Yale University

Using multiple daily pain ratings to improve reliability and assay sensitivity: How many is enough?

TitleUsing multiple daily pain ratings to improve reliability and assay sensitivity: How many is enough?
Publication TypeJournal Article
Year of Publication2014
AuthorsHeapy, Alicia, James Dziura, Eugenia Buta, Joseph Goulet, Joseph F. Kulas, and Robert D. Kerns
JournalThe journal of pain : official journal of the American Pain Society
Date Published2014 Oct 2
AbstractThe Initiative for Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) has reported diminished assay sensitivity in pain treatment trials and recommended investigation of the causes. Specific recommendations included examination of outcome measure reliability and lengthening the baseline measurement period to allow more measurements to be collected. This secondary data analysis evaluated the minimum number of daily pain intensity ratings required to obtain a reliability of at least 0.90 and whether a composite of this smaller number of ratings was interchangeable with the composite of all ratings. Veterans Affairs (VA) medical center patients made 14 daily calls to an automated telephone system to report their average daily pain intensity rating. A single daily rating produced less than adequate reliability (ICC=0.65), but a composite of the average of five ratings resulted in reliability above 0.90. A Bland-Altman analysis revealed that the differences between a five-day composite and the composite of all ratings were small (mean 0.09 points, SD = 0.45; 95% confidence interval = -0.05 to 0.23) and below the threshold for a clinically meaningful difference, indicating the two measurements are interchangeable. Our results support IMMPACT recommendations for improving assay sensitivity by collecting a multi-day baseline of pain intensity ratings.
Alternate JournalJ Pain

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