The Diabetic Foot. Tim Greenaway PhD, FRACP Department of Endocrinology Royal Hobart Hospital

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1 The Diabetic Foot Tim Greenaway PhD, FRACP Department of Endocrinology Royal Hobart Hospital

2 Diabetes Prevalence Projected to Reach 366 Million by 2030 About 171 million adults worldwide diagnosed with diabetes in % world s population Between 2000 and 2030, the prevalence of diabetes in adults will double because of population ageing and urbanisation EUROPE ASIA USA 2000: 30.8M 2000: 71.8M 2000: 15M 2030: 41M 2030: 180M 2030: 30M AMERICAS (Ex-US) 2000: 20M AFRICA JAPAN 2000: 6.9M 2030: 8.9M MIDDLE EAST OCEANIA 2030: 18.7M 2000: 20M 2000: 0.8M 2000: 7.1M 2030: 33M Adapted from Wild S et al Diabetes Care 2004;27: : 52.8M 2030: 1.5M

3 Health Care Costs Associated with Diabetes US CDC 2003 $13,243US for each person with diabetes Direct medical costs $91.8 billion US per annum Economic burden of diabetes related to complications

4 Health Costs Australian Health Care Costs for Patients with Type 2 Diabetes (DiabCost 2002) Overall Complications None Micro- Macro- Both Direct $5325 $3990 $6990 $8985 $9610 Indirect $35 $35 $35 $70 $35 TOTAL $5360 $4025 $7025 $9055 $9645 Subsidies $5540 $5075 $6200 $6120 $6240

5 Diabetes-Related Foot Complications Leading cause of admission to hospital in diabetic patients (under-reported reported Wraight et al. 2006) - 25% of Australian Teaching Hospital inpatients have diabetes - of these, 20% have foot pathology requiring acute care

6 Diabetes-Related Foot Complications Foot ulceration most common foot complication (Boulton et al. 2004) Diabetes is the major cause of non-traumatic lower-limb limb amputations (Pecoraro et al. 1990) >2600 diabetes-related lower limb amputations annually in Australia (Payne 2000) per 100,000 total population

7 Diabetes-Related Foot Ulcers 15% diabetic patients will develop foot ulcers (Reiber 1998) Annual incidence 2% (5-7.5% in patients with peripheral neuropathy) (Boulton et al. 2004) Foot ulcers reported by 12.4% Tasmanian insulin-treated diabetic patients (Sale et al. 2002) A person who has had an ulcer is at life-long long risk of further ulceration

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11 Seattle Diabetic Foot Study (Boyko( et al. Diabetes Care 2006) 1,285 patients Mean age at baseline 62.4 years Mean follow up 3.38 years 7 clinical factors independently associated with ulcer occurrence (Cox proportional hazards modelling): HbA1C, impaired vision, prior foot ulcer, prior amputation, monofilament insensitivity, onychomycosis ( OR);( tinea pedis ( OR)(

12 Relative risk HbA 1 C and Relative Risk of Microvascular Complications A1c (%) Retinopathy Nephropathy Neuropathy Microalbuminuria DCCT, Diabetes Control and Complications Trial. 1. Adapted from Skyler JS. Endocrinol Metab Clin North Am 1996;25: DCCT. N Engl J Med 1993;329: DCCT. Diabetes 1995;44:

13 Relative Risk of Progression of Diabetic Complications DCCT 1,2 Kumamoto 3 UKPDS 4 HbA 1c 9% to 7% 9% to 7% 8% to 7% Retinopathy 63% 69% 17 21% Nephropathy 54% 70% 24 33% Neuropathy 60% Macrovascular Disease 41%* 16%* *Not statistically significant in intervention analysis. 1 DCCT Research Group. N Engl J Med. 1993;329: DCCT Research Group. Diabetes. 1995;44: Ohkubo Y, et al. Diabetes Res Clin Pract. 1995;28: UK Prospective Diabetes Study Group (UKPDS) 33: Lancet. 1998;352:

14 Diabetic Distal Symmetrical Polyneuropathy Length dependent sensory and motor neuropathy Prevalence 30% (12.3% at diagnosis) Metabolic and vascular factors important in pathogenesis (Cameron et al. 2001) Most important sequela foot ulceration

15 Pathophysiology of Diabetic Neuropathy

16 Evaluation of Peripheral Nerve Function Semmes-Weinstein monofilament (4 sites) 128 C tuning fork Biothesiometry (Boulton et al. 1986) VPT > 25 10x more likely to ulcerate VPT > 43 30x more likely to ulcerate NCS

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18 Evaluation of Peripheral Vascular Status (1) Symptoms: claudication, rest pain Signs: femoral bruits absent pedal pulses T, pallor on foot elevation/dependent rubor, capillary filling time >5s, hair loss

19 Evaluation of Peripheral Vascular Investigations: Status (2) ABI Duplex US Angiography

20 Lower Limb Arterial Doppler Tracings Normal Diabetic

21 Angiographic Findings in Diabetic PVD

22 Evaluation & Treatment of Diabetic Foot Ulcers (Kruse et al. 2006) Assessment for foot deformity Assessment of neurological and vascular status Debridement Dressings Offloading Infection control (assess for osteomyelitis)

23 Antibiotic Therapy in Diabetic Foot Ulcers (Boulton et al. 2004) Little data Infection should assessed clinically ± deep wound/tissue cultures Serious infections are polymicrobial and may include anaerobes Common pathogens include s. aureus (±MRSA), β-haemolytic streptococci, enterobacteriaceae,, pseudomonas aeruginosa and enterococci

24 Duration of Antibiotic Therapy in Diabetic Foot Ulcers Soft-tissue tissue infections: 1-22 weeks Osteomyelitis: 6 weeks

25 Clinical Indicators of Osteomyelitis Large or penetrating ulcer Recurrent or refractory ulcer Bone that can be seen or probed

26 Probe to Bone

27 Charcot s s Arthropathy vs Osteomyelitis Clinical assessment (joint deformity, pain/tenderness, swelling, bounding pulses, erythema, warmth) ESR/Alkaline phosphatase X-ray/MRI tarsal-metatarsal and tarsal joints (Charcot s) cf 1 st /5 th MTP joints, 1 st distal phalanx, calcaneus, association with ulcer (osteomyelitis)

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29 Lined Bivalved Fibreglass Cast

30 The Diabetic Foot Areas of Uncertainty Prevention: Education Screening Specialised footwear Therapy: Dressings Hyperbaric oxygen Platelet-derived growth factor Tissue-engineered engineered skin

31 Diabetes-Related Foot Complications The Australian National Diabetes Strategy and Implementation Plan (1998) called for a 50% reduction in lower-limb limb amputation by 2005 and an 80% level of screening for diabetic foot disease risk factors each year

32 However Only 41% Tasmanian insulin-treated diabetic patients are currently screened for diabetic foot disease risk factors each year (Sale et al. 2002)

33 Frequency of Foot Examination in Patients with Diabetes (ADS 2000) Impact of frequency of foot examination on clinical outcomes not defined Minimum frequency of foot examination once a year People with at risk feet should receive routine podiatry care People with a foot ulcer should be cared for by a multidisciplinary footcare team

34 Multidisciplinary Foot Clinics Multidisciplinary footcare teams (podiatrist, physician, specialist nurses, orthotist, vascular surgeon) improve rates of ulcer healing and reduce the rates of recurrence and amputation in diabetic patients with high risk feet (Larsson et al. 1995, Dargis et al. 1999, Wraight et al. 2006)