Criteria For Diagnosis Of Diabetes Mellitus

1. Symptoms of diabetes plus casual glucose concentration >200 mg/dL

(11.1 mmol/L). Casual is defined as any time of day without regard to time since last meal. The classic symptoms of diabetes include polyuria, polydispsia, and unexplained weight loss.

2. FPG >126 mg/dL (7.0 mmol/L). Fasting is defined as no caloric intake for at least 8 hours.

3. 2hPG >200 mg/dL during an OGTT. The test should be performed as described by WHO, using a glucose load containing the equivalent of 75-g anhydrous glucose dissolved in water.

FPG = fasting plasma glucose; OGTT = oral glucose tolerance test: 2hPG = 2-hour plasma glucose. From Powers AC. Diabetes mellitus. In: Braunwald E. Fauci AS. Kasper KL. et al. eds. Harrison's principles of internal medicine. 16th ed. New York: McGraw-Hill. 2005:2153.

macrovascular complications is seen at a fasting glucose >110 mg/dL. Once diabetes is diagnosed, therapy is instituted with three major goals.

1. Prevention of acute complications of hyperglycemia (e.g.. diabetic ketoacidosis or nonketotic hyperosmolar hyperglycemia) or hypoglycemia

2. Prevention of long-term complications of hyperglycemia, for example, microvascular disease such as retinopathy or nephropathy

3. Prevention of long-term complications of macrovascular disease, for example, cardiovascular or cerebrovascular disease

The foundation of diabetes therapy is dietary and lifestyle modifications. Randomized trials show that even small amounts of weight loss can lower blood pressure and improve glucose control. Patients should be given instruction in nutrition and encouraged to change sedentary lifestyles. Exercise that the patient finds enjoyable and possible should be encouraged. However, most people with diabetes will eventually require medications, and most patients will eventually require a combination of at least two medications. The United Kingdom Prospective Diabetes Study (UKPDS) followed almost 5000 patients over 20 years and compared intensive blood glucose control to conventional therapy in the prevention of macrovascular (coronary artery disease) and microvascular (retinopathy, nephropathy, and neuropathy) complications. Intensive therapy, with an HbAlc <7%, resulted in fewer microvascular complications, but there was no significant differences in macrovascular complications between the two groups. Patients in the intensive therapy group had more episodes of hypoglycemia, so intensive therapy may not be appropriate for elderly patients or those patients with other comorbid conditions.

The UKPDS randomized patients to begin treatment with either sulfonylureas or insulin therapy. A subgroup of overweight patients was started on metformin. In the end. those on insulin tended to gain more weight each year: otherwise, there were no differences between the groups. This has been interpreted to mean that any of these medications is an appropriate first choice in newly diagnosed diabetic patients. However, obese persons may benefit from metformin, as it has some effects on appetite and is associated with modest weight loss. Sulfonylureas are very inexpensive and effective. Other medications developed since the UKPDS may be added if needed (Table 42-3). If possible, introduction of insulin may be delayed because it leads to weight gain, which may worsen insulin resistance.

When diabetes is diagnosed, other cardiovascular risk factors should be assessed. Blood pressure and lipid levels should be measured. With regard to lipid therapy, the cardiovascular risk in those with diabetes is equivalent to those with known coronary artery disease, so the desired LDL threshold is <100 mg/dL. Those with higher LDL levels should undergo dietary modification or be started on a statin.

Table 42-3

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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