Revised Chinese Version of Mishel Uncertainty in Illness Scale: Development, Reliability and Validity

Abstract

Objective: To develop the Revised Chinese Version of Mishel Uncertainty in Illness Scale (RC-MUIS), and test its reliability and validity in a sample of Chinese patients with cancer.

Methods: The original MUIS was translated into Chinese and revised, then the initial RC-MUIS was developed. Then, the psychometric properties of the initial RC-MUIS were tested in 550 conveniently sampled patients with cancer who received treatment from the First Affiliated Hospital of Guangzhou University of Chinese Medicine, Sun Yat-sen University Cancer Center, Guangdong Provincial Hospital of Chinese Medicine from July 2015 to April 2016. The participants were also surveyed by a self-developed Baseline Characteristics Questionnaire, Chinese version of Zung Self-Rating Anxiety Scale (C-SAS), Chinese version of Zung Self-Rating Depression Scale (C-SDS), and Chinese version of Strategies Used by People to Promote Health (C-SUPPH) for testing the convergent validity of the initial RC-MUIS. Two weeks later, the initial RC-MUIS was re-tested in 50 patients randomly selected from the responsive participants (totaled 470) in the first test by an Excel-based program. After that, we conducted item analysis, reliability and validity assessment of the initial RC-MUIS, then developed the final RC-MUIS, and determined its cutoff value.

Results: The final RC-MUIS includes three factors (ambiguity, lack of clarity and unpredictability) covering 20 items, which were extracted by factor analysis, explaining 57.23% of the total variance. The CVI of items ranged from 0.73-1.00. KMO=0.810 and Bartlett’s χ ²=871.55, P<0.001. Confirmatory factor analysis showed root mean square error of approximation (RMSEA)=0.037, comparative fit index (CFI)=0.905, goodness-of-fit index (GFI)=0.936, adjusted goodness-of-fit index (AGFI)= 0.911, standardized root mean square residual (SRMR)=0.052. RC-MUIS and its factors were positively associated with C-SAS and C-SDS and their corresponding factors in terms of score (P<0.05), but were negatively associated with C-SUPPH and its factors (P<0.05). The Cronbach’s α and test-retest reliability of RC-MUIS was 0.825 and 0.836, respectively. The cut-off value, sensitivity and specificity of RC-MUIS was 60.5, 0.715 and 0.759, respectively.

Conclusion: The RC-MUIS, being reliable, valid and easy to use, is suitable to be adapted by clinical settings as a screening tool to recognize Chinese cancer patients with high-risk psychological problems.