Funding: the study was supported by the Russian Foundation for Basic Research under research project #20-313-90005.

Acknowledgments: the authors thank I.P. Zadoy, Chief Physician of the City Clinical Emergency Medical Station, for assistance in organizing the study.

Author contribution: Bolobonkina TA — data acquisition and analysis; Dementiev AA — study design development, data analysis; Minaeva NV — article authoring.

Compliance with ethical standards: the study was approved by the Ethics Committee of Ryazan State Medical University named after Academician I.P. Pavlov of the Ministry of Health of Russia (Minutes #2 of October 08, 2019); all participants signed an informed consent.