Pain and therapy
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Pain, and particularly chronic pain, is a difficult outcome to measure due to its subjective and multidimensional nature. The Institute of Medicine estimates that 100 million Americans have chronic pain with a cost exceeding half a trillion dollars per year. There is a pressing need to identify appropriate outcome measures to better select and evaluate treatment modalities for these patients. ⋯ The authors then review frequently employed tools for measuring pain outcomes ranging from univariable and single domain scales to multidimensional instruments. A discussion of possible behavioral and objective measures is pursued, as well as measures of statistical and treatment efficacy. The article closes with a review of recent and ongoing efforts to validate and standardize pain outcome measures and suggests directions for future clinical and research assessment.