Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.

Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.

<h4>Introduction</h4>The Irish ALS register is a valuable resource for examining survival factors in Irish ALS patients. Cox regression has become the default tool for survival analysis, but recently new classes of flexible parametric survival analysis tools known as Royston-Parmar model...

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Autores principales: James Rooney, Susan Byrne, Mark Heverin, Bernie Corr, Marwa Elamin, Anthony Staines, Ben Goldacre, Orla Hardiman
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Publicado: Public Library of Science (PLoS) 2013
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spelling oai:doaj.org-article:595c479a6df84ac795cde150118448582021-11-18T08:53:07ZSurvival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.1932-620310.1371/journal.pone.0074733https://doaj.org/article/595c479a6df84ac795cde150118448582013-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24098664/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Introduction</h4>The Irish ALS register is a valuable resource for examining survival factors in Irish ALS patients. Cox regression has become the default tool for survival analysis, but recently new classes of flexible parametric survival analysis tools known as Royston-Parmar models have become available.<h4>Methods</h4>We employed Cox proportional hazards and Royston-Parmar flexible parametric modeling to examine factors affecting survival in Irish ALS patients. We further examined the effect of choice of timescale on Cox models and the proportional hazards assumption, and extended both Cox and Royston-Parmar models with time varying components.<h4>Results</h4>On comparison of models we chose a Royston-Parmar proportional hazards model without time varying covariates as the best fit. Using this model we confirmed the association of known survival markers in ALS including age at diagnosis (Hazard Ratio (HR) 1.34 per 10 year increase; 95% CI 1.26-1.42), diagnostic delay (HR 0.96 per 12 weeks delay; 95% CI 0.94-0.97), Definite ALS (HR 1.47 95% CI 1.17-1.84), bulbar onset disease (HR 1.58 95% CI 1.33-1.87), riluzole use (HR 0.72 95% CI 0.61-0.85) and attendance at an ALS clinic (HR 0.74 95% CI 0.64-0.86).<h4>Discussion</h4>Our analysis explored the strengths and weaknesses of Cox proportional hazard and Royston-Parmar flexible parametric methods. By including time varying components we were able to gain deeper understanding of the dataset. Variation in survival between time periods appears to be due to missing data in the first time period. The use of age as timescale to account for confounding by age resolved breaches of the proportional hazards assumption, but in doing so may have obscured deficiencies in the data. Our study demonstrates the need to test for, and fully explore, breaches of the Cox proportional hazards assumption. Royston-Parmar flexible parametric modeling proved a powerful method for achieving this.James RooneySusan ByrneMark HeverinBernie CorrMarwa ElaminAnthony StainesBen GoldacreOrla HardimanPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 8, Iss 9, p e74733 (2013)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
James Rooney
Susan Byrne
Mark Heverin
Bernie Corr
Marwa Elamin
Anthony Staines
Ben Goldacre
Orla Hardiman
Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
description <h4>Introduction</h4>The Irish ALS register is a valuable resource for examining survival factors in Irish ALS patients. Cox regression has become the default tool for survival analysis, but recently new classes of flexible parametric survival analysis tools known as Royston-Parmar models have become available.<h4>Methods</h4>We employed Cox proportional hazards and Royston-Parmar flexible parametric modeling to examine factors affecting survival in Irish ALS patients. We further examined the effect of choice of timescale on Cox models and the proportional hazards assumption, and extended both Cox and Royston-Parmar models with time varying components.<h4>Results</h4>On comparison of models we chose a Royston-Parmar proportional hazards model without time varying covariates as the best fit. Using this model we confirmed the association of known survival markers in ALS including age at diagnosis (Hazard Ratio (HR) 1.34 per 10 year increase; 95% CI 1.26-1.42), diagnostic delay (HR 0.96 per 12 weeks delay; 95% CI 0.94-0.97), Definite ALS (HR 1.47 95% CI 1.17-1.84), bulbar onset disease (HR 1.58 95% CI 1.33-1.87), riluzole use (HR 0.72 95% CI 0.61-0.85) and attendance at an ALS clinic (HR 0.74 95% CI 0.64-0.86).<h4>Discussion</h4>Our analysis explored the strengths and weaknesses of Cox proportional hazard and Royston-Parmar flexible parametric methods. By including time varying components we were able to gain deeper understanding of the dataset. Variation in survival between time periods appears to be due to missing data in the first time period. The use of age as timescale to account for confounding by age resolved breaches of the proportional hazards assumption, but in doing so may have obscured deficiencies in the data. Our study demonstrates the need to test for, and fully explore, breaches of the Cox proportional hazards assumption. Royston-Parmar flexible parametric modeling proved a powerful method for achieving this.
format article
author James Rooney
Susan Byrne
Mark Heverin
Bernie Corr
Marwa Elamin
Anthony Staines
Ben Goldacre
Orla Hardiman
author_facet James Rooney
Susan Byrne
Mark Heverin
Bernie Corr
Marwa Elamin
Anthony Staines
Ben Goldacre
Orla Hardiman
author_sort James Rooney
title Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
title_short Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
title_full Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
title_fullStr Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
title_full_unstemmed Survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
title_sort survival analysis of irish amyotrophic lateral sclerosis patients diagnosed from 1995-2010.
publisher Public Library of Science (PLoS)
publishDate 2013
url https://doaj.org/article/595c479a6df84ac795cde15011844858
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AT susanbyrne survivalanalysisofirishamyotrophiclateralsclerosispatientsdiagnosedfrom19952010
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AT berniecorr survivalanalysisofirishamyotrophiclateralsclerosispatientsdiagnosedfrom19952010
AT marwaelamin survivalanalysisofirishamyotrophiclateralsclerosispatientsdiagnosedfrom19952010
AT anthonystaines survivalanalysisofirishamyotrophiclateralsclerosispatientsdiagnosedfrom19952010
AT bengoldacre survivalanalysisofirishamyotrophiclateralsclerosispatientsdiagnosedfrom19952010
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