This study examined the sensitivity of a behavioral observation method for the assessment of arthritis pain as an outcome measure in clinical drug trials.
The subjects were 33 rheumatoid arthritis patients who were receiving either an active experimental drug or a placebo. Disease activity measures, self-reports of pain, and pain behavior observations were completed for each subject prior to drug initiation, 6 weeks after drug initiation, and 12 weeks after drug initiation.
Significant reductions in measures of disease activity and self-report of pain were found for the subjects who received an active drug, relative to those who received the placebo. The pain behavior scores produced by both groups of subjects remained relatively stable during the study.
The lack of change in pain behavior suggests that arthritis pain behavior may lack sensitivity to short-term changes accompanying drug therapy.