Psychometric properties and confirmatory factor analysis of the CASP-19, a measure of quality of life in early old age: the HAPIEE study

Objectives: The aim was to assess the reliability and validity of the quality of life (QoL) instrument CASP-19, and three shorter versions of CASP-12 in large population sample of older adults from the HAPIEE (Health, Alcohol, and Psychosocial factors In Eastern Europe) study. Methods: From the Czech Republic, Russia, and Poland, 13,210 HAPIEE participants aged 50 or older completed the retirement questionnaire including CASP-19 at baseline. Three shorter 12-item versions were also derived from original 19-item instrument. Psychometric validation used confirmatory factor analysis, Cronbach's alpha, Pearson's correlation, and construct validity. Results: The second-order four-factor model of CASP-19 did not provide a good fit to the data. Two-factor CASP-12v.3 including residual covariances for negative items to account for the method effect of negative items had the best fit to the data in all countries (CFI = 0.98, TLI = 0.97, RMSEA = 0.05, and WRMR = 1.65 in the Czech Republic; 0.96, 0.94, 0.07, and 2.70 in Poland; and 0.93, 0.90, 0.08, and 3.04 in Russia). Goodness-of-fit indices for the two-factor structure were substantially better than second-order models. Conclusions: This large population-based study is the first validation study of CASP scale in Central and Eastern Europe (CEE), which includes a general population sample in Russia, Poland, and the Czech Republic. The results of this study have demonstrated that the CASP-12v.3 is a valid and reliable tool for assessing QoL among adults aged 50 years or older. This version of CASP is recommended for use in future studies investigating QoL in the CEE populations.