Clinical significance of reported changes in pain severity.

STUDY OBJECTIVE: To determine the amount of change in pain severity, as measured by a visual analog scale, that constitutes a minimum clinically significant difference. METHODS: Patients 18 years of age or older who presented with acute pain resulting from trauma were enrolled in this prospective, descriptive study. The setting was an urban county hospital emergency department with a Level 1 trauma center. In the course of a brief interview, patients were asked to indicate their current pain severity with a single mark through a standard 100-mm visual analog scale. At intervals of 20 minutes for the next 2 hours, patients were asked to repeat this measurement and, in addition, to contrast their present pain severity with that at the time of the previous measurement. They were to indicate whether they had "much less," "a little less," "about the same," "a little more," or "much more" pain. All contrasts were made without reference to prior visual analog scale measurements. A maximum of six measurements of pain change were recorded per patient. Measurements ended when the patient left the ED or when the patient reported a pain score of zero. The minimum clinically significant change in visual analog scale pain score was defined as the mean difference between current and preceding visual analog scale scores when the subject noted a little less or a little more pain. RESULTS: Forty-eight subjects were enrolled, and 248 pain contrasts were recorded. Of these contrasts, 41 were rated as a little less and 39 as a little more pain. The mean difference between current and preceding visual analog scale scores in these 80 contrasts was 13 mm (95% confidence interval, 10 to 17 mm). CONCLUSION: The minimum clinically significant change in patient pain severity measured with a 100-mm visual analog scale was 13 mm. Studies of pain experience that report less than a 13-mm change in pain severity, although statistically significant, may have no clinical importance.

The minimum clinically important difference in physician-assigned visual analog pain scores.

OBJECTIVE: To determine the minimum clinically important difference in physician-assigned visual analog scale (VAS) pain scores. METHODS: Physicians attending emergency medicine didactic conferences were enrolled in this descriptive study. The subjects sequentially reviewed 11 written scenarios describing patients in moderate to severe pain. The subjects rated their perceptions of each patient's pain on a 100-mm VAS, then contrasted this pain with that of the previous patient scenario. For these contrasts, the subjects chose one of five responses: "much less," "a little less," "about the same," "a little more," or "much more" pain. The minimum clinically important difference was defined as the difference between scores for scenario pairs in which one patient's pain was rated "a little less" or "a little more" severe. RESULTS: There were 230 comparisons by 23 health professionals. Of these, 64 were judged "a little less," and 56 "a little more," painful. These 120 comparisons, with their pain score differences, were used to determine the minimum clinically important difference. Pain judged to be "a little less" or "a little more" severe was associated with a mean difference in VAS scores of 18 mm (95% CI 16-20 mm), corresponding to a decrement of 23% (95% CI 20-26%) from the more painful scenario. CONCLUSIONS: Pain research outcomes involving a < 18-mm difference, or a 23% decrement in physician-assigned VAS pain scores, although statistically significant, may have little clinical importance.

Chest pain associated with cocaine: an assessment of prevalence in suburban and urban emergency departments.

STUDY OBJECTIVE: Chest pain and myocardial infarction following the use of cocaine have been well documented. We assessed the prevalence of cocaine use in patients who presented to the emergency department with chest pain of possibly ischemic origin. DESIGN: During times of research assistant availability, consecutive adults with the chief complaint of chest pain unexplained by trauma or radiographic abnormality were questioned about cocaine use in the preceding week. Urine was tested for the presence of cocaine or cocaine metabolites with a highly accurate bedside urine test kit (specificity, 100%; sensitivity 98%). Anonymous unlinked data-collection methods were used. Therefore we could not determine whether the patients who used cocaine had sustained myocardial infarctions. SETTING: One suburban and three urban EDs. RESULTS: We enrolled 359 patients with a mean age of 51 years, 8% of whom sustained myocardial infarctions. Sixty patients (17%) had cocaine or cocaine metabolites in urine. The likelihood of testing positive for cocaine varied by age group: 18 to 30 years, 29%; 31 to 40 years, 48%; 41 to 50 years, 18%; 51 to 60 years, 3%; 61 years or older, 0% (P < .0001). Of the 60 patients who tested positive for cocaine, only 43 (72%) admitted recent use. CONCLUSION: Many ED patients with chest pain have recently used cocaine. Because the recent use of cocaine is not uncommon in patients with chest pain up to 60 years old, such patients should be questioned about cocaine use. When treatment or disposition may be altered, consideration should be given to objective assessment of cocaine use because patient self-report does not appear reliable.