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Review
. 2023 Aug;53(8):e13989.
doi: 10.1111/eci.13989. Epub 2023 Apr 12.

The definition of long COVID used in interventional studies

Alyson Haslam  1 , Timothée Olivier  1   2 , Vinay Prasad  1
Affiliations
Free article
Review

The definition of long COVID used in interventional studies

Alyson Haslam et al. Eur J Clin Invest. 2023 Aug.
Free article

Abstract

Introduction: There has been little consensus for a specific definition of long COVID, though several organizations have created varying ones. We sought to examine the definition of long COVID used in ongoing clinical trials.

Methods: We searched 'long COVID' and related terms on both PubMed and clinicaltrials.gov for randomized studies that either included patients with long COVID or had a persistent or long-term COVID-related outcome and abstracted long COVID definition components.

Results: Of the 92 studies, a laboratory-only confirmed diagnosis of COVID-19 was stipulated in 54.3% (n = 50) studies. We found eight different time durations specified for how long symptoms needed to have occurred, ranging from 4 to 52 weeks, with 12 weeks being the most common (34.8%; n = 32). 35.9% (n = 33) did not specify a time duration. There were 57 different symptoms specified in total, with a median of one symptom identified per study (range 0-32). 8.7% of trials adhered to NICE or WHO definitions.

Conclusion: Standardized definitions of long COVID should be applied in studies assessing this condition to unify and harmonize research on this topic.

Keywords: COVID long-haulers; long COVID; persistent COVID; randomized studies.

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References

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