Amaia Bilbao-Gonz\u00e1lez, Marta Gonz\u00e1lez-S\u00e1enz de Tejada, Montse Ferrer, Yolanda Ramallo-Fari\u00f1a, Miguel Paja-Fano, Carlos Garc\u00eda-Forero, Daniela Mestre, I\u00f1igo Gorostiza-Hormaetxe<\/p>\n
ABSTRACT<\/strong><\/p>\n Background<\/strong><\/p>\n The EQ-5D-5L five-dimensional instrument, is one of the most widely used generic preference-based questionnaires to measure health-related quality of life and to estimate utility indices for use in economic evaluation. This study aimed to assess the psychometric properties of the Spanish EQ-5D-5L questionnaire in patients with Diabetes Mellitus (DM) assessing reliability, validity, and item-level properties such as item functioning.<\/p>\n Methodology<\/strong><\/p>\n We included 133 patients with DM who completed the EQ-5D-5L, the Audit on Diabetes-Dependent Quality of Life (ADDQoL), the Hospital Anxiety and Depression Scale (HADS), one question about general health and sociodemographic, and clinical data. The reliability was assessed by Cronbach’s alpha, and the item functioning by the item response theory (IRT). Convergent validity was tested using the Spearman correlation coefficient between EQ-5D-5L, ADDQoL, HADS and the general health question. We examined known-groups validity by comparing the EQ-5D-5L scores between subgroups defined by age, gender, BMI, regular physical activity, disease duration, glycemic control by glycosylated blood hemoglobin (HbA1c) (%), type of DM, general health and anxiety and depression level using t-test, ANOVA, Wilcoxon or Kruskal-Wallis tests.<\/p>\n