Introduction:
Since the beginning of SARS-CoV-2-pandemic, intensive efforts have been made to identify predictors of COVID-19 outcomes. Individual components of the C2HEST-scale, used to predict the risk of atrial fibrillation, reflect comorbidities presences. Therefore, we hypothesized that the score could predict unfavorable clinical COVID-19-outcomes.

Material and methods:
2184-medical-records of subjects hospitalized at the medical-university-center due to COVID-19 from February 2020 to June 2021 were retrospectively analyzed . The subjects were categorized into low/medium/high-risk categories according to the C2HEST scale. Measured outcomes included: in-hospital-, 3-month- and 6-month-all-cause-mortality, the non-fatal hospitalization endpoints and other adverse in-hospital events.

Results:
A total of 598 deaths (27.4%), including 326 in-hospital (15%) were reported. All three types of mortality were highest in the high-risk C2HEST-stratum (35.4%, 54.4, and 56.9%), ,and lowest in the low-risk-stratum: (8.4%, 15%, and 37.5%), respectively. The receiver-operating characteristics revealed that C2HEST allows one to predict 1-month mortality with AUC30=70.7 and maintained at a similar level after 3- and 6-month-observation(AUC90=72.0 and AUC180=67). The p-value for the Log-rank test comparing survival curves was <0.0001. An increase of one C2HEST-point raised the overall death rate 1.4-fold. A change from the low- to medium category increased the death rate 3.4 times, while between the low- and high-risk-stratum the hazard-ratio was 5.0. The C2HEST-score also revealed predictive value for pneumonia, sepsis, cardiogenic-shock, myocardi-injury, acute heart failure, kidney/liver-injury, stroke, gastrointestinal-bleedings.

Conclusions:
The C2HEST-score is usefull in predicting adverse COVID-19-outcomes in hospitalized subjects. The simplicity of this scale, based on the presence of comorbidities, may address medical needs in risk stratification of COVID-19- patients.