a long-term disease that cannot be completely cured and persists for a long time (usually more than three months, and often for life). Such diseases require constant medical monitoring and treatment, can occur with periods of exacerbation and remission, and also contribute to a decrease in the quality of life and disruption of daily human activity. Chronic diseases can occur for a variety of reasons, rarely disappear completely, and usually require a systematic approach to therapy and prevention of complications.