ORIGINAL ARTICLE   Free access

European Journal of Physical and Rehabilitation Medicine 2022 February;58(1):68-75

DOI: 10.23736/S1973-9087.21.06729-0

Copyright © 2021 EDIZIONI MINERVA MEDICA

language: English

Responsiveness and minimal important change of the Pain Catastrophizing Scale in people with chronic low back pain undergoing multidisciplinary rehabilitation

Marco MONTICONE ^{1, 2} ✉, Igor PORTOGHESE ¹, Barbara ROCCA ³, Andrea GIORDANO ⁴, Marcello CAMPAGNA ¹, Franco FRANCHIGNONI ⁵

¹ Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; ² Unit of Neurorehabilitation, Department of Neuroscience and Rehabilitation, G. Brotzu Hospital, Cagliari, Italy; ³ Unit of Physical Medicine and Rehabilitation, Institute of Lissone, IRCCS - ICS Maugeri, Lissone, Monza-Brianza, Italy; ⁴ Unit of Bioengineering, Institute of Veruno, IRCCS - ICS Maugeri, Veruno, Novara, Italy; ⁵ Department of Physical Medicine and Rehabilitation, Institute of Tradate, IRCCS - ICS Maugeri, Tradate, Varese, Italy

BACKGROUND: The Pain Catastrophizing Scale (PCS), a widely used tool to assess catastrophizing related to spinal disorders, shows valid psychometric properties in general but the minimal important change (MIC) is still not determined.
AIM: The aim of this study was to assess responsiveness and MIC of the PCS in individuals with chronic low back pain (LBP) undergoing multidisciplinary rehabilitation.
DESIGN: Prospective observational study.
SETTING: The setting was outpatient rehabilitation hospital.
POPULATION: Two hundred and five patients with chronic LBP.
METHODS: Before and after an 8-week multidisciplinary rehabilitation program, 205 patients completed the Italian version of the PCS (PCS-I). We calculated the PCS-I responsiveness by distribution-based methods (effect size [ES], standardized response mean [SRM], and minimum detectable change [MDC]) and anchor-based methods [receiver operating characteristic (ROC) curves]. After the program, participants completed a 7-point global perceived effect scale (GPE), based on which they were classified as “improved” vs. “stable.” ROC curves computed the best cut-off level (taken as the MIC) between the two groups. ROC analysis was also performed on subgroups according to patients’ baseline PCS scores.
RESULTS: ES, SRM and MDC were 0.71, 0.67 and 7.73, respectively. ROC analysis yielded an MIC of 8 points (95% confidence interval [CI]: 6-10; area under the curve [AUC]: 0.88). ROC analysis of the PCS subgroups confirmed an MIC of 8 points (95%CI: 6-10) for no/low catastrophizers (score <30, N.=159; AUC: 0.90) and indicated an MIC of 11 points (95%CI: 8-14) for catastrophizers (score >30, N.=33; AUC: 0.84).
CONCLUSIONS: The PCS-I showed good ability to detect patient-perceived clinical changes in chronic LBP postrehabilitation. The MIC values we determined provide a benchmark for assessing individual improvement in this clinical context.
CLINICAL REHABILITATION IMPACT: The present study calculated - in a sample of people with chronic LBP - the responsiveness and MIC of the PCS. These values increase confidence in interpreting score changes, enhancing their meaningfulness for both research and clinical contexts.

KEY WORDS: Low back pain; Catastrophization; Pain; Rehabilitation; Exercise; Psychometrics