Clinical Diagnostic Workup
As previously described(20), a detailed medical history, blood tests,
physical examination, oxygen saturation and blood pressure were obtained
from all patients. Body mass indices (BMI; kg/m²) were assessed using
BMI-centiles adapted to age, sex, and race. All further consultations
with other medical specialists were conducted based on clinical
presentation. Electroencephalogram (EEG), electrocardiogram (ECG),
echocardiography, ultrasound of the abdomen and thyroid, chest-X-rays,
lung function with lung clearance index (LCI) measurement, cranial or
spinal magnetic resonance imaging, and Nerve Conduction Velocity (NCV)
were performed, if necessary, based on clinical presentation.
Demographic variables, preexisting diagnoses, and newly detected
underlying diseases as well as long COVID-associated symptoms were
documented. PASC associated symptoms were assessed through a
questionnaire (see supplementary file) and/or medical history. Shortness
of breath/exercise intolerance were associated via the six-minute
walking test. Patients were systematically queried as to symptoms
associated with long COVID or other somatic symptoms were included in
the evaluation. An improvement was defined by less reported intensity,
quantity of symptoms, and/or alleviation of restrictions in daily
routines, and numbers of symptoms or less restrictions in daily routines
caused by long COVID symptoms.