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Diabetes is a disease in which the body does not produce enough insulin or does not use insulin properly. Insulin is a hormone that allows glucose (sugar) to enter body cells where it is used as energy. With little or no insulin, glucose remains in the bloodstream instead of being used as fuel. High blood sugar levels are associated with diabetes. Treatment is aimed at keeping blood glucose near normal levels at all times, often by means of multiple insulin injections daily. Normal blood glucose levels are between 4.0 and 7.0 mmol/L when fasting, and between 5.0 and 10.0 mmol/L two hours after eating.1 Fasting levels between 6.1 and 6.9, however, may be evidence of pre-diabetes. If diabetes is improperly managed or left untreated, the high levels of blood sugar can increase the risk for serious complications.
Diabetes is the 6th leading cause of mortality in the world among adults aged 60 years and over.2 In 1999-2000, about 5.1% of the Canadian population aged 20 and over, or 1.2 million Canadians, were living with diabetes diagnosed by a health professional.3 Prevalence increases with age, peaking at 15.5% in the 75-79 year age group, and is generally higher among men than women.3 Age-standardized rates among Aboriginal peoples are triple the rates in the general population.4
However, studies suggest that there is a hidden burden from cases that go undiagnosed, which is estimated to be about one third of all diabetes cases. Using an adjustment factor* to account for undiagnosed cases, the estimated prevalence of diagnosed and undiagnosed cases could be as high as 1.8 million.
Diabetes results in both premature death and a reduction of functional health. This is due, in part, to the variety of complications that are associated with persistently high blood glucose levels over long periods of time. Health-adjusted life expectancy (HALE), a measure that combines the effects of morbidity and mortality associated with disease by adjusting for the years lived in less than full health, is reduced for both men and women living with diabetes. The HALE for men in Ontario is 58.3 years compared to 70 years for those without diabetes, while for women the HALE is 63.8 years for those with diabetes compared to 73.5 years for those without the disease.6
Many aspects of quality of life are affected by diabetes and its associated treatments. For instance, mild limitations are seen across many attributes of functional health, such as pain and discomfort (often due to needles required for injections), anxiety and fatigue. More severe impacts on functioning are not usually experienced until sequelae develop.
Complications of diabetes are caused by persistently high blood glucose levels, blood pressure and cholesterol; months and years of elevated levels can damage the blood vessels and nerves, increasing the risk for heart disease, blindness, nerve and kidney damage, and skin complications (e.g., bacterial and fungal infections, diabetic dermopathy).
This document presents the two main types of diabetes, type 1 and type 2. Type 1 diabetes is an autoimmune disorder that results in the body’s failure to produce insulin and is generally diagnosed in children and young adults. Type 2 diabetes can result from insulin resistance, or from the loss of the body’s ability to produce sufficient insulin. Type 2 diabetes is more common in the older population.
Gestational diabetes, experienced by pregnant women who did not have diabetes prior to pregnancy, is also presented here. Gestational diabetes is a temporary condition that is usually remedied once the pregnancy is over. It affects two to four percent of all pregnancies7-10 and greatly increases the risk of developing diabetes later in life. In the International Classification of Diseases,11 gestational diabetes is considered a complication related to pregnancy, and is coded under “Other conditions of the mother that complicate pregnancy”(648), “Gestational diabetes” (648.8).
This document also presents the most common sequelae of both type 1 and type 2 diabetes, including diabetic retinopathy, diabetic neuropathy, and diabetic foot. Two of these fall under other ICD-9 chapters: diabetic retinopathy falls under the classification of diabetes with ophthalmic manifestations (ICD-9 250.5) and is further classified within diseases of the nervous system and sense organs under diabetic retinopathy (362.0). Diabetic neuropathy is first classified under ICD-9 250.6, diabetes with neurological manifestations and then under musculoskeletal diseases as arthropathy associated with neurological disorders (713.5).
Complications that are sequelae of both diabetes and other diseases are presented in other documents in this series. These complications include blindness (Nervous System and Sense Organ Diseases), amputation (Injuries), ischemic heart diseases and stroke (Cardiovascular Diseases), chronic renal failure and end-stage renal disease (Genitourinary Diseases).
* An inflation rate is calculated based on an adjustment factor of 1/(1-0.33) — the 0.33 being the estimated percentage of undiagnosed cases5 — which equals 1.49. The adjustment factor multiplied by the number of diagnosed cases provides an estimate of total cases (diagnosed and undiagnosed).