Relationship between functional status and fatigue after COVID-19 infection: a multicenter study from Türkiye.

Background/aim: Symptoms of COVID-19 may persist for months. One of the persistent symptoms of COVID-19 is fatigue, which reduces functional status. The relationship between fatigue, functional status, and various other factors has received little attention, which this study aims to address.. Materials and methods: Patients with COVID-19 infection were included in this multicenter cross-sectional study. Age, sex, body mass index (BMI), marital status, smoking status, presence and duration of chronic disease, comorbidity index, regular exercise habits, time since COVID-19 diagnosis, hospitalization status, length of hospital stay, intubation status, home oxygen therapy after discharge, participation in a pulmonary rehabilitation program, presence of dyspnea, presence of cough, presence of sputum, and modified Medical Research Council, Post-COVID Functional Status (PCFS), Fatigue Severity Scale (FSS), and EQ-5D-5L Questionnaire scores were recorded. Results: We enrolled 1095 patients, including 603 (55%) men and 492 (45%) women with a mean age of 50 ± 14 years. The most common chronic lung disease was COPD (11%) and 266 (29%) patients had nonpulmonary disease. The median time elapsed since COVID-19 diagnosis was 5 months; the hospitalization rate was 47%. The median PCFS grade was 1 (0-4) and the median FSS score was 4.4 (1-7). The PCFS and FSS were positively correlated (r = 0.49, p < 0.01; OR: 1.88, 95% CI: 1.68-2.10). Both functional status and fatigue were associated with quality of life, which was lower in older patients, those with higher BMI, those with systemic disease, those not exercising regularly, and those with more severe COVID-19 infection (defined by dyspnea, pneumonia as indicated by computed tomography, hospitalization, length of stay, ICU admission, intubation, and the need for home oxygen after discharge). Conclusion: Fatigue may cause poorer functional status regardless of the time since COVID-19 diagnosis. In this study, patients with FSS scores of >4.78 showed moderate to severe functional limitations. It is important to address modifiable patient risk factors and reduce the severity of COVID-19 infection.

Interleukin-21: a potential biomarker for diagnosis and predicting prognosis in COVID-19 patients

Background/aim: COVID-19 patients have a wide spectrum of disease severity. Several biomarkers were evaluated as predictors for progression towards severe disease. IL-21 is a member of common γ-chain cytokine family and creates some specific effects during programming and maintenance of antiviral immunity. We aimed to assess IL-21 as a biomarker for diagnosis and outcome prediction in patients hospitalized with COVID-19. Materials and methods: Patients with a preliminary diagnosis of COVID-19 and pneumonia other than COVID-19 admitted to a tertiary care hospital were included consecutively in this comparative study. Results: The study population consisted of 51 patients with COVID-19 and 11 patients with non-COVID-19 pneumonia. Serum IL-21 concentration was markedly higher, and serum CRP concentration was significantly lower in COVID-19 patients compared to non-COVID-19 pneumonia patients. Within COVID-19 patients, 10 patients showed radiological and clinical progression. Patients with clinical worsening had lower lymphocyte count and haemoglobin. In addition to that, deteriorating patients had higher urea, LDH levels, and elevated concentration of both IL-6 and IL-21. The cut-off value of 106 ng/L for IL-21 has 80.0% sensitivity, %60.9 specificity for discriminating patients with clinical worsening. Multivariable analysis performed to define risk factors for disease progression identified IL-6 and IL-21 as independent predictors. Odds ratio for serum IL-6 concentrations ≥ 3.2 pg/mL was 8.07 (95% CI: 1.37-47.50, p = 0.04) and odds ratio for serum IL-21 concentrations ≥ 106 ng/L was 6.24 (95% CI: 1.04 ­ 37.3, p = 0.02). Conclusion: We identified specific differences in serum IL-21 between COVID-19 and non-COVID-19 pneumonia patients. Serum IL-21 measurement has promising predictive value for disease progression in COVID-19 patients. High serum IL-6 and IL-21 levels obtained upon admission are independent risk factors for clinical worsening.