One-year follow-up of COVID-19 recoverees with impaired pulmonary function: A prospective cohort study.

Decreased diffusion capacity for carbon monoxide (DLCO) is the most prevalent pulmonary testing abnormality among COVID-19 recoverees. We prospectively followed 51 individuals with impaired DLCO at an average of ∼3 months following COVID-19 and re-examined them at one year. At follow-up, mean DLCO increased from 68.0 % to 72.6 % (p = 0.002); while 33 % of the cohort experienced a clinically significant rise (>10 points) in DLCO, only 29 % normalized their values. While DLCO change did not correlate with symptoms, lack of improvement was more prevalent among individuals with obesity. Regardless of COVID-19 severity, a substantial proportion continued to exhibit DLCO impairment at 1-year.

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.