摘要
Background and Aims:A visual analogue score (VAS),based on application of a visual analogue scale,has been widely used to assess pruritus in clinical studies of patients with cholestatic liver disease.A VAS is a numerical score of the severity of the perception of pruritus,and,hence,is inherently subjective.The objective of this study was to assessthe reliability of a VAS as an index of pruritus in cholestatic patients.Methods:In 8 patients with chronic pruritus due to primary biliary cholangitis,values for a VAS of pruritus were compared with corresponding measurements of scratching activity,which were generated by a monitoring system specifically designed to quantitate this activity.The relationship between individual values for the VAS and corresponding values for scratching activity during a specific interval immediately preceding the recording of the VAS was examined by determining the Spearman's rank correlation coefficient.Results:The mean Spearman's rank correlation coefficient between individual values for the VAS and corresponding mean values for scratching activity was 0.072;the range of these coefficients was-0.04 to 0.26.A VAS of pruritus is an unreliable index of scratching activity,and,hence,of the pathophysiological process responsible for the pruritus of cholestasis.Conclusion:It is concluded that the use of a VAS as a primary quantitative endpoint in trials of the efficacy of potential therapies for the pruritus of cholestasis may be inappropriate.
Background and Aims:A visual analogue score (VAS),based on application of a visual analogue scale,has been widely used to assess pruritus in clinical studies of patients with cholestatic liver disease.A VAS is a numerical score of the severity of the perception of pruritus,and,hence,is inherently subjective.The objective of this study was to assessthe reliability of a VAS as an index of pruritus in cholestatic patients.Methods:In 8 patients with chronic pruritus due to primary biliary cholangitis,values for a VAS of pruritus were compared with corresponding measurements of scratching activity,which were generated by a monitoring system specifically designed to quantitate this activity.The relationship between individual values for the VAS and corresponding values for scratching activity during a specific interval immediately preceding the recording of the VAS was examined by determining the Spearman's rank correlation coefficient.Results:The mean Spearman's rank correlation coefficient between individual values for the VAS and corresponding mean values for scratching activity was 0.072;the range of these coefficients was-0.04 to 0.26.A VAS of pruritus is an unreliable index of scratching activity,and,hence,of the pathophysiological process responsible for the pruritus of cholestasis.Conclusion:It is concluded that the use of a VAS as a primary quantitative endpoint in trials of the efficacy of potential therapies for the pruritus of cholestasis may be inappropriate.
