Assessment of Exercise Capacity of Individuals with Long COVID: A Cross-sectional Study.

BACKGROUND: Clinical investigations of long-term effects of coronavirus disease 2019 (COVID-19) are rarely translated to objective findings. OBJECTIVES: To assess the functional capacity of individuals reported on deconditioning that hampered their return to their pre-COVID routine. METHODS: Assessment included the 6-minute walk test (6MWT) and the 30-second sit-to-stand test (30-STST). We compared the expected and observed scores using the Wilcoxon signed-rank test. Predictors of test scores were identified using linear regression models. RESULTS: We included 49 individuals, of whom 38 (77.6%) were recovering from mild COVID-19. Twenty-seven (55.1%) individuals had a 6MWT score lower than 80% of expected. The average 6MWT scores were 129.5 ± 121.2 meters and 12.2 ± 5.0 repeats lower than expected scores, respectively (P < 0.001 for both). The 6MWT score was 107.3 meters lower for individuals with severe COVID-19 (P = 0.013) and rose by 2.7 meters per each 1% increase in the diffusing capacity of carbon monoxide (P = 0.007). The 30-STST score was 3.0 repeats lower for individuals who reported moderate to severe myalgia (P = 0.038). CONCLUSIONS: Individuals with long COVID who report on deconditioning exhibit significantly decreased physical capacity, even following mild acute illness. Risk factors include severe COVID-19 and impaired diffusing capacity or myalgia during recovery.

Risk Factors and Multidimensional Assessment of Long Coronavirus Disease Fatigue: A Nested Case-Control Study.

BACKGROUND: Fatigue is the most prevalent and debilitating long-COVID (coronavirus disease) symptom; however, risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long-COVID fatigue and explored its possible pathophysiology. METHODS: This was a nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long-COVID fatigue. RESULTS: A total of 141 individuals were included. The mean age was 47 (SD: 13) years; 115 (82%) were recovering from mild coronavirus disease 2019 (COVID-19). Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long-COVID fatigue. They had a significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness, higher proportions of long-COVID symptoms, and of physical limitation in daily activities. Individuals with long-COVID fatigue also had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53); P = .038] and oxygen consumption per kilogram [27.69 (7.52) vs 30.71 (7.52); P = .036] at peak exercise. The 2 independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (OR: .79 per 10 beats/minute; 95% CI: .65-.96; P = .019) and long-COVID memory impairment (OR: 3.76; 95% CI: 1.57-9.01; P = .003). CONCLUSIONS: Long-COVID fatigue may be related to autonomic dysfunction, impaired cognition, and decreased mood. This may suggest a limbic-vagal pathophysiology. CLINICAL TRIALS REGISTRATION: NCT04851561.

Characteristics of long COVID among older adults: a cross-sectional study.

OBJECTIVE: To describe long-COVID symptoms among older adults, and to assess risk factors for two common long-COVID symptoms: fatigue and dyspnea. METHODS: Multicenter prospective cohort study, conducted in Israel, Switzerland, Spain, and Italy. Included were individuals at least 30 days since COVID-19 diagnosis. We compared long-COVID symptoms between elderly individuals (age>65 years) and younger population (18-65 years); and conducted univariate and multivariable analyses for predictors of long-COVID fatigue and dyspnea. RESULTS: 2333 individuals were evaluated at an average of 5 months [146 days (95% CI 142-150)] following COVID-19 onset. Mean age was 51 and 20.5% were>65 years. Older adults were more likely to be symptomatic, with most common symptoms being fatigue (38%) and dyspnea (30%). They were more likely to complain of cough and arthralgia, and have abnormal chest imaging and pulmonary function tests. Independent risk factors for long-COVID fatigue and dyspnea included female gender, obesity, and closer proximity to COVID-19 diagnosis; older age was not an independent predictor. CONCLUSIONS: Older individuals with long-COVID, have different persisting symptoms, with more pronounced pulmonary impairment. Women and individuals with obesity are at risk. Further research is warranted to investigate the natural history of long-COVID among the elderly population and to assess possible interventions aimed at promoting rehabilitation and well-being.

Patterns of Long COVID Symptoms: A Multi-Center Cross Sectional Study.

BACKGROUND: Long COVID has become a burden on healthcare systems worldwide. Research into the etiology and risk factors has been impeded by observing all diverse manifestations as part of a single entity. We aimed to determine patterns of symptoms in convalescing COVID-19 patients. METHODS: Symptomatic patients were recruited from four countries. Data were collected regarding demographics, comorbidities, acute disease and persistent symptoms. Factor analysis was performed to elucidate symptom patterns. Associations of the patterns with patients' characteristics, features of acute disease and effect on daily life were sought. RESULTS: We included 1027 symptomatic post-COVID individuals in the analysis. The majority of participants were graded as having a non-severe acute COVID-19 (N = 763, 74.3%). We identified six patterns of symptoms: cognitive, pain-syndrome, pulmonary, cardiac, anosmia-dysgeusia and headache. The cognitive pattern was the major symptoms pattern, explaining 26.2% of the variance; the other patterns each explained 6.5-9.5% of the variance. The cognitive pattern was higher in patients who were outpatients during the acute disease. The pain-syndrome pattern was associated with acute disease severity, higher in women and increased with age. The pulmonary pattern was associated with prior lung disease and severe acute disease. Only two of the patterns (cognitive and cardiac) were associated with failure to return to pre-COVID occupational and physical activity status. CONCLUSION: Long COVID diverse symptoms can be grouped into six unique patterns. Using these patterns in future research may improve our understanding of pathophysiology and risk factors of persistent COVID, provide homogenous terminology for clinical research, and direct therapeutic interventions.