Subdomains of Post-COVID Syndrome (PCS) - a population-based study.

Purpose: 'Post-COVID Syndrome' (PCS), which encompasses the multifaceted sequelae of COVID-19, can be severity-graded by a previously defined score encompassing 12 different long-term symptom complexes. The PCS score was shown to have two main predictors, namely acute COVID-19 severity and individual resilience. The purpose of the present study was to verify these predictors and to assess their detailed relationship to the symptom complexes constituting the PCS score.

Methods: The study drew upon a largely expanded dataset (n = 3,372) from COVIDOM, the cohort study underlying the original PCS score definition. Classification and Regression Tree (CART) analysis served to resolve the detailed relationship between the predictors and the constituting symptom complexes of the PCS score.

Results: Among newly recruited COVIDOM participants (n = 1,930), the PCS score was again found to be associated with both its putative predictors. Of the score-constituting symptom complexes, neurological symptoms, sleep disturbance, and fatigue were predicted by individual resilience whereas the acute disease severity predicted exercise intolerance, chemosensory deficits, joint or muscle pain, signs of infection, and fatigue. These associations inspired the definition of two novel PCS scores that included the above-mentioned subsets of symptom complexes only. Similar to the original PCS score, both novel scores were found to be inversely correlated with quality of life as measured by the EQ-5D-5L index.

Conclusion: The two newly defined PCS scores may enable a more refined assessment of PCS severity, both in a research context and to delineate distinct PCS subdomains with possibly different therapeutic and interventional needs in clinical practise.