Reliability and responsiveness of measures of pain in people with osteoarthritis of the knee: a psychometric evaluation

Katie V Turner,Bryan M Moreton,David A Walsh,Nadina B Lincoln

doi:10.3109/09638288.2016.1161840

Katie V Turner, Bryan M Moreton + Show 2 more

Open Access

https://doi.org/10.3109/09638288.2016.1161840

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Abstract

Purpose: To examine the fit between data from the Short Form McGill Pain Questionnaire (SF-MPQ-2) and the Rasch model, and to explore the reliability and internal responsiveness of measures of pain in people with knee osteoarthritis. Methods: Participants with knee osteoarthritis completed the SF-MPQ-2, Intermittent and Constant Osteoarthritis Pain questionnaire (ICOAP) and painDETECT. Participants were sent the same questionnaires 3 and 6 months later. Results: Fit to the Rasch model was not achieved for the SF-MPQ-2 Total scale. The Continuous subscale yielded adequate fit statistics after splitting item 10 on uniform DIF for gender, and removing item 9. The Intermittent subscale fit the Rasch model after rescoring items. The Neuropathic subscale had relatively good fit to the model. Test–retest reliability was satisfactory for most scales using both original and Rasch scoring ranging from fair to substantial. Effect sizes ranged from 0.13 to 1.79 indicating good internal responsiveness for most scales. Conclusions: These findings support the use of ICOAP subscales as reliable and responsive measure of pain in people with knee osteoarthritis. The MPQ-SF-2 subscales found to be acceptable alternatives.Implications for RehabilitationThe McGill Pain Questionnaire short version 2 is not a unidimensional scale in people with knee osteoarthritis, whereas three of the subscales are unidimensional.The McGill Pain Questionnaire short version 2 Affective subscale does not have good measurement properties for people with knee osteoarthritis.The McGill Pain Questionnaire short version 2 and the Intermittent and Constant Osteoarthritis Pain scales can be used to assess change over time.The painDETECT performs better as a screening measure than as an outcome measure.

Highlights

Measures of pain have been developed to assess pain characteristics and severity in people with osteoarthritis (OA)
Fit to the Rasch model was not achieved for the SF-MPQ-2 Total scale
Effect sizes ranged from 0.13 to 1.79 indicating good internal responsiveness for most scales. These findings support the use of Intermittent and Constant Osteoarthritis Pain questionnaire (ICOAP) subscales as reliable and responsive measure of pain in people with knee osteoarthritis

Summary

Introduction

Measures of pain have been developed to assess pain characteristics and severity in people with osteoarthritis (OA). Overall pain severity is quantified by combining responses to questions that target specific dimension of the pain experience. The Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire was developed to assess two kinds of OA pain [2] based on the aspects of pain that were identified as distinct and important by focus groups of people with OA.[3] Constant pain was characterized as a continuous aching sensation, and intermittent pain was described as being severe but transient. It has been proposed that a total score may be a useful measure of overall pain severity in OA.[2] Moreton et al [4] reported that the Constant and Intermittent subscales of the ICOAP fit the Rasch model following removal of a few items, but raised some concerns over the external validity of the

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