SAS macros for point and interval estimation of area under the receiver operating characteristic curve for non-proportional and proportional hazards Weibull models.
Aims and objectives For prediction of risk of cardiovascular end points using survival models the proportional hazards assumption is often not met. Thus, non-proportional hazards models are more appropriate for developing risk prediction equations in such situations. However, computer program for ev...
| Published in: | Journal of Evaluation in Clinical Practice Vol. 16; no. 4; pp. 756 - 771 |
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| Main Authors: | , |
| Format: | equations & formulas research tables/charts Journal Article |
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Wiley-Blackwell
Aug2010
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=105057122&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 105057122 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 13561294 EV1 jtl: Journal of Evaluation in Clinical Practice issn: 13561294 maglogo: Y pubinfo: dt: Aug2010 vid: 16 iid: 4 pid: 480 pub: Wiley-Blackwell place: Malden, Massachusetts artinfo: ui: 105057122 2010717225 10.1111/j.1365-2753.2009.01190.x NLM20545799 105057122 ppf: 756 ppct: 15 formats: tig: atl: SAS macros for point and interval estimation of area under the receiver operating characteristic curve for non-proportional and proportional hazards Weibull models. aug: au: Mannan H Stevenson C affil: Senior Research Fellow, Unit Head, Department of Epidemiology & Preventive Medicine, Monash University, The Alfred, Melbourne, Victoria, Australia sug: subj: Computer Simulation Coronary Arteriosclerosis Data Analysis Software ROC Curve Confidence Intervals Human Validity ab: Aims and objectives For prediction of risk of cardiovascular end points using survival models the proportional hazards assumption is often not met. Thus, non-proportional hazards models are more appropriate for developing risk prediction equations in such situations. However, computer program for evaluating the prediction performance of such models has been rarely addressed. We therefore developed SAS macro programs for evaluating the discriminative ability of a non-proportional hazards Weibull model developed by Anderson (1991) and that of a proportional hazards Weibull model using the area under receiver operating characteristic (ROC) curve. Method Two SAS macro programs for non-proportional hazards Weibull model using Proc NLIN and Proc NLP respectively and model validation using area under ROC curve (with its confidence limits) were written with SAS IML language. A similar SAS macro for proportional hazards Weibull model was also written. Results The computer program was applied to data on coronary heart disease incidence for a Framingham population cohort. The five risk factors considered were current smoking, age, blood pressure, cholesterol and obesity. The predictive ability of the non-proportional hazard Weibull model was slightly higher than that of its proportional hazard counterpart. An advantage of SAS Proc NLP in terms of the example provided here is that it provides significance level for the parameter estimates whereas Proc NLIN does not. Conclusion The program is very useful for evaluating the predictive performance of non-proportional and proportional hazards Weibull models. pubtype: Academic Journal doctype: equations & formulas research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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