title: The moderating effect of obesity on cognitive-behavioral pain treatment outcomes.
abstract: OBJECTIVE
  To assess the effects of body mass index on cognitive-behavioral pain treatment outcomes for chronic low back pain.
  
  
  METHODS
  Retrospective analyses of data from a clinical trial were performed, with body mass index used to divide patients into obese and non-obese groups for comparison.
  
  
  METHODS
  VA medical center outpatient clinic.
  
  
  METHODS
  Veterans (N = 74) receiving outpatient care through the VA.
  
  
  METHODS
  Delivery of a 10-week cognitive-behavioral pain treatment intervention.
  
  
  METHODS
  The Numerical Rating Scale (pain intensity), Roland Morris Disability Questionnaire (disability), Veteran's SF-36 (health-related quality of life), and Beck Depression Inventory (emotional functioning) were administered pre- and post-treatment.
  
  
  RESULTS
  The study included 42 obese and 32 non-obese participants, most of whom were male (89%). The average body mass index was 32.44 kg/m², with average pain intensity rated as 6.59 out of 10. There were no pre-treatment differences in outcome measures between the groups. Repeated measures ANOVAs revealed main effects of Time on all but one outcome (Mental Component score), indicating that the cognitive-behavioral interventions were largely effective. However, Time-body mass index (BMI) group interactions revealed that non-obese participants showed greater improvement following treatment than did their obese counterparts on measures of disability (P < 0.05), physical aspects of quality of life (P < 0.01), and emotional functioning (P < 0.05).
  
  
  CONCLUSIONS
  Standard cognitive-behavioral pain treatment did not yield comparable outcomes for obese and non-obese participants. Results suggest a potential moderating role of BMI in low back pain outcomes. Future work with other pain conditions, including examination of potential mechanisms through which BMI impacts treatment outcomes, is recommended.
authors.affiliation: Department of Veterans Affairs-VA Connecticut Healthcare System, West Haven, Connecticut 06516, USA. John.Sellinger1@va.gov
authors.forename: John J
authors.initials: JJ
authors.lastname: Sellinger
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Clark
authors.forename: Marc
authors.initials: M
authors.lastname: Shulman
authors.forename: Patricia H
authors.initials: PH
authors.lastname: Rosenberger
authors.forename: Alicia A
authors.initials: AA
authors.lastname: Heapy
authors.forename: Robert D
authors.initials: RD
authors.lastname: Kerns
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002986:Clinical Trials as Topic; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000523:psychology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D010147:Pain Measurement; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome