Psychometric properties of the World Health Organisation quality of life questionnaire (WHOQOL-100) in diabetic patients in Croatia.

UNLABELLED: The aim of the study was to analyse psychometric properties of the WHOQOL-100, a multidimensionally conceptualised, generic, 100-item quality of life (QoL) instrument in a pilot sample of 63 type 2 diabetic patients (age 60.4 (10.1) years), 55% women, disease duration 10.2 (6.2) years, education 10 (5.2) years, 78% married. While covering the subjective perception and evaluation of the overall QoL and general health, as well as four broad domains (physical health, psychological state, social relationships and environment), the instrument may be useful in integrating the individual perception of the QoL. The properties tested referred to reliability, validity in discriminating patients with different disease characteristics, and responsiveness to change.
METHODS: Reliability was determined by Cronbach's alpha coefficients of internal consistency. Discriminant validity was determined by comparing the groups of patients with poor and satisfactory glycaemic control, the first group being switched to insulin therapy (intervention group) and the second (comparison group) remaining on oral therapy (35 and 28 patients respectively). Responsiveness to change was determined by comparing the two groups after a 2-month follow-up period.
RESULTS: The obtained alpha coefficients were 0.95 for the physical domain, 0.89 for the psychological domain, 0.76 for the social relationships domain, and 0.92 for the domain referring to environment. The interventional and comparison groups rated their QoL differently, primarily in the physical and psychological domains (P<0.01; P<0.05). After a 2-month follow-up period, the intervention group was improved in some QoL determinants (psychological domain), while no differences were found in the control group.
CONCLUSION: Relying on the data obtained from the groups of diabetic patients in Croatia, the WHOQOL-100 can be considered as acceptably reliable and valid instrument for the QoL assessment in this particular population of health care users.