Treatment of Type 2 Diabetes Mellitus
- JOE A. FLORENCE, M.D., and BRYAN F. YEAGER, PHARM.D.
- University of Kentucky College of Medicine
- Lexington, Kentucky
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This article
exemplifies the AAFP 1999 Annual Clinical Focus on management and
prevention of the complications of diabetes.
Type 2 diabetes mellitus (formerly
called noninsulin-dependent diabetes) causes abnormal carbohydrate,
lipid and protein metabolism associated with insulin resistance and
impaired insulin secretion. Insulin resistance is a major contributor
to progression of the disease and to complications of diabetes. Type 2
diabetes is a common and underdiagnosed condition that poses treatment
challenges to family practitioners. The introduction of new oral
agents within the past three years has expanded the range of possible
combination regimens available for treating type 2 diabetes. Despite
the choice of pharmacologic agents, physicians must stress the
nonpharmacologic approaches of diet modification, weight control and
regular exercise. Pharmacologic approaches must be based on patient
characteristics, level of glucose control and cost considerations.
Combinations of different oral agents may be useful for controlling
hyperglycemia before insulin therapy becomes necessary. A stepped-care
approach to drug therapy may provide the most rational, cost-efficient
approach to management of this disease. Pharmaco-economic analyses of
clinical trials are needed to determine cost-effective treatment
strategies for management of type 2 diabetes.
Diabetes mellitus affects
approximately 16 million people in the United States and accounts for
about one sixth of all expenditures for health care.1
Ninety percent of patients with diabetes have type 2 diabetes (formerly
known as noninsulin-dependent diabetes) and often require oral agents
or insulin for glucose control. The mortality rate in patients with
diabetes may be up to 11 times higher than in persons without the
disease.1 Diabetes is a leading cause
of blindness, renal failure, and foot and leg amputations in adults.
Managed care and budgeted resources challenge clinicians to provide
comprehensive health care to patients with diabetes.
Within the past three years, the introduction of new oral agents has
prompted questions regarding the most cost-effective approach for
management of type 2 diabetes. Since pharmaco-economic data concerning
antidiabetic regimens are limited, clinicians must select the most
appropriate agent(s) based on patient characteristics, level of glucose
control and cost. A rational approach for managing patients with varying
stages of disease requires an understanding of features that lead to
disease progression, and a thorough review of the new oral agents for
the treatment of type 2 diabetes and the clinical and economic basis for
appropriate drug selection.
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TABLE 1
Criteria for the Diagnosis of Diabetes Mellitus and Impaired
Glucose Homeostasis
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| The rightsholder did not grant rights to reproduce
this item in electronic media. For the missing item, see the
original print version of this publication. |
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Disease Progression
Diabetes is a group of metabolic diseases with characteristic
hyperglycemia associated with defects in insulin secretion, insulin
action, or both. Type 1 diabetes (formerly known as insulin-dependent
diabetes) is characterized by beta cell destruction, usually leading to
absolute insulin deficiency. Its etiology is either immune mediated,
related to physical destruction of the pancreas (as in pancreatitis or
pancreatic cancer) or idiopathic. Type 2 diabetes presents as a spectrum
of metabolic abnormalities with prominent insulin resistance and
relative insulin deficiency.2 The
effect of diabetes is not limited to carbohydrate metabolism. Lipid and
protein metabolism play an important role in the progression of the
disease.3Abnormal glucose metabolism
accounts for poorly regulated biochemical processes that glycosylate
hemoglobin and other proteins and lipids throughout the body. The
progression of diabetes is caused by numerous metabolic events that
occur over a period of years. By controlling these metabolic events, the
progression of the disease may be slowed or stopped.
The prevalence of diabetes in persons 45 to 64 years of age is 7
percent, but the proportion increases significantly in persons 65 years
of age or older.4Certain minority
populations have even higher rates. Despite its high prevalence,
diabetes is largely underdiagnosed (Table 1).5
It is estimated that over 8 million people in the United States alone
are unaware that they have the disease.1
There is evidence that retinopathy begins to develop at least seven
years before the clinical diagnosis of type 2 diabetes is made.6
Patients with undiagnosed diabetes mellitus are at serious risk for
coronary heart disease, stroke and peripheral vascular disease, and have
a greater likelihood of dyslipidemia, hypertension and obesity.
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TABLE 2
Recommendations for Diabetes Screening of Asymptomatic Persons
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Timing of first test and repeat tests
Test at age 45; repeat every
three years for patients 45 years of age or older
Test before age 45; repeat more
frequently than every three years if patient has one or more of
the following risk factors:
- Obesity: >=20% of desirable
body weight or BMI >=27 kg per m2
- First-degree relative with
diabetes mellitus
- Member of high-risk ethnic
group (black, Hispanic, Native American, Asian)
- History of gestational
diabetes mellitus or delivering a baby weighing more than
4,032 g (9 lb)
- Hypertensive (>=140/90 mm Hg)
- HDL cholestrol level <=35 mg
per dL (0.90 mmol per L) and/or triglyceride level >=250 mg
per dL (2.83 mmol per L)
- History of IGT or IFG on
prior testing
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BMI=body mass index; HDL=high-density
lipoprotein; IGT=impaired glucose tolerance; IFG=impaired
fasting glucose.
Adapted with permission from Report of the
Expert Committee on the Diagnosis and Classification of Diabetes
Mellitus. Diabetes Care 1997;20:1183-97. |
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Criteria for diagnosing diabetes in asymptomatic, undiagnosed
patients are outlined in Table 2.5
These criteria are associated with the following factors: the steep rise
in the incidence of the disease after 45 years of age, the negligible
likelihood of developing any diabetic complications within three years
after a negative screening test, and knowledge of documented risk
factors for the disease (Table 3).7
Studies have defined the glycosylated hemoglobin A1c
(HbA1c) level above which the
likelihood of having or developing macrovascular or microvascular
disease increases. Because HbA1c and
fasting blood glucose (FBG) are the measurements of choice for
monitoring diabetes, decisions about when and how to implement treatment
strategies are based on these parameters.8
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TABLE 3
Major Risk Factors for Type 2 Diabetes Mellitus
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| Family history of
diabetes (parents or siblings with diabetes)
Obesity (>=120% over desired
body weight or BMI >=27 kg per m2)
Race/ethnicity (e.g., black,
Hispanic, native American, Asian American, Pacific Islander)
Age >=45 years
Previously identified IFG or IGT
Hypertension (>=140/90 mm Hg)
HDL cholesterol level <=35 mg
per dL (0.90 mmol per L) and/or a trigyceride level >=250 mg per
dL (2.83 mmol per L)
History of gestational diabetes
mellitus or delivery of babies over 4,032 g (9 lb) |
IFG=impaired fasting glucose; IGT=impaired
glucose tolerance; HDL=high-density lipoprotein.
Information from Screening for type 2
diabetes. Diabetes Care 1998;21(suppl 1):S20-2. |
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The National Diabetes Data Group9
developed the current classification and diagnosis of diabetes that is
used in the United States. Other diabetic states also may occur that
have etiologies differing from those of type 1 and type 2 diabetes.
These diabetic states include: genetic defects in beta cell function;
genetic defects in insulin action; diseases of the exocrine pancreas
(e.g., pancreatitis); trauma; cystic fibrosis; endocrinopathies (e.g.,
acromegaly, Cushing's syndrome, hyperthyroidism, pheochromocytoma);
drug- or chemical-induced; infection; uncommon forms of immune-mediated
diabetes; genetic syndromes (e.g., Down syndrome, Klinefelter's
syndrome, Turner's syndrome); and gestational diabetes mellitus.
Insulin resistance is defined as an impaired biologic response to
exogenous or endogenous insulin in the tissues. Insulin resistance and
impaired insulin secretion are the defining features of type 2 diabetes.
Patients with insulin resistance syndrome have a group of related
clinical and laboratory findings, including glucose intolerance, central
obesity, dyslipidemia, hypertension and altered fibrinolysis.10
Insulin resistance occurs because of defective insulin-mediated
glucose uptake and utilization, which reflects the inhibition of a
glucose transport. Both nonpharmacologic and pharmacologic therapies are
used to reduce insulin resistance. Nonpharmacologic approaches include a
low-calorie diet, weight loss and regular vigorous exercise.
Pharmacologic approaches include the use of metformin (Glucophage) and
troglitazone (Rezulin).
Since insulin resistance is hypothesized to be a major factor in the
development of type 2 diabetes, treatment of resistance may prevent or
delay the onset of diabetes. Presently, the Diabetes Prevention Program11
is under way to ascertain which treatment for insulin resistance may
help prevent or delay the onset of diabetes. These treatments include
intensive lifestyle changes (7 percent reduction of body weight through
caloric restriction and exercise) and use of metformin. Drug treatment
for primary prevention of diabetes is not currently warranted.
Insulin resistance is a major factor that contributes to
hyperglycemia. Macrovascular complications are strongly associated with
hyperinsulinemia that is due to insulin resistance. These complications
include cardiovascular, cerebrovascular and peripheral vascular
diseases. A number of mechanisms, independent of glucose metabolism, are
believed to accelerate the progression of diabetic complications.
Insulin-mediated biochemical pathways lead to enhanced vascular smooth
muscle proliferation, platelet adhesiveness and vasoconstriction.12
The risk of cardiovascular disease increases with diabetes and is
greater in patients with coexisting dyslipidemia. This combination of
disease states is associated with significant rates of morbidity and
mortality from cardiovascular events. Near-normal or improved glycemic
control has been shown to significantly diminish the risk of long-term
complications in patients with type 2 diabetes.13
The treatment of nonpregnant patients with "impaired fasting glucose"
should begin with lifestyle modification, including meal planning and
exercise. Initiation of pharmacologic therapy in these patients has not
been shown to improve their prognosis, and the use of insulin and
sulfonylureas may lead to complications of hypoglycemia.8
Oral Agents for Type 2 Diabetes
Sulfonylureas
With the labeling of tolbutamide (Orinase) by the U.S. Food and Drug
Administration in 1962, the sulfonylurea class of drugs quickly became
the mainstay of treatment for type 2 diabetes. Although newer agents
have recently entered the marketplace, sulfonylureas still play a
primary role in pharmacologic management of type 2 diabetes. Patients
who respond best to treatment with sulfonylureas include those with a
diagnosis of type 2 diabetes before 40 years of age, duration of disease
less than five years before initiation of drug therapy and a fasting
blood glucose level of less than 300 mg per dL (16.7 mmol per L).14
Approximately two thirds of patients who begin therapy with a
sulfonylurea respond, although up to 20 percent of them eventually
require additional medication. Few patients with uncontrolled diabetes
receive clinical benefit when switched from one sulfonylurea agent to
another.14 The use of agents with a
longer half-life (e.g., chlorpropamide [Diabinese]) in the elderly and
in patients with renal impairment is discouraged because the risk of
hypoglycemia is increased.
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| Insulin
resistance may be decreased with dietary modification, weight
loss and exercise; use of metformin and the thiazolidinediones
may also reduce insulin resistance. |
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Metformin
Metformin is a biguanide agent that lowers blood glucose primarily by
decreasing hepatic glucose output and reducing insulin resistance.
Metformin is used as monotherapy or in combination with sulfonylureas
for management of type 2 diabetes. When used as monotherapy, metformin
does not cause hypoglycemia and is thus termed an "antihyperglycemic."
The use of metformin is contraindicated in patients with renal
insufficiency (i.e., a serum creatinine level of 1.5 mg per dL [130 µmol
per L] in men and 1.4 mg per dL [120 µmol] in women, or abnormal
creatinine clearance) or acute or chronic metabolic acidosis. Metformin
should be temporarily withheld before any procedure involving
intravascular administration of iodinated contrast media. Normal renal
function should be confirmed 48 hours after the procedure before
restarting metformin therapy. There is no known reason to discontinue
metformin therapy during other parenteral contrast studies.
Extreme caution should be used in patients with severe hepatic
dysfunction, hypoxemic states (e.g., severe chronic obstructive
pulmonary disease, congestive heart failure), moderate to severe illness
and excessive alcohol intake. In these patients, the use of metformin
may contribute to the development of lactic acidosis, a condition that
is fatal in about 50 percent of patients who develop it (one episode per
100,000 patient-years).15 Cimetidine (Tagamet)
decreases the renal clearance of metformin and may potentiate its
effects. Patients receiving oral anticoagulant therapy and metformin may
require a higher dosage of warfarin (Coumadin) to achieve a therapeutic
antithrombotic effect.16 Hemogloblin,
hematocrit, red blood cell indexes and renal function should be
monitored at least annually in patients taking metformin.
Alpha-Glucosidase Inhibitors
Alpha-glucosidase inhibitors, such as acarbose (Precose) and miglitol (Glyset),
are indicated as monotherapy or in combination with sulfonylureas for
management of type 2 diabetes. These agents inhibit the breakdown of
complex carbohydrates and delay the absorption of monosaccharides from
the gastrointestinal tract.17 Acarbose
and miglitol should be titrated over two to three weeks to minimize
flatulence and other gastrointestinal side effects that commonly lead to
discontinuation of these agents. Alpha-glucosidase inhibitors are
contraindicated in patients with inflammatory bowel disease, partial
intestinal obstruction, a predisposition to intestinal obstruction,
colonic ulceration and other gastrointestinal disorders.17
Dose-dependent hepatotoxicity is associated with this drug class, so
liver function tests should be carefully monitored in patients receiving
higher dosages of these medications (e.g., more than 50 mg three times
daily). Transaminase elevations are reversible with discontinuation of
the drug and are often asymptomatic. Serum transaminase levels should be
checked every three months for the first year patients take the
medication and periodically thereafter. Drugs that are susceptible to
binding with other agents (e.g., cholestyramine [Questran]) should be
taken two to four hours apart from alpha-glucosidase inhibitors to avoid
drug interactions. Intestinal absorbents and digestive enzyme
preparations should not be administered with acarbose.
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| Near-normal or
improved glycemic control has been shown to significantly
diminish the risk of microvascular complications in patients
with type 2 diabetes mellitus. |
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Troglitazone
The thiazolidinediones are a unique drug class of "insulin sensitizers"
that promote skeletal muscle glucose uptake.18
Troglitazone is the first agent of this drug class to be introduced in
the U.S. market and, like metformin, it reduces insulin resistance.
Troglitazone is beneficial in patients requiring large daily amounts of
insulin (more than 30 units per day) whose diabetes is still
uncontrolled. A reduction of up to 50 percent in total daily insulin
dosage is possible with drug titration. Troglitazone is also effective
when used in combination with other oral agents,19
thereby potentially delaying the need to start insulin therapy.
The U.S. Food and Drug Administration recently ruled that
troglitazone should only be used in combination with other diabetic
therapies. The effectiveness of oral contraceptives may be decreased
with troglitazone administration. Over 150 case reports of
hepatotoxicity have been reported with troglitazone, so liver function
must be monitored every month for the first eight months of treatment
and every other month for four months thereafter.18
Periodic transaminase measurements should be obtained as long as the
patient is taking troglitazone.
Repaglinide
Repaglinide (Prandin) is a benzoic acid derivative and the first of the
non-sulfonylurea meglitinides introduced in early 1998. The mechanism of
action and side effect profile of repaglinide are similar to those of
the sulfonylureas.15 This agent has a
rapid onset of action and should be taken with meals two to four times
daily. Repaglinide is a suitable option for patients with severe sulfa
allergy who are not candidates for sulfonylurea therapy. The drug is
used as monotherapy or in combination with metformin. It should be
titrated cautiously in elderly patients and in those with renal or
hepatic dysfunction.
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TABLE 4
Dose-Response of Oral Agents for Type 2 Diabetes Mellitus
|
Agent
|
Average FBG reduction (%)
|
Average PPG reduction (%)
|
Average HbA1c reduction (%)
|
|
Sulfonylureas |
25 to
40 |
20 |
2.0 |
|
Alpha-glucosidase inhibitors* |
10 to
20 |
40 to
45 |
0.5
to 1.5 |
|
Metformin (Glucophage)* |
20 to
40 |
25 |
1.5
to 2.0 |
|
Troglitazone (Rezulin)* |
20 |
25 |
1.0
to 1.5 |
FBG=fasting blood glucose; PPG=postprandial
glucose; HbA1c=glycosylated hemoglobin A1c.
*--Combined with another oral agent or
insulin.
Information from references 15 through 17.
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TABLE 5
Goals of Therapy for Patients with Diabetes Mellitus*
|
Biochemical index
|
Nondiabetic value
|
Goal value
|
When additional action is suggested
|
|
Preprandial glucose measurement† |
<110
mg per dL (6.1 mmol per L) |
80 mg
per dL (4.4 mmol per L) to 120 mg per dL (6.7 mmol per L) |
<80
mg per dL (4.4 mmol per L) or >140 mg per dL (7.8 mmol per L) |
|
Bedtime glucose measurement† |
<120
mg per dL (6.7 mmol per L) |
100
mg per dL (5.6 mmol per L) to 140 mg per dL (7.8 mmol per L) |
<100
mg per dL (5.6 mmol per L) or >160 mg per dL (8.9 mmol per L) |
| HbA1c
(%) |
<6 |
<7 |
>8 |
HbA1c=glycoslylated hemoglobin.
*--The values shown in this table are by
necessity generalized to the entire population of persons with
diabetes. Patients with co-morbid 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,
co-management with a diabetes team, referral to an
endocrinologist, change in pharmacologic therapy, initiation of
or increase in self-monitored blood glucose testing, or more
frequent contact with the patient. HbA1c is
referenced to a nondiabetic range of 4.0 to 6.0 percent.
†--Measurement of capillary blood glucose.
Information from Standards of medical care
for patients with diabetes mellitus. Diabetes Care 1998;21(suppl
1):S23-31. |
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Treatment Rationale
All treatment strategies should emphasize cardiovascular risk
reduction, focusing particularly on hypertension control, smoking
cessation and correction of dyslipidemia. Diet, exercise and weight
reduction should be the cornerstone of management. Before selecting a
medication to improve control of diabetes, the family physician should
understand the comparative glucose-lowering effects of available agents.
The dose-response for the oral agents on levels of FBG, postprandial
glucose and HbA1c is described in
Table 4.16-18 The goals of therapy
for type 2 diabetes are outlined in Table 5.20
Few clinical trials have been conducted to evaluate the possibility
of a "ceiling effect" with select antidiabetic agents. A dose-dependent
reduction in HbA1c was observed with
glimepiride (Amaryl) in one clinical trial.21
Splitting the total daily dosage of sulfonylurea into two separate doses
may be necessary to achieve optimal glycemic control in most patients on
medium to high daily dosages of these agents. Patients with type 2
diabetes become less responsive over time to one agent alone and
frequently require combination therapy to adequately control their
disease.
The current approach to management of drug therapy in patients with
type 2 diabetes is to begin insulin therapy if a combination of two oral
agents fails to provide adequate glycemic control. For every 10 units of
insulin administered, an average of 1 kg of weight may be gained.22
This weight gain, associated with the lipotrophic effect of insulin,
promotes greater insulin resistance in patients with severe disease. The
result of escalating doses of insulin is a perpetual cycle of weight
gain and uncontrolled diabetes. With the advent of the newer oral
agents, combination therapy may delay insulin use in patients who
traditionally would require insulin early in the course of the disease.
Reasonable combinations of oral agents based on mechanism of action
include sulfonylurea plus metformin, sulfonylurea plus an alpha-glucosidase
inhibitor, sulfonylurea plus troglitazone, repaglinide plus metformin,
troglitazone plus metformin, insulin plus metformin, and insulin plus
troglitazone.
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| Patients with
type 2 diabetes mellitus often become less responsive to a
single oral agent over time, and combination therapy may be
needed for adequate control of blood glucose levels. |
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|
Daily home glucose monitoring is strongly encouraged in all patients
with diabetes who undergo therapy with insulin or oral agents. Patients
with uncontrolled disease and those requiring medication adjustment need
more intensive monitoring. The frequency and timing of glucose
monitoring should be individualized for each patient. The optimal
frequency of self-monitoring of blood glucose in patients with type 2
diabetes is not known, but monitoring should be performed often enough
to facilitate reaching treatment goals. Efforts should be made to
substantially increase appropriate use of self-monitoring, providing
both the patient and the practitioner with substantial information
necessary to achieve glycemic goals. The family practitioner should
negotiate appropriate monitoring for patients with finger soreness,
hectic lifestyles or more stable diabetes.
A stepped-care approach to drug therapy provides a rational,
effective method of disease management. All oral agents available for
treatment of type 2 diabetes are indicated for use as monotherapy after
diet, exercise and weight reduction have failed to control
hyperglycemia. Currently, there is no clinical advantage in selecting a
sulfonylurea, metformin or insulin as initial therapy, although certain
causes of hyperglycemia or patient characteristics may make one
preferable to another (Figure 1). The United Kingdom Prospective
Diabetes Study (UKPDS) showed a similar reduction in microvascular
complications in patients treated with these drug classes. No difference
in cardiovascular outcomes was apparent.13
Because alpha-glucosidase inhibitors and troglitazone were not evaluated
in the UKPDS, it is not known how these agents affect diabetes-related
complications.
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TABLE 6
Components of Initial Office Visit for Patients with Diabetes
Mellitus
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Medical history |
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Symptoms, laboratory results related to diagnosis
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Nutritional assessment, weight history |
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Previous and present treatment plans |
|
Medications |
|
Medical nutrition therapy |
|
Self-management training |
|
Self-management blood glucose results |
|
Current treatment program |
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Exercise history |
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Acute complications |
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History of infections |
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Chronic diabetic complications |
|
Medication history |
|
Family history |
|
Risk factors for coronary heart disease |
|
Psychosocial/economic factors |
|
|
Physical examination |
|
Height and weight |
|
Blood pressure |
|
Ophthalmoscopic examination |
|
Thyroid palpation |
|
Cardiac examination |
|
Evaluation of pulses |
|
Foot examination |
|
Skin examination |
|
Neurologic examination |
|
Oral examination |
|
Sexual maturation (if peripubertal) |
|
|
Laboratory evaluation |
|
Fasting plasma glucose (optional) |
|
Glycohemoglobin |
|
Fasting lipid profile |
|
Serum creatinine |
|
Urinalysis |
|
Urine culture (if indicated) |
|
Thyroid function tests (if indicated) |
|
Electrocardiogram (adults) |
| |
|
Management plan |
|
Short- and long-term goals |
|
Medications |
|
Medical nutrition therapy |
|
Lifestyle changes |
|
Self-management education |
|
Monitoring instructions |
|
Annual referral to eye specialist |
|
Specialty consultations (as indicated) |
|
Agreement on continuing support/follow-up |
|
Information from Standards of medical care
for patients with diabetes mellitus. Diabetes Care 1998;21(suppl
1):S23-31. |
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|
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TABLE 7
Components of Follow-Up Visits for Patients with Diabetes
Mellitus
|
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Contact frequency
|
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Daily for initiation of insulin
or change in regimen |
|
Weekly for initiation of oral
glucose-lowering agent(s) or change in regimen |
|
Routine diabetes visits
|
|
Quarterly or more often for
patients who are not meeting goals |
|
Semi-annually for other
patients |
| |
|
Medical history (assessment
of treatment regimen) |
|
Frequency/severity of
hypoglycemia or hyperglycemia |
|
SMBG results |
|
Patient regimen adjustments
|
|
Adherence problems |
|
Lifestyle changes |
|
Symptoms of complications
|
|
Other medical illnesses
|
|
Medications |
|
Psychosocial issues
|
| |
|
Physical examination
|
|
Physical examination annually
|
|
Dilated eye examination
annually |
|
Every regular diabetes visit
|
| |
Weight |
| |
Blood pressure |
| |
Previous abnormalities on the physical examination
|
| |
Foot examination |
|
|
Laboratory evaluation
|
|
Hemoglobin A1c
|
| |
Quarterly if treatment changes or patient is not meeting
goals |
| |
Twice per year if stable |
|
Fasting plasma glucose
(optional) |
|
Fasting lipid profile annually
|
|
Urinalysis for protein annually
|
|
Microalbumin measurement
annually (if urinalysis is negative for protein)
|
| |
|
Management plan review
|
|
Each visit |
| |
Short- and long-term goals |
| |
Medications |
| |
Glycemia |
| |
Frequency/severity of hypoglycemia |
| |
SMBG results |
| |
Complications |
| |
Control of dyslipidemia |
| |
Blood pressure |
| |
Weight |
| |
Medical nutrition therapy |
| |
Exercise regimen |
| |
Adherence to self-management training |
| |
Follow-up of referrals |
| |
Psychosocial adjustments |
|
Annually |
| |
Knowledge of diabetes |
| |
Self-management skills |
|
SMBG=self-monitoring of blood glucose.
Information from Standards of medical care
for patients with diabetes mellitus. Diabetes Care 1998;21(suppl
1): S23-31. |
 |
|
When possible, sulfonylureas should be prescribed as initial therapy
in nonobese patients since they are less expensive than the newer oral
agents. Metformin is an excellent initial agent for obese patients
(i.e., those greater than 120 percent of ideal body weight) or as add-on
therapy in patients whose disease is not controlled with sulfonylurea
therapy. An alpha-glucosidase inhibitor or troglitazone may be an
alternative to a sulfonylurea or metformin as add-on therapy in patients
with uncontrolled disease or significant renal dysfunction.
Patients generally require some form of insulin treatment if their
diabetes cannot be managed adequately with maximum dosages of two oral
agents. The use of three oral agents in combination to control blood
glucose is of limited benefit. Since metformin and troglitazone are
currently the only antidiabetic medications that decrease insulin
resistance, they are logical choices for use with insulin regimens. In
patients whose diabetes remains uncontrolled even with moderate daily
dosages of insulin (i.e., more than 30 units per day), metformin and
troglitazone are effective in reducing insulin requirements and
improving glycemic control. Currently, no pharmaco-economic analyses
have been performed to evaluate the cost-effectiveness of various
antidiabetic regimens.
Recommended components of initial and follow-up office visits for
patients with diabetes are outlined in Tables 6 and 7.20
Each year members of two different
medical faculties develop articles for "Practical Therapeutics." This
article is one in a series coordinated by the Department of Family
Practice at the University of Kentucky College of Medicine, Lexington.
Guest editors of the series are Bryan F. Yeager, Pharm.D., Thomas
Armsey, M.D., and Samuel C. Matheny, M.D., M.P.H.
The Authors
JOE A. FLORENCE, M.D.,
is an associate professor in the department of family practice at the
University of Kentucky College of Medicine and director of the East
Kentucky Family Practice Residency Program in Hazard, Ky. He received
his medical degree from Virginia Commonwealth University Medical College
of Virginia, Richmond, and served a residency in family practice at
Roanoke (Va.) Memorial Hospitals.
BRYAN F. YEAGER, PHARM.D.,
is an assistant professor in the department of family practice and the
division of pharmacy practice and science at the University of Kentucky
Colleges of Medicine and Pharmacy. He received his doctor of pharmacy
degree from the University of Texas at Austin, where he also completed a
postdoctoral residency in primary care and geriatrics.
Address correspondence to Bryan F.
Yeager, Pharm.D., K302 Kentucky Clinic, Lexington, KY 40536-0284.
Reprints are not available from the authors.
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- Report of the Expert Committee on the Diagnosis
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1):S5-19.
- Uusitupa MI, Niskanen LK, Siitonen O, Voutilainen
E, Pyorala K. Ten-year cardiovascular mortality in relation to risk
factors and abnormalities in lipoprotein composition in type 2
(non-insulin-dependent) diabetic and non-diabetic subjects.
Diabetologia 1993;36:1175-84.
- Clark CM Jr. How should we respond to the
worldwide diabetes epidemic? [Editorial] Diabetes Care 1998;21:475-6.
- Report of the Expert Committee on the Diagnosis
and Classification of Diabetes Mellitus. Diabetes Care
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