Y.I. Skvortsov - Dr. Sc. (Med.), Professor, Head of Department of Propaedeutics of Internal Diseases, GBOU VPO Saratov State Medical University named after V.I. Rasumovsky Healthcare Ministry of the Russian Federation V.V. Lisin - Ph. D. (Med.), Department of Propaedeutics of Internal Diseases, GBOU VPO Saratov State Medical University named after V.I. Rasumovsky Healthcare Ministry of the Russian Federation. E-mail: tat-lis-tat@yandex.ru