Italian translation, cultural adaptation and validation of the PedsQL™ 3.0 Diabetes Module questionnaire in children with type 1 diabetes and their parents

Background: The PedsQL™3.0 Diabetes Module is a widely used instrument to measure the disease-specific health-related quality of life summary measures in children and adolescents with type 1 diabetes. After cultural adaptation, we confirmed reliability and validity of PedsQL™3.0 Diabetes Module in its Italian version.Methods: Participants were 169 Italian children and adolescents with type 1 diabetes aged 5-18 years and 100 parents. Reliability was determined by internal consistency using Cronbach's coefficient alpha, and test-retest reliability by intra-class correlation coefficient (ICC). Validity was assessed through factor validity examined by exploratory factor analysis, and discriminant validity examined through multitrait/multi-item scaling analysis. Discriminant validity with respect to dichotomous patients' characteristics at baseline was also examined through a multivariate analysis on the summary measures using the Wilks' Lambda test.Results: Data completeness was optimal. Item internal consistency was satisfied at 89% for the child self-report scales and at 100% for the parents' proxy-report scales. Most diabetes module scales was acceptable for group comparisons. Discriminant validity was satisfied for 71% of children and adolescents and for 82% of parents. A ≥70% Cronbach's α coefficient was found for the summary measures of both reports. For the test-retest reliability, the ICC coefficients ranged from 0.66 (i.e., the Worry scale) to 0.82 for the other scales of the child self-report. The ICC coefficients were ≥0.87 for all the parents' proxy-report scales. Factor analysis showed that the PedsQL™3.0 Diabetes Module for child self-report could be summarized in 10 components, which explained the 62% of the variance. For the parent proxy-report the statistical analysis selected 9 factors, which explained about 68% of variance. The external discriminant validity of the PedsQL™3.0 Diabetes Module summary measures were compared across gender, age, time since diagnosis and HbA1c mean cut off values. Significant differences in the " Treatment adherence" scale and in the " Communication" scale were observed across age, and by time since diagnosis.Conclusions: The results show the reliability and validity of the Italian translation of the PedsQL™3.0 Diabetes Module, supporting therefore its use as an outcome measure for diabetes cross-national clinical trials and research.