Prevention ofDiabetic Foot Ulcers and

Lower Extremity Amputation

Barry Stults, MD

Scott A. Clark, DPM

Thomas Miller, MD

© 2007. American College of Physicians. All rights reserved.

This content has been excerpted from the ACP Clinical Skills Module, "Diabetic Foot Ulcers."

For more information visit: http://www.acponline.org/clinicalskills/

“…the enormity of the global burden of diabetic foot disease…this much neglected, but potentially devastating, complication of a disease that is reaching epidemic proportions…Someone, somewhere, loses a leg because of diabetes every 30 seconds of everyday…”

Lancet. 2005;366:1674

Case Study

64-year-old obese man

Type 2 DM (15 yrs) BP (18 yrs) Dyslipidemia (18 yrs) CABG (10 yrs ago) Claudication (today; 25 yds)

Insulin/Metformin/Statin/ACEI/HCTZ/ASA

“Sore on my left foot, Doc”

Case Study (continued)

Clinical evaluation of heel ulcer: Probe reached bone Extensive subcutaneous abscess

MRI: extensive osteomyelitis

ABI: 0.2

Angiography: Inoperable severe vascular disease

Uncontrolled infection

Amputation necessary

Amputations in Diabetes

Common:

U.S.A. – 80,000 amputations/year (2002)

Costly:

$60,000/amputation

$2 billion total costs annually

Lancet. 2005;366:1719

Diabetes Care. 2004;27:1598

Diabetes Care. 2003;26:495

50% ofamputations

50% of patients

50% of patients

Tragic “Rule of 50”

Transfemoral/transtibial level

2nd amputation in 5 years

Die in 5 years

Clinical Care of the Diabetic Foot, 2005

Tragic “Rule of 15”

15% of diabetes Foot ulcer in lifetimepatients

15% of foot ulcers Osteomyelitis

15% of foot ulcers Amputation

Clinical Care of the Diabetic Foot, 2005

Team Care

Identification of high-risk patients

Detection of early problems

Educate/motivate self-care behaviors

Prophylactic nail/skin care

Therapeutic footwear

Prompt, multidisciplinary treatment of ulcers

Lancet. 2005;366:1676

Team Care Reduces Ulcers/Amputations

50%-80% reductions in ulcers/amputations

Economic modeling studies

Cost-effective if 25%-40% reduction in ulcer rate Cost-saving if > 40% reduction in ulcer rate

Lancet. 2005;366:1719

Diabetes Care. 2004;27:901

Causal Pathways for Foot Ulcers

Neuropathy

Deformity

ULCER

% Causal Pathways

Neuropathy: 78%

Minor trauma: 79%

Deformity: 63%

Behavioral ?

Diabetes Care. 1999; 22:157

Poor self-foot care

Minor Trauma

- Mechanical (shoes)

- Thermal

- Chemical

Detecting Feet-at-risk

History: Prior amputation or foot ulcer Peripheral artery disease (PAD)

Exam: Insensate Foot deformities Absent pulses Prolonged venous filling time Reduced ABI Pre-ulcerative cutaneous pathology

Arch Intern Med. 1998;158:157

Risk Stratify for Ulcer Risk

Diabetes Care. 2001;24:1442

Diabetes Metab. 2003;29:261

Risk LevelFoot Ulcer

%/yr% Office Patients(diabetes clinics)

3: Prior amputationPrior ulcer

28.1%18.6%

7%

2: Insensate andfoot deformity orabsent pedalpulses

6.3% 10%

1: Insensate 4.8% 17%-30%

0: All normal 1.7% 66%

Annual Diabetic Foot Exams

TotalPrivate

InsuranceMedicaid-Medicare VA Uninsured

% with footexam in past year

63 64 65 84* 48*

Health Services Research. 2005;40:361

*p < 0.01

2000 Behavioral Risk Factor Surveillance System, CDC

Physical Examination of the Feet

in Persons with Diabetes

Sensory Neuropathy in Diabetes

Loss of protective sensation in feet

Detect with 5.07/10-g Semmes-Weinstein monofilament

50% of insensate patients have no symptoms

Diabetes Care. 2006;29(Suppl 1):S24

Diabetes Care. 2004;27:1591

Monofilament Testing

Test characteristics:

Negative predictive value = 90%-98% Positive predictive value = 18%-36%

Prospective observational study:

80% of ulcers and 100% of amputations occur in insensate feet

Superior predictive value vs. other test modalities

J Fam Pract. 2000;49:S30

Diabetes Care. 1992;15:1386

Using the Monofilament

Demonstrate on forearm or hand

Place monofilament perpendicular to test site

Bow into C-shape for 1 second

Test 4 sites/foot

Heel testing does not predict ulcer

Avoid calluses, scars, and ulcers

Monofilament Testing Tips

Insensate at 1 site = insensate feet

Falsely insensate with edema, cold feet

Test annually when sensation normal

Use monofilament < 100 times day Replace if bent Replace every 3 months

Vibration Testing

Biothesiometer

Best predictor of foot ulcer risk

128-Hz tuning fork at halluces

Equivalent to 10-g monofilament Newly recommended by ADA

Diabetes Care. 2006;29(Suppl 1):S25

Diabetes Res Clin Pract. 2005;70:8

Motor Neuropathy and Foot Deformities

Hammer toes

Claw toes

Prominent metatarsal heads

Hallux valgus

Collapsed plantar arch

Hammer Toes

Claw Toes

© 2002 American Diabetes AssociationFrom The Uncomplicated Guide to Diabetes ComplicationsReprinted with permission from The American Diabetes Association

© 2002 American Diabetes AssociationFrom The Uncomplicated Guide to Diabetes ComplicationsReprinted with permission from The American Diabetes Association

Hallux Valgus

Boulton, et al. Guidelines for Diagnosis of Outpatient Management of Diabetic Peripheral Neuropathy. Diabetic Medicine 1998, 15:508-512

Pre-ulcer Cutaneous Pathology

Persistent erythema after shoe removal

Callus

Callus with subcutaneous hemorrhage

Fissure

Interdigital maceration, fungal infection

Nail pathology

AJM Boulton, H Connor, PR Cavanagh, The Foot in Diabetes, 2002

Pre-ulcer

Peripheral Artery Disease

Prevalence (ABI < 0.9): 10%-20% in type 2 diabetes at diagnosis 30% in diabetics age 50 years 40%-60% in diabetics with foot ulcer

Complications: Claudication Associated coronary and cerebral vascular

disease Delayed ulcer healing

Diabet Med. 2005;22:1310

Diabetes Care. 2003;26:3333

Pedal Pulse Examination

Absent pedal pulses predicts severe PAD

Absence of a single pedal pulse does not predict PAD

Presence of pedal pulses does not rule out PAD!

Arch Intern Med. 1998;158:1357

Diabetes Care. 2003;26:3333

Venous Filling Time

Sitting: Locate pedal vein bulging above skin

Supine: Elevate leg to 45° for 1 minute

Sitting: Check time to pedal vein bulging

J Clin Epidemiol. 1997;50:659

Arch Intern Med. 1998;158:1357

Venous Filling Time Interpretation

Filling Time

Normal <20 sec

Abnormal/collaterals 20-40 sec

Severe PAD >40 sec

Filling time > 20 sec predicts ABI < 0.5 Sensitivity, 22%; Specificity, 94%; LR, 3.9

J Clin Epidemiol. 1997;50:659

Arch Intern Med. 1998;158:1357

Adapted from: Norman PE, Eikelboom JW, Hankey GJ. Peripheral arterial disease: prognostic significance and prevention of atherothrombotic complications. Medical Journal of Australia 2004; 181:150-154. Figure 1, p.151

Ankle-Brachial Index

Screening: 2004 ADA recommendation

“Consider” at age 50 years and every 5 years

Diagnosis:

Claudication, absent DP/PT pulses, foot ulcer

Limitations:

Underestimates severity in calcified arteries

Diabetes Care. 2005;28:2206

Diabetes Care. 2004;27(Suppl 1):S15-S35

Interpretation of the ABI

Interpretation ABI

Normal 0.90-1.30

Mild obstruction 0.70-0.89

Moderate obstruction* 0.40-0.69

Severe obstruction* <0.40

Poorly compressible** >1.30

2° to medial calcification

*Poor ulcer healing with ABI < 0.50**Further vascular evaluation needed

Risk-stratified Management of the Diabetic Foot

Low Risk

Annual comprehensive foot examination

Questionnaire completed by patient Examination

Self-management and footwear education

Brief counseling Written handout

JAMA. 2005;293:217

High Risk

Annual comprehensive foot exam

Inspect feet every office visit

Podiatry care as needed

Intensive patient education

Detect/manage barriers to foot care

Therapeutic footwear, as needed

High Risk: Nursing Tasks

Place “High-Risk Feet” stickers on each chart

Remove patient’s shoes/socks

Determine if patient can reach/see soles of feet

Stock 10-g monofilament in each room

Consider training to perform monofilament exam

Provide patient education forms

J Gen Intern Med. 2003;18:258

High Risk: Podiatry Care

Provide nail and skin care

Assess footwear needs

Visit frequency not evidence-based

Diabetes Care. 2003;26:1691

J Fam Practice. 2000;49(Suppl):S30

High Risk: Patient Education

Reinforce frequently – low retention

Patient demonstrates self-care knowledge

Evidence: May reduce foot ulcer/amputation rates

Cochrane Database Syst Rev. 2005 Jan 25;(1)CD001488

Foot Ankle Int. 2005;26:38

Basic Foot Care Concepts

Daily foot inspection

May require mirror, magnification, or caregiver

Patient able to recognize/report:

Persistent erythema Enlarging callus Pre-ulcer (callus with hemorrhage)

Basic Foot Care Concepts

Commitment to self-care

Wash/dry daily

Lubricate daily (not between toes)

Debride callus/corn (low-risk patients)

No self-cutting of nails if:

Neuropathy PAD Poor vision

Basic Foot Protective Behaviors

Avoid temperature extremes

No walking barefoot/stocking-footed

Appropriate exercise for insensate feet

Inspect shoes for foreign objects

Optimal footwear at all times

Basic Footwear Education

Avoid:

Pointed toes

Slip-ons

Open toes

High heels

Plastic

Black color

Too small

Favor:

Broad-round toes

Adjustable (laces, buckles, Velcro)

Athletic shoes, walking shoes

Leather, canvas

White/light colors

½” between longest toe and end of shoe

Diabetes Self-Management. 2005;22:33

Barriers to Foot Care

Depression

Alcoholism

Social isolation if unable to inspect feet

Financial barriers

Diab Metab Res Rev. 2004;20(Suppl 1):S13

Therapeutic Footwear Goals

Protect feet

Reduce plantar pressure, shock, and shear

Accommodate, stabilize, support deformities

Suitable for occupation, home, leisure

Diabetes Care. 2004;27:1832

Diab Metab Res Rev. 2004;20(Suppl1):S51

Therapeutic Footwear Components

Padded socks (e.g., CoolMax, Duraspun, others)

Shoe inserts/insoles (closed-cell foam, viscoelastic)

Therapeutic shoes

Therapeutic Footwear Efficacy

Decreases plantar pressure 50%-70%

Uncertain reduction in ulcer rate

Diabetes Care. 2004;27:1774

Medicare Requirements

Certify diabetic patient with foot at risk

Prescribe therapeutic footwear

Prepare/fit therapeutic footwear

Pedorthist, orthotist, prosthetist, D.P.M. www.cpeds.org

Foot Ankle Int. 2005;26:42

Medicare Coverage

Total Amount Allowed

Amount Covered by Medicare

Extra-depth shoes $132.00 $105.60

Custom-made shoes $396.00 $316.00

Diabetic pre-fab insoles $67.00 $53.60

Diabetic custom insoles $67.00 $53.60

Medicare pays 80% of payment amount allowed:

1 pair extra-depth shoes 3 pair insoles/y, or 1 pair extra-depth shoes with modification 2 pair insoles/y, or 1 pair custom-molded shoes 2 pair insoles/y

Conclusion

Diabetic foot ulcer is common

Foot ulcers have devastating consequences

Screening is simple

Screening and team care reduce diabetic foot ulcers and amputations