The moderating effect of obesity on cognitive-behavioral pain treatment outcomes.
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.
Sellinger
John J
JJ
Department of Veterans Affairs-VA Connecticut Healthcare System, West Haven, Connecticut 06516, USA. John.Sellinger1@va.gov
Clark
Elizabeth A
EA
Shulman
Marc
M
Rosenberger
Patricia H
PH
Heapy
Alicia A
AA
Kerns
Robert D
RD
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