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

M Lauriola¹, R Murri³, M Massella⁴, M Mirra⁴, S Donnini⁴, V Fragola⁴, J Ivanovic⁵, M Pavoni⁶, G Mancini², R Bucciardini⁴

¹Department of Social and Developmental Psychology, ²Department of Infectious and Tropical Diseases, University of Rome “La Sapienza”, Rome, Italy; ³Catholic University of “Sacro Cuore”, Rome, Italy; ⁴Istituto Superiore di Sanità, Rome, Italy; ⁵National Institute for Infectious Diseases Lazzaro Spallanzani, Rome, Italy; ⁶Ospedale Civile Santa Maria delle Croci, Ravenna, Italy

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 secondorder 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.

Keywords: confirmatory factor analysis, HRQoL, patient-reported outcomes