A factor analytic study of the Italian National Institute of Health Quality of Life – Core Evaluation Form (ISSQoL-CEF)

OBJECTIVES The Italian National Institute of Health Quality of Life - Core Evaluation Form (ISSQoL-CEF) is a specific questionnaire measuring health-related quality of life for human immunodeficiency virus-infected people in the era of highly active antiretroviral therapy. The main goal of this study was to examine the construct validity of this questionnaire by confirmation of its hypothesized dimensional structure. METHODS Baseline quality of life data from four clinical studies were collected and a confirmatory factor analysis of the ISSQoL-CEF items was carried out. Both first-order and second-order factor models were tested: Model 1 with nine correlated first-order factors; Model 2 with three correlated second-order factors (Physical, Mental, and Social Health); Model 3 with two correlated second-order factors (Physical and Mental/Social Health); Model 4 with only one second-order factor (General Health). RESULTS A total of 261 patients were surveyed. Model 1 had a good fit to the data. Model 2 had an acceptable fit to the data and it was the best of all hierarchical models. However, Model 2 fitted the data worse than Model 1. CONCLUSIONS The findings of in this study, consistent with the results of previous study, pointed out the construct validity of the ISSQoL-CEF.