The association between pain and disability.
A clearer understanding of how pain intensity relates to disability could have important implications for pain treatment goals and definitions of treatment success. The objectives of this study were to determine the optimal pain intensity rating (0-10 scale) cutpoints for discriminating disability levels among individuals with work-related carpal tunnel syndrome (CTS) and low back (LB) injuries, whether these cutpoints differed for these conditions and for different disability measures, and whether the relationship between pain intensity and disability was linear in each injury group. Approximately 3 weeks after filing work injury claims, 2183 workers (1059 CTS; 1124 LB) who still had pain completed pain and disability measures. In the LB group, pain intensity rating categories of 1-4, 5-6, and 7-10 optimally discriminated disability levels for all four disability measures examined. In the CTS group, no pain intensity rating categorization scheme proved superior across all disability measures. For all disability measures examined, the relationship between pain intensity and disability level was linear in the CTS group, but nonlinear in the LB group. Among study participants with work-related back injuries, when pain level was 1-4, a decrease in pain of more than 1-point corresponded to clinically meaningful improvement in functioning, but when pain was rated as 5-10, a 2-point decrease was necessary for clinically meaningful improvement in functioning. The findings indicate that classifying numerical pain ratings into categories corresponding to levels of disability may be useful in establishing treatment goals, but that classification schemes must be validated separately for different pain conditions.
Turner
Judith A
JA
Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, 1959 NE Pacific St., Room BB1517a Box 356560, Seattle, WA 98195-6560, USA Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA, USA Occupational Epidemiology and Health Outcomes Program, Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health and Community Medicine, Seattle, WA, USA Washington State Department of Labor and Industries, Olympia, WA, USA Department of Biostatistics, University of Washington School of Public Health and Community Medicine, Seattle, WA, USA Department of Health Services, University of Washington School of Public Health and Community Medicine, Seattle, WA, USA.
Franklin
Gary
G
Heagerty
Patrick J
PJ
Wu
Rae
R
Egan
Kathleen
K
Fulton-Kehoe
Deborah
D
Gluck
Jeremy V
JV
Wickizer
Thomas M
TM
D000328:Adult; D000704:Analysis of Variance; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000145:classification / Q000523:psychology*; D005260:Female; D006801:Humans; D016014:Linear Models; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D012189:Retrospective Studies