Cross cultural adaptation of the Injection Drug User Quality Of Life Scale (IDUQOL) in Spanish drug dependent population, with or without injectable consumption: Drug User Quality of Life Scale-Spanish (DUQOL-Spanish).

The Injection Drug User Quality of life Scale (IDUQOL) measures the unique and individual circumstances that determine the quality of life of injection drug users. This paper reports the psychometric properties of the Spanish version, for drug dependent persons with or without injectable consumption using a revised instrument: Drug user Quality of Life Scale-Spanish (DUQOL-Spanish). We studied 169 outpatients in 9 Spanish drug treatment centers. Factor analysis, internal consistency, test-retest reliability and criterion-related validity were assessed. The results show the essential unidimensionality of the scale, which supports the use of a total score. Both internal consistency (Cronbach's alpha: 0.86), and test-retest reliability (r=0.79) of the total score were high. Criterion-related validity supports the interpretation of the DUQOL-Spanish total score as measuring a construct consistent with quality of life. This study suggests that the DUQOL-Spanish is a valid instrument to measure subjective quality of life in Spanish drug users, and allows the identification of life areas that are considered by the patient important to change in order to improve their quality of life.