The American journal of emergency medicine
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Multicenter Study
Reliability and validity of a visual analog scale for acute abdominal pain in the ED.
The objective of the study was to assess the validity and reliability of the visual analog scale (VAS) in the measurement of acute abdominal pain, and to identify the minimum clinically significant difference in VAS scores among patients with acute abdominal pain. The study was undertaken in preparation for a randomized clinical trial of opioid use in acute abdominal pain. A prospective, observational cohort study of a convenience sample of patients presenting to 2 urban EDs with the chief complaint of acute abdominal pain was conducted. ⋯ VAS measures of acute abdominal pain are valid and reliable. The 95% CI surrounding the minimum clinically significant difference of approximately 16 mm overlaps with the 95% CI of minimum clinically significant difference of approximately 13 mm reported previously in traumatic and other types of acute pain. We conclude that the VAS is a methodologically sound instrument for quantitative assessment of acute abdominal pain and for detecting clinically important changes in such pain.