Comparison of the sensitivity to change of long and short form pain measures

Our objective was to assess the sensitivity to change over time of three methods of assessing pain. We conducted a comparison of the sensitivity to change of three pain assessment measures in a double blind, double dummy parallel group study evaluating the efficacy of one of two doses of oral bromfenac and one of two doses of sublingual buprenorphine. Our subject pool consisted of 75 patients following general surgical and orthopaedic procedures. Pain intensity was measured by the affective, sensory and evaluative dimensions of the McGill Pain Questionnaire together with total score and word score, a 10 cm Visual Analogue Scale and by a four word scale. Effect size calculations indicated considerable variation in the sensitivity of the instruments to change. However, despite variation in the size of effect indicated by different measures, there was consistent agreement as to the most effective treatment regimen. This study suggests that simple measures of pain are sensitive to change and are worthwhile indicators of the impact of an intervention upon acute pain, although some care is needed in interpreting results from such instruments. More complex forms of assessment, such as the calculation of the MPQ sub-scales may not add anything to such data.