Author(s): SICK, J., STEINBACHER, V., KOTNIK, D., KOENIG, F., RECKING, T., BENGSCH, D., KOENIG, D., Institution: UNIVERSITY OF VIENNA , Country: AUSTRIA, Abstract-ID: 603

INTRODUCTION:
Between 6.5 and 28.5% of people infected with SARS-CoV-2 experience long-lasting sequelae described as the Post-COVID-19 Syndrome (PCS). Recently, exercise has been investigated as a non-pharmacological therapy and it has shown to improve physical function, health-related quality of life and symptom severity. Nevertheless, some experts raised concerns about the implementation of exercise therapy in this population as post-exertional malaise (PEM) is a frequent symptom. This data analysis describes the characteristics of a study sample that discontinued an exercise intervention in order to identify possible predictors for dropout.
METHODS:
As part of a randomized controlled trial, 47 patients with PCS were allocated to 12 weeks of endurance or concurrent training. Patients with PEM or a Post-COVID-19 Functional Status Score of ≥3 were excluded. The sample was grouped into subjects that finished the intervention (n=28) and dropouts (n=19) and subsequently analyzed via a group comparison of metric (independent t-Test or U-Test) and categorical data (chi-squared test). Furthermore, a logistic regression model with several predictors (BMI, age, days since COVID-19 infection, VO2peak, SF36 score, fatigue score and number of symptoms) as well as the odds ratios for dropout of the most prevalent symptoms were calculated.
RESULTS:
Reasons for dropout were viral or bacterial infection (n=7), COVID-19 reinfection (n=5), compliance issues (n=4), worsening of symptoms (n=2) and injury (n=1). Dropouts and non-dropouts did not significantly differ in any demographic or outcome variable at baseline. A trend towards significance was found for the number of PCS symptoms reported at inclusion (non-dropouts: 4.7±2.6, dropouts: 6.4±3.2, p=0.058). No independent risk or protective factors were identified in the logistic regression (p=0.345). Dizziness was the only symptom significantly associated with dropout (OR: 7.6, 95% CI: 1.4; 42.1, p=0.021).
CONCLUSION:
Two subjects discontinued the training due to a worsening of their symptoms. Despite screening for exercise intolerance before enrollment, this could possibly be related to PEM. Otherwise, the overall high dropout-rate in this sample might be attributed to increased rates of respiratory tract infections and possible PCS-related alterations in immune function which increase susceptibility to infections. Dizziness could be a predictor for poor exercise tolerance, however further investigation and larger samples are needed.