Evidence-based interconversion of the Glasgow Outcome and modified Rankin scales: pitfalls and best practices
Evidence-based interconversion of the Glasgow Outcome and modified Rankin scales: pitfalls and best practices
Objective: the aim of this study was to provide the evidence base to guide interconversion of the modified Rankin Scale (mRS) and Glasgow Outcome Scale (GOS) in neurological research.
Methods: a retrospective analysis of paired mRS and GOS recordings was conducted using datasets with the following selection criteria: (1) patients had haemorrhagic stroke, (2) simultaneous mRS and GOS measurements were available, and (3) data sharing was possible. The relationship between mRS and GOS was assessed using correlation analysis. The optimum dichotomisation thresholds for agreement between the mRS and GOS were identified using Cohen's kappa coefficient. Two-way conversion tables between mRS and GOS were developed based on the highest agreement between scores. Finally, to identify which direction of conversion (mRS to GOS or vice versa) was better, the Kolmogorov-Smirnov D statistic was calculated.
Results: using 3474 paired recordings the mRS and GOS were shown to be highly correlated (ρ = 0.90, p < 0.0001). The greatest agreement between the two scoring systems occurred when mRS=0-2 and GOS=4-5 was used to define good outcome (κ=0.83, 95% confidence interval: 0.81–0.85). Converting from mRS to GOS was better than the reverse direction as evidenced by a lower Kolmogorov-Smirnov statistic (D=0.054 compared to D=0.157).
Conclusions: this study demonstrates that the mRS and GOS are highly correlated, establishes the optimum dichotomisation threshold for agreement, provides a method for interconversion and shows that mRS to GOS conversion is superior to the reverse direction if a choice is available.
Glasgow outcome scale, Modified Rankin scale, Outcome, Stroke
Gaastra, Ben
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Ren, Dianxu
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Alexander, Sheila
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Awad, Issam A
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Blackburn, Spiros
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Doré, Sylvain
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Hanley, Dan
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Nyquist, Paul
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Bulters, Diederik
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Galea, Ian
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December 2022
Gaastra, Ben
c7b7f371-706b-4d59-9150-94e8f254e205
Ren, Dianxu
1b2b6a0a-4465-49a0-a23a-48c59d2d0a97
Alexander, Sheila
8a9ea84a-93d5-4b15-8182-b8e64ae38cc7
Awad, Issam A
cfd71c02-c2cd-45e5-9c65-c606ec3b0a63
Blackburn, Spiros
e2bfd052-b403-4c15-9422-626c260ddfd7
Doré, Sylvain
004e2fdb-3bf4-4143-b905-fd4e16f85cf5
Hanley, Dan
791268fa-e5cd-434b-8539-bceb03e08e73
Nyquist, Paul
e63d5518-c139-45fa-8694-74a202acd63e
Bulters, Diederik
d6f9644a-a32f-45d8-b5ed-be54486ec21d
Galea, Ian
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Gaastra, Ben, Ren, Dianxu, Alexander, Sheila, Awad, Issam A, Blackburn, Spiros, Doré, Sylvain, Hanley, Dan, Nyquist, Paul, Bulters, Diederik and Galea, Ian
(2022)
Evidence-based interconversion of the Glasgow Outcome and modified Rankin scales: pitfalls and best practices.
Journal of Stroke and Cerebrovascular Diseases, 31 (12), [106845].
(doi:10.1016/j.jstrokecerebrovasdis.2022.106845).
Abstract
Objective: the aim of this study was to provide the evidence base to guide interconversion of the modified Rankin Scale (mRS) and Glasgow Outcome Scale (GOS) in neurological research.
Methods: a retrospective analysis of paired mRS and GOS recordings was conducted using datasets with the following selection criteria: (1) patients had haemorrhagic stroke, (2) simultaneous mRS and GOS measurements were available, and (3) data sharing was possible. The relationship between mRS and GOS was assessed using correlation analysis. The optimum dichotomisation thresholds for agreement between the mRS and GOS were identified using Cohen's kappa coefficient. Two-way conversion tables between mRS and GOS were developed based on the highest agreement between scores. Finally, to identify which direction of conversion (mRS to GOS or vice versa) was better, the Kolmogorov-Smirnov D statistic was calculated.
Results: using 3474 paired recordings the mRS and GOS were shown to be highly correlated (ρ = 0.90, p < 0.0001). The greatest agreement between the two scoring systems occurred when mRS=0-2 and GOS=4-5 was used to define good outcome (κ=0.83, 95% confidence interval: 0.81–0.85). Converting from mRS to GOS was better than the reverse direction as evidenced by a lower Kolmogorov-Smirnov statistic (D=0.054 compared to D=0.157).
Conclusions: this study demonstrates that the mRS and GOS are highly correlated, establishes the optimum dichotomisation threshold for agreement, provides a method for interconversion and shows that mRS to GOS conversion is superior to the reverse direction if a choice is available.
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Accepted/In Press date: 11 October 2022
e-pub ahead of print date: 26 October 2022
Published date: December 2022
Additional Information:
Funding Information:
MISTIE III and CLEAR III were supported by grants from the NINDS (U01NS080824 and U01NS062851, respectively) and materials grants from Genentech. BG is funded by the Royal College of Surgeons, Society of British Neurological Surgeons, Barrow Foundation and the Guarantors of Brain.
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© 2022 The Authors
Keywords:
Glasgow outcome scale, Modified Rankin scale, Outcome, Stroke
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Local EPrints ID: 472065
URI: http://eprints.soton.ac.uk/id/eprint/472065
ISSN: 1052-3057
PURE UUID: b267e388-82ea-418e-a2ae-574eb36feafa
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Date deposited: 24 Nov 2022 18:36
Last modified: 17 Mar 2024 04:07
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Author:
Dianxu Ren
Author:
Sheila Alexander
Author:
Issam A Awad
Author:
Spiros Blackburn
Author:
Sylvain Doré
Author:
Dan Hanley
Author:
Paul Nyquist
Author:
Diederik Bulters
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