Risk Factors For PAD
in Diabetes
Edward Fasolino, MD
Assistant Professor
Department of Family Medicine
Scott and White Belton Clinic
Texas A and M University-Health Science Center
Diabetic Foot Update
December 3, 2011
Peripheral Arterial
Disease (PAD)
•  PAD is a
narrowing of
the peripheral
arteries, most
commonly in
the arteries of
the pelvis and
legs
Disease Burden
•  AHA 2007 Update estimates 8 million
Americans have PAD
•  PAD affects up to 20% of those >65 yo
•  <10% have intermittent claudication
•  <25% of those affected are under
treatment
•  Critical Limb Ischemia-most common cause
of amputation (>100,000 per year)
At Risk Individuals for PAD
•  Epidemiological Evidence
•  Age <50 yo with DM and at least one other risk
factor (smoking, dyslipidemia, HTN, etc)
•  Age 50-69 with history of DM or smoking
•  Age >70
•  Leg symptoms with exertion or ischemic rest pain
•  Abnormal pulse exam in lower extremity
•  Known atherosclerotic coronary, carotid, or renal
artery disease
Intermittent Claudication
•  Intermittent-”sporadic”
claudication-”limping”
•  <10% with PAD have it
•  ~40% have no symptoms at all
•  ~50% have variety of other
leg symptoms
•  Burning or aching
•  Cold feet
•  Color changes (red or pale)
•  Toe or foot sores that
won’t heal
Risk Factors
•  Unmodifiable (Fixed)
•  Modifiable
Unmodifiable Risk
Factors
• 
• 
• 
• 
Age
Family or Personal History of PAD
Cardiovascular Disease/Stroke
Race
Age
•  Why is age a risk factor?
•  Atherosclerosis is a progressive disease
•  The longer you live, the more you have
•  Other risk factors multiply
•  HTN
•  Obesity
•  Inactivity
Age
•  Up to 20% of those >65 yo have PAD
•  13% Americans are >65 yo (2010 Census)
•  5% of men and 7% of women are >80 yo
•  Life expectancy of baby born this year
•  Male 75.6
•  Female 80.7
•  Get older or die!
Family or Personal
History of PAD
•  Genetic factors
•  Lipidemias
•  Diabetes
•  HTN
Inheritance
•  Lipidemias
•  Familial Hypercholesterolemia
•  Heterozygous autosomal dominant
disease
•  Early and advanced atherosclerosis
•  5-10 times risk for PAD
Inheritance-Diabetes
•  Type 1 and Type 2 both have some degree
of heritability
•  Monozygotic twins > dizogotic twins
•  Type 1 inheritance > Type 2
•  Type 2 accounts for > 90% of diabetes
•  Estimates of 26% due to genetics
Diabetes
•  Early and advanced atherosclerosis
•  Other risk factors often present
•  HTN-Primary and Secondary
•  Obesity
•  Inactivity
Hypertension
•  JNC VII
•  Normal-Systolic <120, diastolic <80
•  Prehypertension-Systolic 120-139, diastolic
80-90
•  Stage 1-Systolic 140-159, diastolic 90-99
•  Stage 2-Systolic >160, diastolic >100
Inheritance-HTN
•  Primary Hypertension
•  30-40% thought to be inherited
•  Secondary Hypertension
•  Varies due to cause
•  Renal artery disease
•  Atherosclerosis
•  Endocrine causes
Personal History of
PAD
•  Recurrence rate high
•  Ipsilateral or contralateral
•  Proximal or distal
•  Unless significant risk factors are changed
Framingham Offspring
Study
•  Started in 1971
•  Family History accounts for approximately
21% of PAD risk
•  Heritability of PAD risk similar amongst
races
Cardiovascular Disease
•  Disease in any artery,
all arteries
presupposes disease in
•  Myocardial infarctions
•  Aortic aneurysms
•  Renal artery disease
•  Cerebrovascular disease-Stroke
•  Peripheral Arterial Disease
Race
•  Blacks have higher risk of PAD than Hispanics,
which have a higher risk than non-Hispanic
whites
•  NHANES (National Health and Nutrition
Examination Survey-2004) suggests some of the
racial difference is from other factors
(environmental, socioeconomic status, diet,
etc)
Modifiable Risk Factors
•  Diabetes mellitus (assumed for this lecture)
•  Cigarette smoking
•  Obesity
•  Physical inactivity
•  High blood cholesterol
•  High blood pressure
Cigarette Smoking
•  80-90% of PAD sufferers are current or
former smokers
•  2009-~46 million smokers (20% of adults)
•  23% of males, 17% of females smoke
•  Whites>blacks>hispanics>asians
•  ~430,000 deaths per year due to smoking
Cigarette Smoking
•  Highest risk factor in PAD
•  Two to 25 times greater risk with any
other risk factor
•  Dose response-both packs per day, and
pack-years
•  Second hand smoke a risk factor based
on dose
Nicotine
•  Nitric oxide release impaired
•  Atherogenic
•  Vasoconstrictor
•  Thrombogenic
Obesity
•  Independent risk factor from diabetes
•  Dose effect
•  Increasing incidence
•  Inflammatory factors
•  Apple vs pear
Apple vs. Pear
•  Visceral fat vs. SubQ fat
•  Atherogenic
•  Insulin resistance
•  HTN
•  Questioned
Obesity
•  Impairs activity
•  Raises cholesterol, triglycerides, lowers
HDL
•  Worsens venous stasis
•  Edema
Physical Inactivity
•  Sedentary lifestyle is bad
•  Physical activity definition-150 minutes of
moderate activity per week
•  Approximately 1.9 million extra deaths per year
due to inactivity worldwide
•  Physical inactivity results in 20-30% increase in all
cause mortality
•  Risk factor in PAD, CAD, stroke, depression,
osteoporosis
High Cholesterol
•  Elevated Total and LDL
•  Low HDL <40
significantly raises risk
•  Elevated triglycerides
•  Atherogenic
Risk Thresholds
•  NCEP ATP III-Diabetes considered a CHD
equivalent
•  Therefore LDL >100 considered high risk
•  Triglycerides >200
•  HDL <40 men, 50 women
•  Every 10 mg/dl increase in total
cholesterol, raises PAD risk by 5-10%
Hypertension
•  Independent PAD risk factor
•  Atherogenic
•  Up to 30% of adults have HTN
•  70-80% of those with PAD have HTN
•  Women with HTN, 4-5 X’s more likely to
develop PAD High Blood Pressure
•  Goals in Diabetics
•  Systolic <130
•  Diastolic <80
HTN Risk
•  Uncontrolled
•  Raises risk of stroke 35-40%
•  Raises risk of MI 20-25%
•  Raises risk of dying of heart disease 25%
•  Raises risk of diabetes complication
Summary of Risk Factors
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Unmodifiable
• 
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Age
Personal or Family History of PAD
Cardiovascular Disease
Race
Modifiable
• 
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Diabetes
Cigarette smoking
Obesity
Inactivity
Hyperlipidemia
HTN