Replication and validation of higher order models demonstrated that a summary score for the EORTC QLQ-C30 is robust
Johannes M Giesinger, Jacobien M Kieffer, Peter M Fayers, Mogens Groenvold, Morten Aa Petersen, Neil W Scott, Mirjam A G Sprangers, Galina Velikova, Neil K Aaronson, EORTC Quality of Life Group, M King, S Leutenegger, N Spry, E Greimel, B Holzner, A Bottomley, C Coens, K West, G de Castro, C de Souza, A Bezjak, M Whitehead, M Groenvold, M Klee, M Petersen, A Bredart, T Conroy, C Rodary, M Berend, B Bestmann, M Koller, O Krauß, T Kuchler, B Malchow, R Schwarz, K Mystakidou, A Montazeri, C Brunelli, M Tamburini, T Matsuoka, H Zhao, N Aaronson, A de Graeff, C Gundy, R de Leeuw, M Muller, M Sprangers, K Bjordal, E Brenne, M Hjermstad, M Jordhøy, P Klepstad, S Sundstrøm, F Wisløff, Y B Cheung, S B Tan, J Thumboo, H B Wong, Y H Yun, J Arraras, H Jayasekara, L Rajapakse, M Ahlner-Elmqvist, P Ballabeni, J Bernhard, W-C Chie, U Abacioglu, J Blazeby, J Bruce, A Davies, P Fayers, L Friend, Z Krukowski, T Massett, J Nicklin, J Ramage, N Scott, A Smyth-Cull, T Young, D Cella, D-L Esseltine, C Gotay, I Pagano, Johannes M Giesinger, Jacobien M Kieffer, Peter M Fayers, Mogens Groenvold, Morten Aa Petersen, Neil W Scott, Mirjam A G Sprangers, Galina Velikova, Neil K Aaronson, EORTC Quality of Life Group, M King, S Leutenegger, N Spry, E Greimel, B Holzner, A Bottomley, C Coens, K West, G de Castro, C de Souza, A Bezjak, M Whitehead, M Groenvold, M Klee, M Petersen, A Bredart, T Conroy, C Rodary, M Berend, B Bestmann, M Koller, O Krauß, T Kuchler, B Malchow, R Schwarz, K Mystakidou, A Montazeri, C Brunelli, M Tamburini, T Matsuoka, H Zhao, N Aaronson, A de Graeff, C Gundy, R de Leeuw, M Muller, M Sprangers, K Bjordal, E Brenne, M Hjermstad, M Jordhøy, P Klepstad, S Sundstrøm, F Wisløff, Y B Cheung, S B Tan, J Thumboo, H B Wong, Y H Yun, J Arraras, H Jayasekara, L Rajapakse, M Ahlner-Elmqvist, P Ballabeni, J Bernhard, W-C Chie, U Abacioglu, J Blazeby, J Bruce, A Davies, P Fayers, L Friend, Z Krukowski, T Massett, J Nicklin, J Ramage, N Scott, A Smyth-Cull, T Young, D Cella, D-L Esseltine, C Gotay, I Pagano
Abstract
Objective: To further evaluate the higher order measurement structure of the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30), with the aim of generating a summary score.
Study design and setting: Using pretreatment QLQ-C30 data (N = 3,282), we conducted confirmatory factor analyses to test seven previously evaluated higher order models. We compared the summary score(s) derived from the best performing higher order model with the original QLQ-C30 scale scores, using tumor stage, performance status, and change over time (N = 244) as grouping variables.
Results: Although all models showed acceptable fit, we continued in the interest of parsimony with known-groups validity and responsiveness analyses using a summary score derived from the single higher order factor model. The validity and responsiveness of this QLQ-C30 summary score was equal to, and in many cases superior to the original, underlying QLQ-C30 scale scores.
Conclusion: Our results provide empirical support for a measurement model for the QLQ-C30 yielding a single summary score. The availability of this summary score can avoid problems with potential type I errors that arise because of multiple testing when making comparisons based on the 15 outcomes generated by this questionnaire and may reduce sample size requirements for health-related quality of life studies using the QLQ-C30 questionnaire when an overall summary score is a relevant primary outcome.
Keywords: Confirmatory factor analysis; EORTC QLQ-C30; Health-related quality of life; Higher order factor scores; Measurement model; Questionnaires.
Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
Source: PubMed