Psychometric properties of the Audit of Diabetes-Dependent Quality of Life (ADDQoL) in a population-based sample of Polish adults with type 1 and 2 diabetes

BACKGROUND The aim of the present paper was the assessment of the psychometric properties of the Polish language version of the Audit of Diabetes-Dependent Quality of Life (ADDQoL) questionnaire applied in Poland among patients with type 1 (T1DM) or type 2 diabetes (T2DM). METHODS The studies were carried out among 330 patients with diabetes including 115 with T1DM and 215 with T2DM. In all the patients the level of the quality of life was investigated using the Polish language version of the ADDQoL and the psychometric properties were determined taking into consideration internal consistency, the factor loading and intraclass correlations. RESULTS It was demonstrated that the values of internal consistency determining the reliability of the Polish language version of the ADDQoL for the overall Cronbach's alfa coefficient were 0.92 in the studied patients with T1DM and 0.93 in the studied patients with T2DM and the values of the loading factor were respectively 0.39-0.79 and 0.35-0.81. In the study of the correlation between the components of the ADDQoL the correlation coefficients proved to be highly statistically significant: in patients with T1DM r = 0.46-0.74 and in patients with T2DM - r = 0.42-0.80. CONCLUSION The Polish language version of the ADDQoL is a reliable tool useful for the assessment of the level of the quality of life of adult patients with T1DM or T2DM in Poland and is recommended to be used among Polish-speaking patients with diabetes.