Long COVID (persistent COVID) represents a major global health challenge due to its high prevalence (approximately 7%), significant impact on quality of life, and socioeconomic burden. Despite extensive research, diagnostic tools to objectively identify or predict long COVID evolution are still lacking.
The BioICOPER Follow-up Study aims to analyze the influence of biomarker evolution on clinical symptomatology (particularly chronic fatigue) and vascular health after four years of follow-up among 400 participants previously included in the original BioICOPER cohort.
Advanced proteomic analysis, vascular function assessment, and machine-learning-based predictive modeling will be used to identify biomarkers associated with disease progression, stratified by sex. This project will contribute to personalized clinical management of long COVID and improved diagnostic and therapeutic strategies in primary care.
Adults ≥18 years old.
Confirmed previous SARS-CoV-2 infection.
Diagnosis of long COVID according to WHO criteria.
Participation in the baseline BioICOPER study.
Acute illness preventing participation.
Cognitive or physical impairment limiting data collection.
Withdrawal of informed consent.
Age < 18 years old
Adults previously enrolled in the BioICOPER study with a clinical diagnosis of long COVID.
Cohort
Prospective
BioICOPER Long COVID Cohort
Other interventionThis observational cohort includes 400 adult participants previously enrolled in the baseline BioICOPER study (2021-2023), who had a confirmed diagnosis of long COVID (persistent COVID-19) according to WHO criteria. Participants will undergo a comprehensive four-year follow-up assessment to evaluate clinical evolution, vascular function, and biological markers of disease persistence and recovery. There is no intervention assigned by the investigators - participants will continue their usual medical care. The study will observe natural disease progression and its association with biomarkers, vascular measurements, and lifestyle factors.
Progression of vascular stiffness measured by carotid-femoral pulse wave velocity (cfPWV)
Carotid-femoral pulse wave velocity will be assessed as the gold-standard measure of arterial stiffness, using the SphygmoCor® system. The study will evaluate the longitudinal change in cfPWV between baseline (BioICOPER inclusion) and the 4-year follow-up visit, in order to determine whether long COVID is associated with accelerated vascular aging.
Change in Fatigue Severity Score (FSS)
Fatigue assessed using a validated fatigue scale (Fatigue Severity Scale, FSS). The Fatigue Severity Scale (FSS) is a method of evaluating the impact of fatigue on you. The FSS is a short questionnaire that requires the patient to rate their level of fatigue. The FSS questionnaire contains nine statements that rate the severity of their fatigue symptoms. the patient needs to read each statement and circle a number from 1 to 7, based on how accurately it reflects their condition during the previous week and the extent to which they agree or disagree that the statement applies to them. A low value (e.g., 1) indicates strong disagreement with the statement, whereas a high value (e.g., 7) indicates strong agreement. The goal of this outcome is to determine how fatigue severity evolves and its association with biomarkers and vascular parameters.
Change in Health-Related Quality of Life (EQ-5D-5L or SF-36)
EQ-5D-5L is a health-related quality of life survey that uses five questions, each with five severity levels, to measure health status across the dimensions of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Health state profile: A person's answers create a five-number profile that describes their current health state. Scoring: This profile can be used to calculate a single index score that represents health-related quality of life. This score ranges from 0 (death) to 1 (full health). It assesses eight health concepts: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health. The SF-36 survey grades health by scoring responses on eight different health domains, which are then converted to a 0-100 scale where higher scores indicate better health. A score of 100 represents the best possible health in that category, while 0 represents the worst.
Change in Cognitive Function (Montreal Cognitive Assessment, MoCA)
Evaluate cognitive impairment associated with long COVID using the Montreal Cognitive Assessment, which is a 10-minute screening test used to detect mild cognitive impairment in adults. It is a 30-point test that evaluates several cognitive domains, including memory, attention, language, visuospatial skills, executive functions, and orientation. A score of 26 or above is considered a normal result, while lower scores may indicate some level of cognitive dysfunction. The goal of this assesment is to identify determinants of neurocognitive persistence or recovery.
Change in Physical Activity (WHO Physical Activity Questionnaire + 7-day pedometer readings)
Objectively and subjectively measure physical activity levels using both WHO Physical Activity Questionnaire and 7-day pedometer readings. The WHO Physical Activity Questionnaire is a 16 question instrument that assesses physical activity participation in three domains (activity at work, travel to and from places, and recreational activities) as well as sedentary behavior. Physical activity may include planned activity such as walking, running, basketball, or other sports. Physical activity may also include other daily activities such as household chores, yard work, walking the dog, etc. The use of the pedometer only completes the questionnaire, hence both variables need to be meassured simultaneously and interpret them together in order to determine changes in physical activity.
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Instituto de Investigación Biomédica de Salamanca
Lead sponsor
Carlos III Health Institute
Collaborator
