Test-Retest Reliability of QLU-C10D: Intraclass Correlation and Bland-Altman Analysis

To assess the test-retest reliability of the QLU-C10D questionnaire among 47 participants, we employed two methods: Intraclass correlation coefficient (ICC) analysis and Bland-Altman plot analysis. The ICC analysis yielded a value of 0.884 (95% CI 0.801-0.933), indicating a high degree of consistency in the test-retest measurements for QLU-C10D. This observation was further supported by the Bland-Altman plot (Fig. 4), which demonstrated that only 2.12% of the observations fell outside the limits of agreement, signifying a strong level of agreement between the repeated measurements.