Diabetes mellitus comprises 
several diseases of carbohydrate metabolism that are characterized by hyperglycemia caused by insulin secretion defects, decreased insulin sensitivity, or both. This chronic hyperglycemic state results in long-term dysfunction and failure of body organs including the eyes, kidneys, nerves, heart, and blood vessels.1


Two basic types of diabetes exist: type 1 and type 2. Type 1 diabetes involves beta-cell destruction that causes a defect in insulin secretion. In type 2 disease, patients have peripheral insulin resistance and a variable defect in insulin secretion. Ninety percent of type 2 dia­betic patients have a body mass index (BMI) greater than 23 kg/m2, and for each unit of increase in BMI, the risk for developing diabetes increases by 12%.2 In 2002, the per-capita cost of health care was $13,243 for people with diabetes versus $2,560 for those without diabetes.2 Currently, 171 million people worldwide have the disease, a figure expected to reach 366 million by 2030.3


DIAGNOSTIC CRITERIA


The criteria for diagnosing both types of diabetes, which are confirmed one at a time on subsequent days, include


  • Symptoms of diabetes (polyuria, polydypsia, and unexplained weight loss) plus a casual plasma glucose concentration 200 mg/dL or greater

  • Fasting plasma glucose (FPG) level 126 mg/dL or greater

  • A 2-hour oral glucose tolerance test (OGTT) of 200 mg/dL or greater

  • An A1C level of 6.5% or greater.


Prediabetes is often a precursor to type II diabetes. A fasting blood glucose level of 100 to 125 mg/dL or a 2-hour post-OGTT glucose level of 140 to 199 mg/dL defines prediabetes. At least 50% of people with impaired glucose tolerance develop type 2 diabetes.3


MORBIDITY / MORTALITY


Since type 2 diabetes is often asymptomatic, patients with newly diagnosed disease often have had diabetes for at least 4 to 7 years.3 Diabetes is the major cause of blindness in adults aged 20 to 74 years and causes 50% to 70% of all nontraumatic lower extremity amputations.3,4 Acute, life-threatening consequences of diabetes include hyperglycemia with ketoacidosis and nonketotic hyperosmolar syndrome. Macrovascular and microvascular damage cause retinopathy with potential loss of vision, nephropathy leading to renal failure, and peripheral neuropathy. Patients with diabetes have an increased risk of atherosclerotic cardiovascular and cerebrovascular disease, hypertension, and lipoprotein metabolism abnormalities.


TREATMENT GOALS


The goals of diabetes treatment are glycemic control and prevention of complications. To obtain glycemic control, changes in diet, exercise, and weight loss; patient education; and intensive pharmacologic therapy must be implemented. Every 1% drop in A1C yields improved outcomes.5


THE NEXT STEP


Patients should be regularly evaluated to screen for macrovascular and microvascular complications and diabetic retinopathy. Routine foot examinations should also be performed. An ophthalmologist should perform an initial dilated fundus examination on patients with type 1 diabetes within 5 years of the diagnosis and on patients with type II diabetes at the time of diagnosis. Subsequent examinations are performed annually.4 


Patients with diabetes have an increased risk of kidney disease and cor­onary heart disease.6 The Detection of Ischemia in Asymptomatic Diabetics study suggests that 1 in 5 asymptomatic patients with type 2 diabetes aged 50 to 75 years have silent myocardial ischemia.7 The ADA recommends screening diabetic patients with a cardiac stress test if they have a history of peripheral or carotid arterial disease and those older than 35 years with a sedentary lifestyle who are planning on starting a vigorous exercise program.8 JAAPA

Tina Butler and Lucille O'Brien are assistant professors and Tanya Favor and Rebecca Hamilton are PA students, all at the Texas Tech University Health Sciences Center PA program in Midland, Texas. The authors have indicated no relationships to disclose relating to the content of this article.


Mary L. Hewett, PA-C, MS, department editor


REFERENCES


1. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2010;33(suppl 1):S62-S69. http://care.diabetesjournals.org/content/33/Supplement_1/S62.full. Accessed February 8, 2011.


2. Niswender K. Diabetes and obesity: therapeutic targeting and risk reduction—a complex interplay. Diabetes Obes Metab. 2010;12(4):267-287.


3. Votey SR, Peters AL. eMedicine. Diabetes Mellitus, Type 2
—A Review. http://www.emedicine.medscape.com/article/766143-overview. Updated September 23, 2010. Accessed February 8, 2011.


4. Garg S, Davis RM. Diabetic Retinopathy Screening Update. Clin Diabetes. 2009;27(4):140-145.


5. McCulloch DK. UpToDate. Initial management of blood glucose in type 2 diabetes mellitus. http://www.uptodate.com/online/content/topic.do?topicKey=diabetes/19865&view=
print. Updated June 17, 2010. Accessed February 8, 2011.


6. Atkins RC, Zimmet P; 2010 International Society of Nephrology/
International Federation of Kidney Foundations World Kidney Day Steering Committee; International Diabetes 
Federation. Diabetic kidney disease: act now or pay later—World Kidney Day, 11 March 2010: we must act on diabetic kidney disease. Ther Apher Dial. 2010;14(1):1-4.


7. Bacus HB, Motala AA, Pirie FJ. Screening for asymptomatic coronary artery disease in type 2 diabetes mellitus. J Endocrinol Metabol Diabetes S Af. 2008;13(1):14-17.


8. McCulloch DK. UpToDate. Overview of medical care in adults with diabetes mellitus. http://www.uptodate.com/patients/content/topic.do?topicKey=~daanhQGLOLRXSAa. Updated June 16, 2010. Accessed February 8, 2011.


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