Diabetes Mellitus - Clinical Presentation And Diagnosis
Clinical presentation and diagnosis
At least half of elderly individuals with diabetes are unaware that they have the disease, and often the diagnosis is made after the complications of the disease are established (Harris et al.). Although the reasons for late diagnosis of diabetes are unclear, it may be related to a lack of awareness of the diagnostic criteria on the part of physicians, lack of interaction by elderly patients with a physician, and the fact that elderly patients frequently do not manifest the classic symptoms of hyperglycemia: excessive secretion of urine, excessive thirst, and excessive appetite. Symptoms do not generally occur until blood glucose levels are substantially elevated, possibly because the level at which sugar spills into the urine increases with age. When patients do have symptoms, they are often nonspecific (e.g., failure to thrive, low energy, confusion, frequent urination, with or without incontinence, various infections), and may not always trigger the measurement of a plasma glucose level or a consultation with a physician. This phenomenon, along with the fact that identification and management of diabetes can relieve many of these symptoms, improve the quality of life, and prevent or delay subsequent chronic illnesses, highlights the importance of screening for diabetes in elderly individuals.
The diagnosis of diabetes may be accomplished by measuring fasting plasma glucose. It is currently recommended that fasting glucose be measured every three years in elderly persons and yearly in persons with risk factors for the development of diabetes, such as obesity, hypertension, and a strong family history of diabetes. The diagnosis of diabetes is made by a fasting plasma glucose of at least 7.0 millimol/liter on two occasions. A diagnosis can also be made when a patient is found to have a glucose of at least 11.1 millimol/liter two hours after a 75 gram oral glucose load (American Diabetes Association, 1997), but for practical reasons a glucose tolerance test is not generally performed.