Development and validation of the systemic lupus erythematous scale amongst the system of quality of life instruments for chronic diseases QLICD-SLE (V2.0)

Abstract

Abstract Objective: The present study aims to develop a quality of life scale for systemic lupus erythematosus (SLE) patients with Chinese cultural background. As such, its reliability, validity and responsiveness are evaluated. Methods: The programmatic decision-making method of issue group and core group was adopted, and the preliminary selection, evaluation and modification of items were made through the combination of qualitative interview and quantitative investigation and analysis to form a preliminary scale. 428 patients with SLE participated in the measurement of this scale. Qualitative, item domain correlation, multidimensional scaling and factor analysis were used to measure the validity of the scale. Pearson’s correlation and Cronbach’s alpha coefficients were used to evaluate the reliability of the scale. The responsiveness evaluation method of the scale in the present study primarily used the paired T-test for the first and second measurements (before and after treatment) of all areas of the scale, aspects of specific modules and total scores of the scale in patients with SLE, and to calculate the standardised response mean (SRM). Results: Correlation and factor analyses demonstrated good structural validity and reasonable reactivity. The correlation of each item with its domain is greater than that with other fields, and the correlation coefficient r value is more than 0.50. Using SF-36 as calibration, the correlation between QLICD-SLE and various fields of SF-36 was calculated, and the results were 0.55-0.70.The retest correlation coefficients were all greater than 0.71 and Cronbach’s alpha coefficients of two measurements in each domain are greater than or equal to 0.75. T-test results showed that there were statistical differences in energy and discomfort, social function, interpersonal communication, skin and mucosal symptoms and respiratory/circulation symptoms (P<0.05). Conclusion: The QLICD-SLE V2.0 appears to be a valid and reliable instrument to measure QOL in SLE patients.