-101 DOI 10.1191/1478088706qp063oa
[5] Braun V, Clarke V. (2019). Reflecting on reflexive thematic analysis. Qualitative Research in Sport Exercise and Health,11(4):589-97

Presenting Author

Annick De Paepe

Poster Authors

Annick De Paepe

PhD

Ghent University

Lead Author

Geert Crombez

Ghent University

Lead Author

Lynn Laidlaw

Lead Author

Whitney Scott

King's College London

Lead Author

Topics

  • Assessment and Diagnosis