Evaluation of reliability, validity and sensitivity of the Chinese version of pruritus-specific quality of life instrument / 中华皮肤科杂志

ABSTRACT

Objective:To evaluate the reliability, validity and sensitivity of the Chinese version of pruritus-specific quality of life instrument (ItchyQoL) .Methods:Based on the English version of ItchyQoL, items of the Chinese version of ItchyQoL were determined after forward-backward translation and cultural adaption. Totally, 218 patients with pruritus caused by skin diseases were enrolled from Department of Dermatology, Peking University First Hospital from January to December 2019, and a questionnaire survey was conducted. At the time of enrollment and 2 weeks after enrollment, the Chinese version of ItchyQoL, dermatology life quality index (DLQI) and numerical rating scale (NRS) were used to evaluate the effect of pruritus on the quality of life of patients. Confirmatory factor was used to assess the structural validity of the Chinese version of ItchyQoL, and Cronbach′s α coefficient was used to estimate its internal consistency reliability. Spearman correlation coefficient was used to analyze correlations (convergent validity) of the Chinese version of ItchyQoL score with DLQI and NRS scores, and correlations (sensitivity) of changes in the Chinese version of ItchyQoL score with changes in DLQI and NRS scores.Results:The Chinese version of ItchyQoL contained a total of 22 items, including 3 dimensions, i.e., "symptoms", "functions" and "emotions", with the Cronbach′s α coefficients being 0.946, 0.883 and 0.953 respectively, suggesting excellent internal consistency. At 2 weeks after enrollment, the NRS score was strongly correlated with the total ItchyQoL score ( rs = 0.700, P < 0.01) , and moderately correlated with the subscores of "emotions", "functions" and "symptoms" ( rs = 0.452, 0.673, 0.692 respectively, all P < 0.01) ; the DLQI score was also strongly correlated with the total ItchyQoL score ( rs = 0.887, P < 0.01) and the subscores of "functions" and "symptoms" ( rs = 0.886, 0.750 respectively, both P < 0.01) , and moderately correlated with the "emotions" subscore ( rs = 0.674, P < 0.01) . Compared with the scores at the time of enrollment, the change in the total ItchyQoL score after 2 weeks was moderately correlated with the change in the NRS score ( rs = 0.642, P < 0.01) , and strongly correlated with the change in the DLQI score ( rs = 0.757, P < 0.01) ; the changes in "symptoms" and "functions" subscores were moderately correlated with the change in the NRS score ( rs = 0.648, 0.549 respectively, both P < 0.01) , while there was a weak correlation between the changes in "emotions" subscore and NRS score ( rs = 0.225, P < 0.01) ; the changes in "symptoms" and "functions" subscores were strongly correlated with the change in the DLQI score ( rs = 0.755, 0.703 respectively, both P < 0.01) , while the change in "emotions" subscore was moderately correlated with the change in the DLQI score ( rs = 0.401, P < 0.01) . Moreover, the total score of the Chinese version of ItchyQoL and subscores of "symptoms", "functions" and "emotions" all significantly differed among different NRS and DLQI score groups at 2 weeks after enrollment (all P < 0.05) . Conclusion:The Chinese version of ItchyQoL has good reliability and validity, and can be used to evaluate the quality of life of patients with pruritus caused by skin diseases in China.