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.