MEXICO: Mechanisms Underlying Long-term Fatigue and Exercise Intolerance Following CoV-2 Infection
Study Details
Study Description
Brief Summary
The MEXICO study is an observational study that aims to identify underlying mechanisms contributing to severe exercise intolerance in the presence of persistent COVID-19 symptoms (Long COVID).
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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Detailed Description
Persistent symptoms of fatigue and severe exercise intolerance have been observed in some patients following infection with CoV-2. Termed 'Long COVID', these symptoms may persist for months after the acute infection has resolved. The mechanisms underlying exercise intolerance in Long COVID are not fully understood and could be the result of dysfunction at any point along the transfer pathway of oxygen from atmosphere to skeletal muscle (uptake in the lungs, heart and blood vessel function and metabolism within skeletal muscle).
The MEXICO study aims to assess the function of key components of the oxygen transport pathway and compare results between 2 groups of patients with Long COVID; those who have severely impaired exercise capacity versus those with persistent fatigue but preserved exercise capacity. The study will assess 56 symptomatic patients who have been referred for further clinical investigation following CoV-2 infection. Participants will undertake assessment of lung function, exercise capacity, cardiac and vascular function and skeletal muscle strength and capacity for oxygen extraction at an initial study visit and then 9 months later at a follow-up visit.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Long COVID with severe exercise impairment Patients with prior serological or clinical diagnosis of CoV-2 infection and a referred to the UCLH Long-COVID clinic for persistent fatigue or exercise intolerance. An abnormal response on 6 minute walk test including any one of: Peripheral oxygen desaturation < 85% predicted walk distance Lactate rise> 1.0 from baseline Borg score > 5 for breathlessness or fatigue at end of test |
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| Long COVID with preserved exercise capacity Patients with prior serological or clinical diagnosis of CoV-2 infection and a referred to the UCLH Long-COVID clinic for persistent fatigue. |
Outcome Measures
Primary Outcome Measures
- Pulmonary function (spirometry) [Baseline]
Pulmonary function (ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) (FEV1/FVC)), measured using spirometry, is a co-primary outcome. Compare pulmonary function between long COVID patients with and without severe exercise impairment.
- Cardiac function (echocardiography) [Baseline]
Cardiac function (ejection fraction), measured by echocardiography, is a co-primary outcome. Characterise and compare cardiac function between long COVID patients with and without severe exercise impairment.
- Microvascular function (microvascular reactivity) [Baseline]
Microvascular reactivity, measured by near-infrared Spectroscopy (NIRS), is a co-primary outcome. Characterise and compare microvascular function between long COVID patients with and without severe exercise impairment.
- Macrovascular function (central BP) [Baseline]
Central blood pressure, measured by pulse wave analysis, is a co-primary outcome. Characterise and compare macrovascular function between long COVID patients with and without severe exercise impairment.
- Skeletal muscle oxidative capacity [Baseline]
Skeletal muscle oxidative capacity (assessed as the rate of oxygen consumption recovery post-exercise), measured using NIRS, is a co-primary outcome. Characterise and compare skeletal muscle oxidative capacity between long COVID patients with and without severe exercise impairment.
Secondary Outcome Measures
- Change in cardiorespiratory fitness (VO2max) [Baseline and 9 months]
Compare changes in VO2max, measured on cardiopulmonary exercise testing, to changes in key markers of the oxygen transport pathway (the primary outcomes).
Eligibility Criteria
Criteria
Inclusion Criteria:
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Serological or clinical diagnosis of CoV-2 infection
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Ability to provide written informed consent.
Inclusion criteria specifically for the impaired exercise capacity group includes an abnormal response on 6 minute walk test including any one of:
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Peripheral oxygen desaturation
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< 85% predicted walk distance
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Lactate rise> 1.0 from baseline
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Borg score > 5 for breathlessness or fatigue at end of test
Exclusion Criteria:
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< 18 years old.
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Considered a vulnerable adult
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Participant unwilling to consent
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Terminal illness or severe comorbidities affecting attendance or study investigations
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Pregnancy
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If the participant is not willing to give their consent for a clinical advisor to contact them if necessary
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Inability or presence of a contra-indication for exercise testing
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Chronic oral corticosteroid use (e.g. any maintenance dose of oral steroid, 4 or more course of oral steroid in previous 12 months, but not including prescription of dexamethasone during the acute episode of COVID-19, as long as that has been discontinued).
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | University College London | London | United Kingdom | WC1E6HX |
Sponsors and Collaborators
- University College, London
Investigators
- Principal Investigator: Professor Hughes, UCL, University College London
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 137711