Death from diabetic coma was the usual outcome of the disease before the discovery of insulin therapy. In both forms of diabetes, moderately elevated blood-sugar levels for many years can eventually cause kidney disease; impairment of sight due to rupture of blood vessels in the eyes; reduction of blood flow to the limbs, which can cause numbness and sometimes necessitates amputation; and alterations in nervous sensation. Diabetics also have an increased risk of heart attack and stroke. Uncontrolled diabetes in a pregnant woman is associated with increases in stillbirths and birth defects. The life span of an inadequately treated diabetic is shortened by about one-third.
Detection of Type II diabetes in the absence of symptoms starts with measurement of the glucose level in urine. If a high level is detected, the amount of blood sugar is measured after an overnight fast. A high value indicates diabetes, and those with a normal level then undergo an oral glucose tolerance test in which the amount of glucose in the blood is measured after ingestion of a large amount of the sugar.

Treatment
With adequate treatment most diabetics maintain blood-sugar levels within a normal or nearly normal range. This enables them to live normal lives and prevents some long-term consequences of the disease. For the Type I or Type II diabetic with little or no insulin production, therapy involves insulin injections and changes in diet. The diet requires distributing meals and snacks throughout the day so that the insulin supply is not overwhelmed and eating food that contains polysaccharides rather than simple sugars. (Polysaccharides must first be broken down in the stomach, therefore producing a much slower rise in blood sugar.) For Type II diabetics, most of whom are at least moderately overweight, the basics of therapy are diet control, weight reduction, and exercise. Weight reduction appears to partially reverse the condition of insulin resistance in the tissues. If a patient's blood-sugar level is still high, the physician may add insulin injections. An oral sugar-lowering agent may be prescribed for persons who do not require insulin addition to control their diabetes, as well as for those who have trouble injecting themselves or whose diabetes is not controlled by insulin addition.
Some diabetes patients are now equipped with insulin pumps, carried on the body, that deliver insulin at preset times and rates.