Chronic diseases span many months, even years intruding upon the lives of patients and their families. Many chronic diseases are uncertain in prognosis, phasing the disease, and response to treatment. Cure is problematic or impossible, so treatment concentrates in making the patient comfortable or relieving pain. Often patients suffer from multiple diseases or side effects of medical treatments lead to additional chronicity. Long-time use of drugs, routine monitoring and crisis requiring hospitalization make chronic diseases expensive. The extent to which patients succumb to the various effects of chronic disease are dependent upon numerous factors, in particular their psycho-social support, financial status, childhood experiences, sense of humour and determination to push on.
In 2001, chronic diseases such as cancer, asthma, Parkinson's, birth defects and diabetes were responsible for 7 out of 10 deaths in the USA. More than a third of the population, over 100 million men, women and children, suffered from one or more chronic illness, such as heart conditions, arthritis, rheumatism, autism, multiple sclerosis, leukaemia and impairments of back and spine. By 2020, studies estimate that chronic disease will afflict 134 million Americans and cost $1 million million a year. The Centers for Disease Control and Prevention estimates that 70% are preventable.