A chronic condition is a human health condition or disease that is persistent or otherwise long-lasting in its effects or a disease that comes with time. The term chronic is often applied when the course of the disease lasts for more than three months. Common chronic diseases include arthritis, asthma, cancer, chronic obstructive pulmonary disease, diabetes, Lyme disease, and some viral diseases such as hepatitis C and acquired immunodeficiency syndrome. An illness which is lifelong because it ends in death is a terminal illness. It is possible and not unexpected for an illness to change in definition from terminal to chronic. Diabetes and HIV for example were once terminal yet are now considered chronic due to the availability of insulin and daily drug treatment for individuals with HIV which allow these individuals to live while managing symptoms.
In medicine, a chronic condition can be distinguished from one that is acute. An acute condition typically affects one portion of the body and responds to treatment. A chronic condition on the other hand usually affects multiple areas of the body, is not fully responsive to treatment, and persists for an extended period of time.
Chronic conditions may have periods of remission or relapse where the disease temporarily goes away, or subsequently reappears. Periods of remission and relapse are commonly discussed when referring to substance abuse disorders which some consider to fall under the category of chronic condition.
Chronic conditions are often associated with non-communicable diseases which are distinguished by their non-infectious causes. Some chronic conditions though, are caused by transmissible infections such as HIV/AIDS.
63% of all death's world wide are from chronic conditions. Chronic diseases constitute a major cause of mortality, and the World Health Organization (WHO) attributes 38 million deaths a year to non-communicable diseases. In the United States approximately 40% of adults have at least two chronic conditions.