Dysautonomia may occur in long COVID-19 patients with fatigue

Patients with long novel coronavirus disease (COVID-19) with fatigue typically experience dysautonomia, which manifests as dysregulation of heart rate variability (HRV), as reflected by an altered nociception level (NOL) index, a recent study has found.

Thirty-nine patients participated in the present study: 12 with COVID-19 and fatigue, 15 with COVID-19 without fatigue, and 12 without either condition. All three groups were comparable in terms of age, sex, and comorbidities. HRV was reflected using the NOL index, which was derived from a pain monitoring system device.

Fatigue was defined as satisfying two of the following characteristics: scores in the Nijmegen Continuity Questionnaire ≥23, Post-traumatic Stress Disorder Checklist for DSM-5 (PCL-5) results >20, loss of body mass >10 percent, and 30 s of up and down test inferior to 3.

Patients with long COVID-19 with fatigue scored significantly higher on the Nijmegen Continuity Questionnaire (36 vs 20; p=0.002) and PCL-5 (31 vs 18; p=0.001) compared to those without fatigue. Loss of body mass >10 percent (p=0.632) and outcomes in the 30 s of up and down test (p=0.192) were comparable between groups.

Curves of NOL index revealed a significant dissociation over time between long COVID-19 patients with fatigue and control participants (p=0.046).

“Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, reflected by the NOL index, compared to control participants,” researchers said.

“Dysautonomia may explain the persistent symptoms observed in long COVID-19 participants, such as fatigue and hypoxia,” they added.