Comparative responsiveness of pain outcome measures among primary care patients with musculoskeletal pain.
BACKGROUND
Comparative responsiveness data are needed to inform choices about pain outcome measures.


OBJECTIVE
To compare responsiveness of pain intensity, pain-related function, and composite measures, using data from a randomized trial and observational study.


METHODS
Analysis of responsiveness.


METHODS
A total of 427 adults with persistent back, hip, or knee pain were recruited from primary care.


METHODS
Participants completed Brief Pain Inventory, Chronic Pain Grade (CPG), Roland disability, SF-36 bodily pain, and pain global rating of change measures. We used the global rating as the anchor for standardized response mean and receiver operating characteristic curve analyses. We used the distribution-based standard error of measurement to estimate minimally important change. To assess responsiveness to the trial intervention, we evaluated standardized effect size statistics stratified by trial arm.


RESULTS
All measures were responsive to global improvement and all had fair-to-good accuracy in discriminating between participants with and without improvement. SF bodily pain was less responsive than other measures in several analyses. The 3-item PEG was similarly responsive to full Brief Pain Inventory scales. CPG and SF bodily pain were less responsive to the trial intervention and did not perform well among participants with hip/knee pain. Agreement between anchor and distribution-based methods was modest.


CONCLUSIONS
If a brief measure is desired, the 3-item PEG is more responsive than the SF bodily pain scale. CPG and SF bodily pain scales may be relatively poor choices for trial outcome assessment. Both anchor and distribution-based methods should be considered when determining clinically important change.
Krebs
Erin E
EE
Center on Implementing Evidence-Based Practice, Roudebush VA Medical Center, Indianapolis, IN 46202, USA. krebse@iupui.edu
Bair
Matthew J
MJ
Damush
Teresa M
TM
Tu
Wanzhu
W
Wu
Jingwei
J
Kroenke
Kurt
K
D000328:Adult; D004185:Disability Evaluation; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D010146:Pain / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D010147:Pain Measurement / Q000706:statistics & numerical data*; D010361:Patients / Q000706:statistics & numerical data; D011320:Primary Health Care; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires