title: Does pain-catastrophising mediate the effect of tai chi on treatment outcomes for people with low back pain?
abstract: OBJECTIVE
  There is evidence to support the effectiveness of tai chi for reducing pain-related symptoms across multiple musculoskeletal conditions, however, the mechanism(s) are unclear. This study explores the role of pain-catastrophising as a possible mediator in the relationship between practising tai chi and back pain symptoms.
  
  
  METHODS
  Exploratory mediation analyses using a Baron and Kenny approach and bootstrapping methods were employed as a secondary analysis of data from a previously published randomised controlled trial.
  
  
  METHODS
  Adults with persistent low back pain were recruited via community advertisement in Sydney, NSW, Australia.
  
  
  METHODS
  A 10-week tai chi intervention and a wait-list control.
  
  
  METHODS
  Patients completed self-assessments of pain intensity and bothersomeness using 0-10 numerical rating scales, disability using the Roland Morris Disability Questionnaire and pain catastrophising using the Pain Coping Strategies Questionnaire pre and post intervention.
  
  
  RESULTS
  The results suggest partial mediation, by which a reduction in catastrophising explained approximately 1/3 of the effect on pain intensity and bothersomeness and 2/3 of the effect on disability.
  
  
  CONCLUSIONS
  As the first known mediation analysis of tai chi for reducing low back pain-symptoms, it provides initial evidence that it may do so by having an effect on cognitive appraisal outcomes such as pain-catastrophising and information for choosing appropriate process measures for future studies. As tai chi is growing in popularity as an alternative treatment for patients with chronic musculoskeletal conditions, it is important to gain a better understanding of how it might work using confirmatory mediation analysis alongside future RCTs.
authors.affiliation: Nuffield Department of Population Health, The George Institute for Global Health, University of Oxford, Oxford, United Kingdom. Electronic address: amanda.hall@georgeinstitute.ox.ac.uk.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Hall
authors.affiliation: Musculoskeletal Division, The George Institute for Global Health, The University of Sydney, Sydney, NSW, Australia(1); EMGO+ Institute, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Kamper
authors.affiliation: Centre for Biostatistics, Institute of Population Health, The University of Manchester, Manchester Academic Health Science Centre, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Emsley
authors.affiliation: Musculoskeletal Division, The George Institute for Global Health, The University of Sydney, Sydney, NSW, Australia(1).
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Maher
mesh_terms: D000368:Aged; D058443:Catastrophization / Q000453:epidemiology* / Q000503:physiopathology; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D026302:Tai Ji; D016896:Treatment Outcome
keywords: Disability; Low back pain; Pain; Pain-catastrophising; Randomised controlled trial; Tai chi