Article (Scientific journals)
Multicollinearity in prognostic factor analyses using the EORTC QLQ-C30: identification and impact on model selection
Van Steen, Kristel; Curran, D.; Kramer, J. et al.
2002In Statistics in Medicine, 21 (24), p. 3865-3884
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Keywords :
multicollinearity; prognostic factor analysis; quality of life data; bootstrap
Abstract :
[en] Clinical and quality of life (QL) variables from an EORTC clinical trial of first line chemotherapy in advanced breast cancer were used in a prognostic factor analysis of survival and response to chemotherapy. For response, different final multivariate models were obtained from forward and backward selection methods, suggesting a disconcerting instability. Quality of life was measured using the EORTC QLQ-C30 questionnaire completed by patients. Subscales on the questionnaire are known to be highly correlated, and therefore it was hypothesized that multicollinearity contributed to model instability. A correlation matrix indicated that global QL was highly correlated with 7 out of 11 variables. In a first attempt to explore multicollinearity, we used global QL as dependent variable in a regression model with other QL subscales as predictors. Afterwards, standard diagnostic tests for multicollinearity were performed. An exploratory principal components analysis and factor analysis of the QL subscales identified at most three important components and indicated that inclusion of global QL made minimal difference to the loadings on each component. suggesting that it is redundant in the model, In a second approach, we advocate a bootstrap technique to assess the stability of the models. Based on these analyses and since global QL exacerbates problems of multicollinearity, we therefore recommend that global QL be excluded from prognostic factor analyses using the QLQ-C30. The prognostic factor analysis was rerun without global QL in the model, and selected the same significant prognostic factors as before. Copyright (C) 2002 John Wiley Sons, Ltd.
Disciplines :
Public health, health care sciences & services
Laboratory medicine & medical technology
Mathematics
Life sciences: Multidisciplinary, general & others
Author, co-author :
Van Steen, Kristel  ;  Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Bioinformatique
Curran, D.
Kramer, J.
Molenberghs, G.
Van Vreckem, A.
Bottomley, A.
Sylvester, R.
Language :
English
Title :
Multicollinearity in prognostic factor analyses using the EORTC QLQ-C30: identification and impact on model selection
Publication date :
2002
Journal title :
Statistics in Medicine
ISSN :
0277-6715
eISSN :
1097-0258
Publisher :
John Wiley & Sons, Hoboken, United States - New Jersey
Volume :
21
Issue :
24
Pages :
3865-3884
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 24 May 2010

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