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Comparability of Control and Comparison Groups in Studies Assessing Long COVID

BACKGROUND: Awareness of long coronavirus disease (COVID) began primarily through media and social media sources, which eventually led to the development of various definitions based on methodologies of varying quality. We sought to characterize comparison groups in long COVID studies and evaluate c...

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Autores principales: Haslam, Alyson, Prasad, Vinay
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier Inc. 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9912142/
https://www.ncbi.nlm.nih.gov/pubmed/36708796
http://dx.doi.org/10.1016/j.amjmed.2023.01.005
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author Haslam, Alyson
Prasad, Vinay
author_facet Haslam, Alyson
Prasad, Vinay
author_sort Haslam, Alyson
collection PubMed
description BACKGROUND: Awareness of long coronavirus disease (COVID) began primarily through media and social media sources, which eventually led to the development of various definitions based on methodologies of varying quality. We sought to characterize comparison groups in long COVID studies and evaluate comparability of the different groups. METHODS: We searched Embase, Web of Science, and PubMed for original research articles published in high-impact journals. We included studies on human patients with long COVID outcomes, and we abstracted study-related characteristics, as well as long COVID characteristics. RESULTS: Of the 83 studies, 3 were randomized controlled trials testing interventions for long COVID, and 80 (96.4%) were observational studies. Among the 80 observational studies, 76 (95%) were trying to understand the incidence, prevalence, and risk factors for long COVID, 2 (2.5%) examined prevention strategies, and 2 (2.5%) examined treatment strategies. Among those 80 studies, 45 (56.2%) utilized a control or comparison group and 35 (43.8%) did not. Compared with 95% of observational studies that documented symptoms or assessed risk factors, all randomized studies assessed treatment strategies. We found 48.8% of observational studies did any adjustment for covariates, including demographics or health status. Of those that did adjust for covariates, 15 (38.5%) adjusted for 4 or fewer variables. We found that 26.5% of all studies and 45.8% of studies with a control/comparator group matched participants on at least 1 variable. CONCLUSION: Long COVID studies in high-impact journals primarily examine symptoms and risk factors of long COVID; often lack an adequate comparison group and often do not control for potential confounders. Our results suggest that standardized definitions for long COVID, which are often based on data from uncontrolled and potentially biased studies, should be reviewed to ensure that they are based on objective data.
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spelling pubmed-99121422023-02-10 Comparability of Control and Comparison Groups in Studies Assessing Long COVID Haslam, Alyson Prasad, Vinay Am J Med Clinical Research Study BACKGROUND: Awareness of long coronavirus disease (COVID) began primarily through media and social media sources, which eventually led to the development of various definitions based on methodologies of varying quality. We sought to characterize comparison groups in long COVID studies and evaluate comparability of the different groups. METHODS: We searched Embase, Web of Science, and PubMed for original research articles published in high-impact journals. We included studies on human patients with long COVID outcomes, and we abstracted study-related characteristics, as well as long COVID characteristics. RESULTS: Of the 83 studies, 3 were randomized controlled trials testing interventions for long COVID, and 80 (96.4%) were observational studies. Among the 80 observational studies, 76 (95%) were trying to understand the incidence, prevalence, and risk factors for long COVID, 2 (2.5%) examined prevention strategies, and 2 (2.5%) examined treatment strategies. Among those 80 studies, 45 (56.2%) utilized a control or comparison group and 35 (43.8%) did not. Compared with 95% of observational studies that documented symptoms or assessed risk factors, all randomized studies assessed treatment strategies. We found 48.8% of observational studies did any adjustment for covariates, including demographics or health status. Of those that did adjust for covariates, 15 (38.5%) adjusted for 4 or fewer variables. We found that 26.5% of all studies and 45.8% of studies with a control/comparator group matched participants on at least 1 variable. CONCLUSION: Long COVID studies in high-impact journals primarily examine symptoms and risk factors of long COVID; often lack an adequate comparison group and often do not control for potential confounders. Our results suggest that standardized definitions for long COVID, which are often based on data from uncontrolled and potentially biased studies, should be reviewed to ensure that they are based on objective data. Elsevier Inc. 2023-01-25 /pmc/articles/PMC9912142/ /pubmed/36708796 http://dx.doi.org/10.1016/j.amjmed.2023.01.005 Text en © 2023 Elsevier Inc. All rights reserved. Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.
spellingShingle Clinical Research Study
Haslam, Alyson
Prasad, Vinay
Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title_full Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title_fullStr Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title_full_unstemmed Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title_short Comparability of Control and Comparison Groups in Studies Assessing Long COVID
title_sort comparability of control and comparison groups in studies assessing long covid
topic Clinical Research Study
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9912142/
https://www.ncbi.nlm.nih.gov/pubmed/36708796
http://dx.doi.org/10.1016/j.amjmed.2023.01.005
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