Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies

Introduction: Delayed Cerebral Ischemia (DCI) is an important cause of morbidity and mortality after aneurysmal Subarachnoid Hemorrhage (aSAH). Researchers have utilized various methods for predicting patients at risk for DCI progression. Methods: An eight-year retrospective review of aSAH patients...

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Main Authors: Georgios Alexopoulos, Justin Zhang, Ioannis Karampelas, Maheen Khan, Nabiha Quadri, Mayur Patel, Niel Patel, Mohammad Almajali, Tobias A. Mattei, Joanna Kemp, Jeroen Coppens, Philippe Mercier
Format: Article
Language:English
Published: Elsevier 2022-01-01
Series:Informatics in Medicine Unlocked
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Online Access:http://www.sciencedirect.com/science/article/pii/S2352914821002823
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author Georgios Alexopoulos
Justin Zhang
Ioannis Karampelas
Maheen Khan
Nabiha Quadri
Mayur Patel
Niel Patel
Mohammad Almajali
Tobias A. Mattei
Joanna Kemp
Jeroen Coppens
Philippe Mercier
author_facet Georgios Alexopoulos
Justin Zhang
Ioannis Karampelas
Maheen Khan
Nabiha Quadri
Mayur Patel
Niel Patel
Mohammad Almajali
Tobias A. Mattei
Joanna Kemp
Jeroen Coppens
Philippe Mercier
author_sort Georgios Alexopoulos
collection DOAJ
description Introduction: Delayed Cerebral Ischemia (DCI) is an important cause of morbidity and mortality after aneurysmal Subarachnoid Hemorrhage (aSAH). Researchers have utilized various methods for predicting patients at risk for DCI progression. Methods: An eight-year retrospective review of aSAH patients who presented to St Louis University Hospital. The records were screened for demographic, clinical, and radiographic parameters. DCI was the primary outcome. We identified 16 features to fit various forecasting models and selected the best binary classifier through comprehensive machine learning (ML) workflows. Regression and ensemble tree-based algorithms were utilized, based on their performance on tabular data. We investigated whether a single model could outperform in our dataset. Due to the expected outcome class imbalance (DCI), we selected precision, recall, and F-score as threshold metrics. Precision-recall curves were used for model performance ranking. Results: Of the 213 aSAH patients analyzed, 42 progressed to DCI (19.7%). The mean age was 55.7 years. The outcome variable (DCI) was imbalanced with a class ratio of 1:4. Bivariate analysis revealed two significant associations: The “Hunt-and-Hess scale” (p-value = 0.016), and “Posthemorrhagic hydrocephalus” (p-value < 0.001). The all-relevant important factors during feature selection were: “Fisher scale,” “Modified Fisher scale,” “Hunt-and-Hess scale,” and “Posthemorrhagic hydrocephalus”. “Treatment type” was tentative. The random forests model achieved a pooled accuracy of 71.1% (95%CI: 60.4, 83.4) with an F1-score of 0.484. The best binary classifier utilized extreme gradient boosting while trained on the all-relevant predictors plus “Aneurysm type.” Extreme gradient boosting achieved a predictive accuracy of 84.3% (95%CI: 75.9, 93.4) with an F1-score of 0.684. We describe the challenges that arise during training of a binary classifier on imbalanced datasets, and, while going through an extensive comparison review of similar published studies, we not only demonstrate the model's performance but also identify multiple forecasting methodological fallacies in neurological research. Conclusion: By implementing baseline patient characteristics combined with radiographic grading scales, we built a simple yet robust, highly accurate—but, most importantly—useful binary classifier for DCI prediction. The model is available online, and it can be utilized clinically as an effective forecasting tool (https://georgiosalexopoulos.shinyapps.io/download/).
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spelling doaj.art-d4f1039244c143a2b6281940cf6eec702022-12-22T04:06:12ZengElsevierInformatics in Medicine Unlocked2352-91482022-01-0128100817Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallaciesGeorgios Alexopoulos0Justin Zhang1Ioannis Karampelas2Maheen Khan3Nabiha Quadri4Mayur Patel5Niel Patel6Mohammad Almajali7Tobias A. Mattei8Joanna Kemp9Jeroen Coppens10Philippe Mercier11Department of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USA; Corresponding author. Department of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA.School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Banner Neurological Surgery Clinic, 1800 15th St Ste 100B Grand, Greeley, CO, 80631, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USASchool of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USASchool of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurology, Saint Louis University Hospital, 1438 S. Grand Blvd., St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USADepartment of Neurosurgery, Saint Louis University Hospital, 1201 S. Grand Blvd., St. Louis, Missouri, 63104, USA; School of Medicine, Saint Louis University, 1402 S. Grand Blvd, St. Louis, Missouri, 63104, USAIntroduction: Delayed Cerebral Ischemia (DCI) is an important cause of morbidity and mortality after aneurysmal Subarachnoid Hemorrhage (aSAH). Researchers have utilized various methods for predicting patients at risk for DCI progression. Methods: An eight-year retrospective review of aSAH patients who presented to St Louis University Hospital. The records were screened for demographic, clinical, and radiographic parameters. DCI was the primary outcome. We identified 16 features to fit various forecasting models and selected the best binary classifier through comprehensive machine learning (ML) workflows. Regression and ensemble tree-based algorithms were utilized, based on their performance on tabular data. We investigated whether a single model could outperform in our dataset. Due to the expected outcome class imbalance (DCI), we selected precision, recall, and F-score as threshold metrics. Precision-recall curves were used for model performance ranking. Results: Of the 213 aSAH patients analyzed, 42 progressed to DCI (19.7%). The mean age was 55.7 years. The outcome variable (DCI) was imbalanced with a class ratio of 1:4. Bivariate analysis revealed two significant associations: The “Hunt-and-Hess scale” (p-value = 0.016), and “Posthemorrhagic hydrocephalus” (p-value < 0.001). The all-relevant important factors during feature selection were: “Fisher scale,” “Modified Fisher scale,” “Hunt-and-Hess scale,” and “Posthemorrhagic hydrocephalus”. “Treatment type” was tentative. The random forests model achieved a pooled accuracy of 71.1% (95%CI: 60.4, 83.4) with an F1-score of 0.484. The best binary classifier utilized extreme gradient boosting while trained on the all-relevant predictors plus “Aneurysm type.” Extreme gradient boosting achieved a predictive accuracy of 84.3% (95%CI: 75.9, 93.4) with an F1-score of 0.684. We describe the challenges that arise during training of a binary classifier on imbalanced datasets, and, while going through an extensive comparison review of similar published studies, we not only demonstrate the model's performance but also identify multiple forecasting methodological fallacies in neurological research. Conclusion: By implementing baseline patient characteristics combined with radiographic grading scales, we built a simple yet robust, highly accurate—but, most importantly—useful binary classifier for DCI prediction. The model is available online, and it can be utilized clinically as an effective forecasting tool (https://georgiosalexopoulos.shinyapps.io/download/).http://www.sciencedirect.com/science/article/pii/S2352914821002823Delayed cerebral ischemiaClinical vasospasmSubarachnoid hemorrhageApplied predictive modelingApplied forecastingImbalanced binary classification
spellingShingle Georgios Alexopoulos
Justin Zhang
Ioannis Karampelas
Maheen Khan
Nabiha Quadri
Mayur Patel
Niel Patel
Mohammad Almajali
Tobias A. Mattei
Joanna Kemp
Jeroen Coppens
Philippe Mercier
Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
Informatics in Medicine Unlocked
Delayed cerebral ischemia
Clinical vasospasm
Subarachnoid hemorrhage
Applied predictive modeling
Applied forecasting
Imbalanced binary classification
title Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
title_full Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
title_fullStr Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
title_full_unstemmed Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
title_short Applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage: Methodological fallacies
title_sort applied forecasting for delayed cerebral ischemia prediction post subarachnoid hemorrhage methodological fallacies
topic Delayed cerebral ischemia
Clinical vasospasm
Subarachnoid hemorrhage
Applied predictive modeling
Applied forecasting
Imbalanced binary classification
url http://www.sciencedirect.com/science/article/pii/S2352914821002823
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