Life Expectancy in Untreated Type 2 Diabetes

Type 2 diabetes is a chronic condition that affects millions of people worldwide. Unlike type 1 diabetes, which is typically diagnosed in childhood and involves an absolute deficiency of insulin, type 2 diabetes is characterized by insulin resistance and relative insulin deficiency. The management of type 2 diabetes involves lifestyle modifications, oral medications, and sometimes insulin therapy. However, the focus of this article is on the potential life expectancy of individuals with untreated type 2 diabetes, highlighting the various factors that contribute to the progression of the disease and its complications.

Understanding Type 2 Diabetes

Type 2 diabetes primarily arises due to insulin resistance, where the body’s cells do not respond effectively to insulin, and beta-cell dysfunction, where the pancreas cannot produce enough insulin to overcome this resistance. Over time, high blood glucose levels can cause severe damage to various organs and systems in the body.

Pathophysiology and Progression

The pathophysiology of type 2 diabetes involves a complex interplay of genetic, environmental, and lifestyle factors. Individuals with a family history of diabetes, obesity, sedentary lifestyle, and poor dietary habits are at increased risk. The progression from prediabetes (a state of elevated blood sugar not yet in the diabetic range) to overt type 2 diabetes can span several years.

When type 2 diabetes is left untreated, hyperglycemia (high blood sugar levels) becomes chronic, leading to a host of complications:

• Macrovascular complications: These include cardiovascular diseases such as coronary artery disease, stroke, and peripheral artery disease. Hyperglycemia accelerates the process of atherosclerosis, leading to increased risk of heart attacks and strokes.
• Microvascular complications: Chronic high blood sugar levels damage small blood vessels, leading to conditions such as diabetic retinopathy (which can cause blindness), diabetic nephropathy (which can lead to kidney failure), and diabetic neuropathy (which can cause significant nerve damage and lead to amputations).

Impact on Life Expectancy

Untreated type 2 diabetes significantly reduces life expectancy. The degree of reduction in life expectancy depends on several factors, including the age at diagnosis, the presence of other comorbidities, and the severity and duration of hyperglycemia. Studies have shown that individuals with type 2 diabetes have a life expectancy that is approximately 10 years shorter than those without the condition, with untreated diabetes likely causing an even more significant reduction.

Complications and Their Consequences

Cardiovascular Diseases

Cardiovascular diseases are the leading cause of death among people with diabetes. The risk of heart disease and stroke is two to four times higher in individuals with diabetes compared to those without. High blood sugar levels contribute to the buildup of fatty deposits in the arteries, which can lead to heart attacks, heart failure, and other serious cardiovascular events.

Mechanisms:

• Atherosclerosis: Hyperglycemia promotes the formation of advanced glycation end products (AGEs) which contribute to vascular stiffness and atherosclerosis.
• Dyslipidemia: Diabetes often coexists with abnormal cholesterol levels, further increasing cardiovascular risk.
• Hypertension: High blood pressure is common in diabetes, compounding the risk of cardiovascular events.

Kidney Disease

Diabetic nephropathy is a leading cause of end-stage renal disease (ESRD). Persistent hyperglycemia causes damage to the glomeruli, the filtering units of the kidneys, leading to proteinuria (protein in the urine) and progressively worsening kidney function.

Impact:

• Chronic kidney disease (CKD): As kidney function declines, individuals may experience fatigue, swelling, and difficulty managing fluid balance.
• ESRD: At this stage, patients may require dialysis or a

kidney transplant to survive. Without treatment, the prognosis is poor, and ESRD significantly shortens life expectancy.

Eye Complications

Diabetic retinopathy is a leading cause of blindness in adults. High blood glucose levels damage the small blood vessels in the retina, leading to leakage, swelling, and eventually, vision loss. Untreated diabetes can also increase the risk of cataracts and glaucoma.

Stages of Retinopathy:

• Non-proliferative diabetic retinopathy (NPDR): Early stages where blood vessels in the retina weaken and leak fluid or blood, causing macular edema.
• Proliferative diabetic retinopathy (PDR): Advanced stage where new, abnormal blood vessels grow on the surface of the retina, which can bleed and cause severe vision loss.

Neuropathy

Diabetic neuropathy is nerve damage caused by chronic high blood sugar levels. It can affect various parts of the body, leading to significant morbidity.

Types:

• Peripheral neuropathy: Affects the feet and hands, causing pain, tingling, and loss of sensation. This increases the risk of injuries and infections, which can lead to amputations if not treated.
• Autonomic neuropathy: Affects the nerves that control internal organs, leading to gastrointestinal issues, bladder dysfunction, and cardiovascular problems such as orthostatic hypotension.

Foot Complications

Foot problems are common in untreated diabetes due to the combined effects of peripheral neuropathy and poor circulation. Minor injuries can lead to ulcers and infections, which can progress to gangrene and require amputation.