The student will be able to diagnose, classify, and manage diabetes mellitus in a clinic setting.
Type 1 Diabetes
Type 2 Diabetes
ranges from predominantly insulin resistant with relative insulin deficiency to predominantly an insulin secretory defect with insulin resistance. previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. autosomal dominant inheritance pattern is present. 80% to 90% of these patients are obese. 90% of diabetics in the United States are Type 2.
|STAGE||Fasting Plasma Glucose (FPG)(Preferred)*||
Casual Plasma Glucose
Oral Glucose Tolerance Test (OGTT)
|Diabetes||FPG 126 mg/dL (7.0 mmol/L)**||Casual plasma glucose 200 mg/dL (11.1 mmol/L) plus symptoms***||Two-hour plasma glucose (2hPG) 200 mg/dL****|
|Impaired Glucose Homeostasis||Impaired fasting glucose (IFG) = FPG 110 and < 126 g/dL||Impaired glucose tolerance (IGT) = 2hPG > 140 and < 200 mg/dL|
|Normal||FPG < 110 mg/dL||2hPG < 140 mg/dL|
* The FPG is the preferred test for diagnosis, but
any 1 of the 3 listed is acceptable. In the absence of unequivocal hyperglycemia
with acute metabolic decompensation, 1 of these 3 tests should be used
on a different day to confirm diagnosis.
** Fasting is defined as no caloric intake for at least 8 hours.
*** Casual = any time of day without regard to time since last meal; symptoms are the classic ones of polyuria, polydipsia, and unexplained weight loss.
**** OGTT should be performed using a glucose load containing the equivalent of 75 g anhydrous glucose dissolved in water. The OGTT is not recommended for routine clinical use.
From: Rayburn WE. Clinical perspectives: Diagnosis
and classification of diabetes mellitus: Highlights from the American Diabetes
Association. J Reprod Med 0024-7758/97/4209-0585.
|Table 2. Criteria for Testing in Asymptomatic Undiagnosed Individuals|
|Type 1 Diabetes: Testing presumably healthy individuals for
the presence of any immune markers, outside of a clinical trials setting,
is not recommended.
Type 2 Diabetes: In asymptomatic, undiagnosed individuals, testing for diabetes should be considered in all individuals at age 45 and above, and, if normal, it should be repeated at 3-year intervals.
Testing should be considered at a younger age, or be carried out more frequently, in individuals who:
Impaired Glucose Tolerance (IGT) and Impaired Fasting Glucose (IFG)
Patients with IGT respond abnormally to the glucose tolerance test, but do not meet the criteria required to diagnose diabetes. Patients with IFG have abnormal fasting glucose, but are not diagnostic for D.M. and have normal glucose tolerance tests. IGT and IFG are not clinical entities, but are risk factors for future D.M. and cardiovascular disease.
Diagnostic Criteria and Screening
HbA1c measurement is not currently recommended for diagnosis of D.M.
Goals of Therapy
Methods of Therapy
The cornerstone of therapy for all obese diabetics is a weight-reduction diet. This is especially true of the obese Type 2 diabetic. The primary emphasis is a reduction in total calories in order to effect a weight loss. This often requires a diet limiting daily intake to 1200 calories or less. Even a relatively small amount of weight loss usually achieves control (85% of patients), and continued, gradual weight loss will maintain control in the obese, Type 2 diabetic. Without weight loss in these patients, good control of the diabetes is very difficult to achieve.
The type of calories and timing of the meals is more important in the non-obese diabetic on insulin.
Increased fiber content may be of benefit.
A dietitian should be consulted for instruction and on-going supervision of the diabetic patient.
Adequate physical activity has been shown to increase insulin receptor
sites and lower insulin requirements. A regular exercise program should
|Table 3. Glycemic Control for People with Diabetes*|
|Biochemical Index||Nondiabetic||Goal||Additional Action Suggested|
|Preprandial glucose (mg/dL)**||< 110||80-120||< 80
|Bedtime glucose (mg/dL)**||< 120||100-140||< 100
|HbA1c (%)||< 6||< 7||> 8|
|* The values shown in this table are by
necessity generalized to the entire population of individuals with diabetes.
Patients with comorbid diseases, the very young and older adults, and others
with unusual conditions or circumstances may warrant different treatment
goals. These values are for nonpregnant adults. "Additional action suggested"
depends on individual patient circumstances. Such actions may include enhanced
diabetes self-management education, comanagement with a diabetes team,
referral to an endocrinologist, change in pharmacological therapy, initiation
of or increase in SMBG, or more frequent contact with the patient. HbA1c
is referenced to a nondiabetic range of 4.0-6.0% (mean 5.0%, SD 0.5%).
** Measurement of capillary blood glucose.
Oral Hypoglycemic Agents
Sulfonylureas may be used in Type 2 diabetics over 30 who have failed diet therapy, or as an adjunct while diet and exercise are being instituted. They are more likely to be effective in patients with mildly elevated glucose (FBS <300).
The second generation agents glyburide and glipizide are more potent and may be attempted in patients with marked hyperglycemia or who failed the first generation agents.
Sulfonylureas cannot be used during pregnancy and are contraindicated in patients with hepatic or renal dysfunction. Because of its long duration of action, glyburide should be avoided in elderly patients.
Metformin (Glucophage) is a new oral hypoglycemic agent that may be
used alone or in combination with a sulfonylurea agent. Combination therapy may delay or avoid insulin therapy when treatment with one oral agent has failed. Metformin is contraindicated in patients with renal dysfunction (serum creatinine 1.5 in men and 1.4 in women). Also avoid metformin in patients who have a history of binge drinking and those prone to dehydration.
Troglitazone (Rezulin) improves sensitivity to insulin in muscle and
adipose tissue and inhibits hepatic gluconeogenesis. It can be used as
monotherapy or in combination with other oral agents or insulin. It has
synergistic effects with sulfonylureas. When added to insulin, the dose
of insulin can usually be lowered approximately 50%. Disadvantages include
high cost and potential hepatic injury. Monitoring LFTs is required.
|Table 4. Sulfonylureas*|
|Drug||Tablet Size||Daily Dose||Duration of
|Tolbutamide (Orinase)||250 mg and500 mg||0.5-2 g in 2 or 3 divided doses||6-12 hours|
|Tolazamide(Tolinase)||100 mg, 250 mg, and 500 mg||0.1-l g as single dose or in 3 divided doses||Up to 24 hrs.|
|Glyburide (Diabeta, Micronase)||1.25 mg, 2.5 mg, and 5 mg doses||1.25-20 mg as single dose or in 2 divided||Up to 24 hrs.|
|Glipizide(Glucotrol)||5 mg and 10 mg||2.5-30 mg as single dose or in 2 or 3 divided doses on an empty stomach||6-12 hours|
|* All are available in generic.|
* This schedule assumes that the patient is receiving an optimum diabetic diet and that reliable plasma glucose data are available from hospital or home glucose monitoring.
Diabetes Mellitus. Theory and Practice, Third Edition, Eds. Ellenberg M, Rifkin H. Medical Examination Publishing Co., Inc., New York, 1983.
Be aware that secondary failures are common, and continued patient monitoring at regular intervals is necessary.
Insulin is required in Type 1 diabetics for even short-term survival. When obese Type 2 diabetics fail weight loss and oral hypoglycemic agents, insulin is necessary to control hyperglycemia.
Insulin may be started on an out-patient basis in the stable patient. Usually a single injection of inter mediate insulin (NPH or Lente) should be given prior to breakfast. Control may be obtained by increasing the intermediate insulin, addition of short-acting (regular) insulin, or giving a portion of the total daily insulin prior to the evening meal or, occasionally, at bedtime (see attached algorithm).
Split-dose therapy is usually necessary in Type 1 DM, and is often necessary in Type 2 patients who are difficult to control or who require large amounts of insulin (greater than 40 or 50 units).
Individual patient variations are frequent in the peak activity and duration of action of short-acting and intermediate-acting insulin, especially after longterm use of insulin. Intermediate-acting human insulin has an earlier onset and peak than beef/pork preparations.
Insulin is an appetite stimulant, especially in large doses, and makes weight reduction more difficult. This complicates therapy in the obese Type 2 diabetic, and many of these patients are on very high doses of insulin (> 100 units), with continued poor control. In the obese patient who becomes motivated to lose weight, reduction of insulin dosage is usually indicated, and this may allow further weight loss due to less appetite stimulation.
Insulin may be added to oral agents when secondary failure occurs. A simple approach is to give 10 units of NPH at bedtime and monitor FBS each morning. After 7 days, if FBS is >140, add 5 units. Continue to increase by 5 units each week until FBS is <140. When FBS is <120, reduce dose by 5 units.
Propanolol and other beta-blockers should be avoided if possible, in patients on insulin, since the warning symptoms of hypoglycemia will be masked, and dangerously low blood glucose levels can occur before the patient recognizes the problem.
Thiazide diuretics should be avoided because they increase insulin requirements and adversely affect glycemic control. Both thiazides and beta blockers adversely affect hyperlipidemia, a common coexisting disease in the diabetic. Many diabetic patients also have hypertension and are at high risk for nephropathy. The target BP in these patients is <130/85. ACE inhibitors have been shown to delay or prevent the nephropathy of DM and are therefore the treatment of choice when these conditions co-exist.
Methods of Monitoring Therapy
Team Approach. Members of the team include nurses for patient education and support groups, dietitions as mentioned above, physical therapists or podiatrists for on-going foot care, ophthalmologists for periodic exams to detect retinal changes at a treatable stage, and nephrologists when advanced renal impairment occurs.
Visits to ophthalmologists should occur annually. Retinal photography is indicated for any newly diagnosed diabetic, any Type 1 diabetic of 5 years or more, and all Type 2 diabetics.
A foot examination should be performed on each visit to detect early foot problems and to emphasize good foot care.
Urinalysis should be performed annually to detect proteinuria. Analysis for microalbuminuria can detect proteinuria at an earlier stage. Begin ACE inhibitor if proteinuria is detected.
American Diabetes Association. Standards of medical care for patients with diabetes mellitus. Diabetes Care, January 1998;21(Suppl 1):S23-S31.
Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care, January 1998;21(Suppl. 1):S5-S19.
American Diabetes Association: Clinical Practice Recommendations 2000; Volume 23 Supplement 1, January 2000
M. Harper, MD