Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.

<h4>Objective</h4>To quantitate hypoxemia severity.<h4>Methods</h4>We developed the Weighted Hypoxemia Index to be adapted to different clinical settings by applying 5 steps to the oxygen saturation curve: (1) Identify desaturation/resaturation event [Formula: see text] by se...

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Main Authors: Diane C Lim, Cheng-Bang Chen, Ankita Paul, Yujie Wang, Jinyoung Kim, Soonhyun Yook, Emily Y Kim, Edison Q Kim, Anup Das, Medhi Wangpaichitr, Virend K Somers, Chi Hang Lee, Phyllis C Zee, Toshihiro Imamura, Hosung Kim
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0328214
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author Diane C Lim
Cheng-Bang Chen
Ankita Paul
Yujie Wang
Jinyoung Kim
Soonhyun Yook
Emily Y Kim
Edison Q Kim
Anup Das
Medhi Wangpaichitr
Virend K Somers
Chi Hang Lee
Phyllis C Zee
Toshihiro Imamura
Hosung Kim
author_facet Diane C Lim
Cheng-Bang Chen
Ankita Paul
Yujie Wang
Jinyoung Kim
Soonhyun Yook
Emily Y Kim
Edison Q Kim
Anup Das
Medhi Wangpaichitr
Virend K Somers
Chi Hang Lee
Phyllis C Zee
Toshihiro Imamura
Hosung Kim
author_sort Diane C Lim
collection DOAJ
description <h4>Objective</h4>To quantitate hypoxemia severity.<h4>Methods</h4>We developed the Weighted Hypoxemia Index to be adapted to different clinical settings by applying 5 steps to the oxygen saturation curve: (1) Identify desaturation/resaturation event [Formula: see text] by setting the upper threshold; (2) Exclude events as artifact by setting a lower threshold; (3) Calculate weighted area for each [Formula: see text] as [Formula: see text]; (4) Calculate a normalization factor [Formula: see text] for each subject; (5) Calculate the Weighted Hypoxemia Index as the summation of all weighted areas multiplied by [Formula: see text]. We assessed the Weighted Hypoxemia Index predictive value for all-cause mortality and cardiovascular mortality using the Sleep Heart Health Study (enrollment 1995-1998, 11.1 years mean follow-up).<h4>Results</h4>We set varying upper thresholds at 92%, 90%, 88%, and 86%, a lower threshold of 50%, calculated area under the curve and area above the curve, with and without a linear weighted factor (duration of each event [Formula: see text]), and used the same normalization factor of total sleep time <90% divided by total sleep time. After excluding subjects with missing data, we analyzed 4,509 participants (Alive: N = 3,769; All-cause mortality: N = 1,071; cardiovascular mortality: N = 330). Since the Weighted Hypoxemia Index-Area Under the Curve set at upper threshold of 90% (WHI-AUC90) had the best results in predicting all-cause mortality, we then compared it to the Apnea-Hypopnea Index and Total Sleep Time <90%. WHI-AUC90 showed statistical significance across quintiles for all-cause mortality, but not cardiovascular mortality, in adjusted Cox regression models.<h4>Conclusion</h4>The Weighted Hypoxemia Index offers a versatile and clinically relevant method for quantifying hypoxemia severity, with potential applications to evaluate mechanisms and outcomes across various patient populations.
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spelling doaj-art-0feb0c5e1a97494f8d18a5e952e69ba22025-08-20T03:13:30ZengPublic Library of Science (PLoS)PLoS ONE1932-62032025-01-01207e032821410.1371/journal.pone.0328214Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.Diane C LimCheng-Bang ChenAnkita PaulYujie WangJinyoung KimSoonhyun YookEmily Y KimEdison Q KimAnup DasMedhi WangpaichitrVirend K SomersChi Hang LeePhyllis C ZeeToshihiro ImamuraHosung Kim<h4>Objective</h4>To quantitate hypoxemia severity.<h4>Methods</h4>We developed the Weighted Hypoxemia Index to be adapted to different clinical settings by applying 5 steps to the oxygen saturation curve: (1) Identify desaturation/resaturation event [Formula: see text] by setting the upper threshold; (2) Exclude events as artifact by setting a lower threshold; (3) Calculate weighted area for each [Formula: see text] as [Formula: see text]; (4) Calculate a normalization factor [Formula: see text] for each subject; (5) Calculate the Weighted Hypoxemia Index as the summation of all weighted areas multiplied by [Formula: see text]. We assessed the Weighted Hypoxemia Index predictive value for all-cause mortality and cardiovascular mortality using the Sleep Heart Health Study (enrollment 1995-1998, 11.1 years mean follow-up).<h4>Results</h4>We set varying upper thresholds at 92%, 90%, 88%, and 86%, a lower threshold of 50%, calculated area under the curve and area above the curve, with and without a linear weighted factor (duration of each event [Formula: see text]), and used the same normalization factor of total sleep time <90% divided by total sleep time. After excluding subjects with missing data, we analyzed 4,509 participants (Alive: N = 3,769; All-cause mortality: N = 1,071; cardiovascular mortality: N = 330). Since the Weighted Hypoxemia Index-Area Under the Curve set at upper threshold of 90% (WHI-AUC90) had the best results in predicting all-cause mortality, we then compared it to the Apnea-Hypopnea Index and Total Sleep Time <90%. WHI-AUC90 showed statistical significance across quintiles for all-cause mortality, but not cardiovascular mortality, in adjusted Cox regression models.<h4>Conclusion</h4>The Weighted Hypoxemia Index offers a versatile and clinically relevant method for quantifying hypoxemia severity, with potential applications to evaluate mechanisms and outcomes across various patient populations.https://doi.org/10.1371/journal.pone.0328214
spellingShingle Diane C Lim
Cheng-Bang Chen
Ankita Paul
Yujie Wang
Jinyoung Kim
Soonhyun Yook
Emily Y Kim
Edison Q Kim
Anup Das
Medhi Wangpaichitr
Virend K Somers
Chi Hang Lee
Phyllis C Zee
Toshihiro Imamura
Hosung Kim
Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
PLoS ONE
title Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
title_full Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
title_fullStr Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
title_full_unstemmed Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
title_short Weighted Hypoxemia Index: An adaptable method for quantifying hypoxemia severity.
title_sort weighted hypoxemia index an adaptable method for quantifying hypoxemia severity
url https://doi.org/10.1371/journal.pone.0328214
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