ABSTRACT
Background: Up to 80% of patients suffering from persistent symptoms more than six months after a COVID-19 infection complain about a variety of psychosomatic symptoms with no organ cause. Most patients suffer from chronic fatigue, pain, depression or difficulty concentrating. Experimental studies showed that these symptoms could be significantly improved after an open administration of placebos (“open-label placebo”) or with heart rate variability (HRV) biofeedback such as paced breathing. However, we insufficiently understand which patients benefit from which treatment. Methods: Patients (m/f) without organic causes for the complaints are randomised to three groups: an open-label placebo intervention (OLP), a paced breathing training (PBT) or no additional treatment (TAU). To detect a mean effect using a 2x3 ANOVA, N=90 patients will be included, and predictor analyses are performed. The OLP group takes 2 placebos/day and receives the information that placebos can significantly improve symptoms, e.g. via the activation of “self-healing powers”. The PBT group receives a standardized training to breath at 6 breaths/min for 10 min/day. At inclusion (T0) and after four (T1) and eight weeks (T2), treatment expectations, fatigue (FSMC), somatoform complaints, depressiveness, anxiety (PHQ), general health (SF-36) and quality of life, as well as cognitive performance using Corsi Span and Colour Stroop tests, will be assessed by questionnaires and tests, and an ECG will be recorded. Results: Preliminary results point to effective reductions of fatigue and other symptoms for both interventions compared to TAU, dependent on patients' individual factors such as treatment expectations, symptom severity during Covid-19 infection and at inclusion. HRV data will be analysed at the end of the study. Preliminary results will be presented at the conference. Conclusion: Patients with functional post-COVID syndromes can benefit from psychosomatic interventions aiming to improve treatment expectations and heart rate variability, depending on individual patients' factors. Patient-tailored interventions should be further investigated.