816
U N I T 9
Endocrine System
glycemic control, maintenance of blood pressure control
(<140/80 mm Hg), prevention or reduction in the level
of proteinuria (using angiotensin-converting enzyme
inhibitors or angiotensin receptor blockers, or protein
restriction in selected patients), treatment of hyperlipid-
emia, and smoking cessation in people who smoke.
11,57
Smoking increases the risk of CKD in both persons with
and without diabetes. People with type 2 diabetes who
smoke have a greater risk of increased urinary albu-
min excretion, and their rate of progression to CKD is
approximately twice as rapid as in those who do not
smoke.
11
Diabetic Retinopathies
Diabetes is the leading cause of acquired blindness in
the United States.
58,59
Although people with diabetes are
at increased risk for development of cataracts and glau-
coma, retinopathy is the most common pattern of eye
disease. Diabetic retinopathy is estimated to be the most
frequent cause of newly diagnosed blindness among
Americans between the ages of 20 and 74 years.
59
Diabetic retinopathy is characterized by abnormal
retinal vascular permeability, microaneurysm forma-
tion, neovascularization and associated hemorrhage,
scarring, diabetic macular edema, and retinal detach-
ment
59
(see Chapter 38). Twenty years after the onset
of diabetes, nearly all people with type 1 diabetes and
more than 60% of people with type 2 diabetes have
some degree of retinopathy. Pregnancy, puberty, and
cataract surgery can accelerate these changes.
59
Risk fac-
tors associated with diabetic retinopathy are similar to
those for other complications. Among the suggested risk
factors associated with diabetic retinopathy are poor
glycemic control, elevated blood pressure, dyslipidemia,
and smoking. The strongest case for control of blood
glucose comes from the DCCT/EDIC and UKPDS stud-
ies, which demonstrated a reduction in retinopathy with
improved glucose control.
49,50
Because of the risk of retinopathy, it is important that
people with diabetes have regular dilated eye examina-
tions. The recommendation for follow-up examinations
is based on the type of examination that was done and
the findings of that examination. People with persis-
tently elevated glucose levels or proteinuria should be
examined yearly.
59
Women who are planning a preg-
nancy should be counseled on the risk of development
or progression of diabetic retinopathy. Women with dia-
betes who become pregnant should be followed closely
throughout pregnancy. This does not apply to women in
whom GDM develops because such women are not at
risk for development of diabetic retinopathy.
People with macular edema, moderate to severe non-
proliferative retinopathy, or any proliferative retinopa-
thy should receive the care of an ophthalmologist who is
knowledgeable and experienced in the management and
treatment of diabetic retinopathy. Methods used in the
treatment of diabetic retinopathy include the destruction
and scarring of the proliferative lesions with laser pho-
tocoagulation. The use of antagonists to growth factors
(e.g., vascular endothelial growth factor) administered
by intra-vitreal injections also play an important role in
the management of diabetic retinopathy, and are con-
sidered the gold-standard therapy in diabetic macular
edema.
Macrovascular Complications
Diabetes mellitus is a major risk factor for atheroscle-
rotic coronary artery disease, cerebrovascular disease,
and peripheral vascular disease. The prevalence of these
macrovascular complications is increased two- to four-
fold in people with diabetes.
Multiple risk factors for macrovascular disease,
including obesity, hypertension, hyperglycemia, hyper-
insulinemia, hyperlipidemia, altered platelet function,
endothelial dysfunction, systemic inflammation (as
evidenced by increased CRP), and elevated fibrinogen
levels, frequently are found in people with diabetes.
There appear to be differences between type 1 and type
2 diabetes in terms of duration and development of
macrovascular disease, with type 2 diabetics more com-
monly manifesting macrovascular disease at the time of
diagnosis. This greater prevalence has been attributed to
the associated cardiovascular risk factors that are part
of the metabolic syndrome and which may have been
present for many years before the diagnosis of type 2
diabetes.
19,20
Aggressive management of cardiovascular risk fac-
tors should include smoking cessation, lifestyle changes
including weight loss, and measures to control blood
lipids, hypertension, and blood glucose, as appropri-
ate.
19
Antiplatelet agents (aspirin or clopidogrel) may
be prescribed to reduce the threat of blood clots. If
treatment is warranted for peripheral arterial disease,
the peroneal arteries between the knees and ankles
commonly are involved in diabetes, making revascular-
ization difficult.
Diabetic Foot Ulcers
Foot problems are common among people with diabetes
and may become severe enough to cause ulceration, infec-
tion, and, eventually, the need for amputation.
60,61
Foot
problems have been reported as the most common com-
plication leading to hospitalization among people with
diabetes. They represent the effects of neuropathy and
vascular insufficiency. Approximately 60% to 70% of
people with diabetic foot ulcers have neuropathy without
vascular disease, 15% to 20% have vascular disease, and
15% to 20% have neuropathy and vascular disease.
60
Distal symmetric neuropathy is a major risk factor
for foot ulcers. People with sensory neuropathies have
impaired pain sensation and often are unaware of the
constant trauma to the feet caused by poorly fitting
shoes, improper weight bearing, hard objects or peb-
bles in the shoes, or infections such as athlete’s foot.
Neuropathy may prevent people from detecting pain;
they are unable to adjust their gait to avoid walking on
an area of the foot where pressure is causing trauma
and necrosis. Motor neuropathy with weakness of the
intrinsic muscles of the foot may result in foot deformi-
ties, which lead to focal areas of high pressure. When
