Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory
Background & Aim: Multi-state models can help better understand the process of chronic diseases such as cancers. These models are influenced by assumptions like individual homogeneity. This study aimed to investigate the effect of lack of individual homogeneity assumption in multi-state...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Tehran University of Medical Sciences
2015-10-01
|
Series: | Journal of Biostatistics and Epidemiology |
Subjects: | |
Online Access: | https://jbe.tums.ac.ir/index.php/jbe/article/view/1 |
id |
doaj-8c0828907c284b93a9a0b11ddbed1f9c |
---|---|
record_format |
Article |
spelling |
doaj-8c0828907c284b93a9a0b11ddbed1f9c2020-12-06T04:10:32ZengTehran University of Medical SciencesJournal of Biostatistics and Epidemiology2383-41962383-420X2015-10-0113/4Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theoryAli Zare0Mahmood Mahmoodi1Kazem Mohammad2Hojjat Zeraati3Mostafa Hosseini4Kourosh Holakouie-Naieni5Department of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, IranDepartment of Epidemiology and Biostatistics, School of Health, Tehran University of Medical Sciences, Tehran, Iran Background & Aim: Multi-state models can help better understand the process of chronic diseases such as cancers. These models are influenced by assumptions like individual homogeneity. This study aimed to investigate the effect of lack of individual homogeneity assumption in multi-state models. Methods & Materials: To investigate the effect of lack of individual homogeneity assumption in multi-state models, tracking model as well as frailty factor with gamma distribution were used. Accordingly, without any simulation and only based on asymptotic theory, the bias of mean transition rate which is among the basic parameters of the multi-state models was studied. Results: Analysis of the effect of individual homogeneity assumption misspecification revealed that for different number of follow-ups as well as censoring time, the mean transition rate and its variance were underestimated. In addition, if there is a lot of heterogeneity in reality and if the individual homogeneous multi-state model is fitted, a significant bias will exist in the estimated mean transition rate and its variance. The results of this study also showed that the intensity of bias increases with an increase in the degree of heterogeneity. But with an increase in the number of follow-ups, the intensity of bias decreases, to some extent. Conclusion: Disregarding individual homogeneity assumption in a heterogeneous population causes bias in the estimation of multi-state model parameters and with an increase in the degree of heterogeneity, the intensity of bias will increase too. https://jbe.tums.ac.ir/index.php/jbe/article/view/1asymptotic theoryfrailtyindividual homogeneitygamma distributionmisspecificationmulti-state model |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ali Zare Mahmood Mahmoodi Kazem Mohammad Hojjat Zeraati Mostafa Hosseini Kourosh Holakouie-Naieni |
spellingShingle |
Ali Zare Mahmood Mahmoodi Kazem Mohammad Hojjat Zeraati Mostafa Hosseini Kourosh Holakouie-Naieni Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory Journal of Biostatistics and Epidemiology asymptotic theory frailty individual homogeneity gamma distribution misspecification multi-state model |
author_facet |
Ali Zare Mahmood Mahmoodi Kazem Mohammad Hojjat Zeraati Mostafa Hosseini Kourosh Holakouie-Naieni |
author_sort |
Ali Zare |
title |
Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
title_short |
Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
title_full |
Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
title_fullStr |
Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
title_full_unstemmed |
Assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
title_sort |
assessing misspecification of individual homogeneity assumption in multi-state models based on asymptotic theory |
publisher |
Tehran University of Medical Sciences |
series |
Journal of Biostatistics and Epidemiology |
issn |
2383-4196 2383-420X |
publishDate |
2015-10-01 |
description |
Background & Aim: Multi-state models can help better understand the process of chronic diseases such as cancers. These models are influenced by assumptions like individual homogeneity. This study aimed to investigate the effect of lack of individual homogeneity assumption in multi-state models.
Methods & Materials: To investigate the effect of lack of individual homogeneity assumption in multi-state models, tracking model as well as frailty factor with gamma distribution were used. Accordingly, without any simulation and only based on asymptotic theory, the bias of mean transition rate which is among the basic parameters of the multi-state models was studied.
Results: Analysis of the effect of individual homogeneity assumption misspecification revealed that for different number of follow-ups as well as censoring time, the mean transition rate and its variance were underestimated. In addition, if there is a lot of heterogeneity in reality and if the individual homogeneous multi-state model is fitted, a significant bias will exist in the estimated mean transition rate and its variance. The results of this study also showed that the intensity of bias increases with an increase in the degree of heterogeneity. But with an increase in the number of follow-ups, the intensity of bias decreases, to some extent.
Conclusion: Disregarding individual homogeneity assumption in a heterogeneous population causes bias in the estimation of multi-state model parameters and with an increase in the degree of heterogeneity, the intensity of bias will increase too.
|
topic |
asymptotic theory frailty individual homogeneity gamma distribution misspecification multi-state model |
url |
https://jbe.tums.ac.ir/index.php/jbe/article/view/1 |
work_keys_str_mv |
AT alizare assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory AT mahmoodmahmoodi assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory AT kazemmohammad assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory AT hojjatzeraati assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory AT mostafahosseini assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory AT kouroshholakouienaieni assessingmisspecificationofindividualhomogeneityassumptioninmultistatemodelsbasedonasymptotictheory |
_version_ |
1724399458367569920 |