Monitoring Prevent. Can Temperature. DFUs

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1 Can Temperature Monitoring Prevent DFUs Alexander Reyzelman DPM Associate Professor, California School of Podiatric Medicine at Samuel Merritt University Oakland, CA Co-Director, UCSF Center for Limb Preservation UCSF San Francisco, CA

2 Disclosures Grant/Research Support: Osiris Therapeutics Mimedix Ipsen Viromed Genentech Molnycke Siren Podimetrics

3 Introduction Of the 30 million people living with diabetes in the US, 1.7 million will suffer with a DFU annually Conservative estimates of DFU-related costs in the US exceed $17 billion Re-ulceration rates for those with previous DFU have been reported between 30-40% within one year

4 Prevention In Europe, for every euro spent on ulcer prevention, ten are spent on ulcer healing. Similarly, in the research market, for every randomized clinical trial conducted on prevention, ten are conducted on healing. The strongest predictor of diabetic foot ulceration is a previous foot ulcer High recurrence rates are due to biologic and behavioral issues Bus,SA., and van Netten, JJ. (2016) A Shift in Priority in Diabetic Foot Care and Research: 75% of Foot Ulcers are Preventable. Diab Metab Res Rev, 32:

5 Prevention Prevention strategies for ulcer recurrence: Provider Patient education Routine foot care Foot surgery Patient self-management Daily self-examination Consistent use of therapeutic footwear Temperature monitoring Bus,SA., and van Netten, JJ. (2016) A Shift in Priority in Diabetic Foot Care and Research: 75% of Foot Ulcers are Preventable. Diab Metab Res Rev, 32:

6 Introduction Skin temperature monitoring emerged as a potentially useful tool in the 1970 s The majority of DFUs are preceded by repetitive micro-trauma leading to localized enzymatic autolysis of tissue and inflammation Asymmetry analysis is the practice of monitoring plantar foot temperatures in a pair of feet to identify patients with elevated risk

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8 8 Clinical Practice Guidelines Thermometry is a clinically established DFU prevention technique American College of Foot and Ankle Surgeons Diabetic patients at risk for foot lesions must be educated about risk factors and the importance of foot care, including the need for self-inspection and surveillance, monitoring foot temperatures, appropriate daily foot hygiene, use of proper footwear, good diabetes control, and prompt recognition and professional treatment of newly discovered lesions. International Working Group on the Diabetic Foot (IWGDF) Instruct a high-risk patient (IWGDF risk classification 2 or 3) to monitor foot skin temperatures at home to prevent a first or recurrent plantar foot ulcer. This aims at early recognition of inflammation followed by action taken by the patient and care provider to resolve the cause of inflammation. Wound Health Society Home monitoring of foot temperatures with an infrared thermometer reduces reulceration (Level I) By daily assessment of temperature changes, patients could identify early warning signs of tissue inflammation and reduce their activity to avert the development of an ulceration. 1. Frykberg et al. J Foot AnkleSurg. 2006;45(5 Suppl):S Bus et al. Diabetes Metab Res Rev 2016 Jan;32 Suppl 1: Lavery et al. Wound Rep Reg. 2016;

9 9 Thermometric Prevention Thermometry for the diabetic foot first emerged in the 1970s Bergtholdt. Rehab Serv Adm Bergtholdt et al. Arch Phys Med Rehab Bergtholdt HT. Phys Ther Beach RB, et al. Phys Ther Manleyet al. Arch Phys Med Rehab

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11 Thermometric Prevention Three RCTs have since examined the impact of identifying and off-loading patients with new plantar hotspots (temperatureguided avoidance therapy, TGAT) vs. standard prevention therapy on recurrence of ulceration in high risk individuals. The mean relative DFU reduction among the three RCTs was 72%. Study N Follow-up period Recurrence, Standard of Care Recurrence, TGAT Relative Reduction Lavery months 15.9% 2.4% 85% Lavery months 29.3% 8.5% 71% Armstrong months 12.2% 4.7% 61% Mean 72 % Lavery et al. Diabetes Care Lavery et al. Diabetes Care Armstrong et al. Am J Med. 2007

12 Three randomized controlled trials have shown reduction in DFU incidence by approximately 70% when using asymmetry analysis with early offloading of foot pressure The most common threshold for starting preventative therapy has been 2.22 C (4 F) over at least 2 consecutive days Despite the strong evidence, temperature monitoring remains uncommon in practice

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14 Smart Mat Prospective, multicenter cohort, non-interventional study Primary outcome endpoint: occurrence of non-traumatic plantar DFU Primary efficacy analysis: accuracy of the study device to predict DFU prior to clinical presentation Secondary outcomes: participant adherence to daily use, device-related trips and falls, and device-related injuries

15 Study Device In-home telemedicine system designed to remotely monitor and analyze temperature asymmetry Daily use wireless mat with 2000 temperature sensors under a water resistant mat Step on the mat for 20 seconds The device records a temperature scan (thermogram) of the feet Mat notifies the patient that scan is complete and transmits data securely and in compliance with HIPAA to the manufacturer Data are saved, processed, and analyzed for asymmetry

16 Inclusion Criteria Type 1 or Type 2 DM Age > 18 History of healed prior plantar DFU Exclusion Criteria ABI <0.5 History of major amputation Open plantar wound Active Charcot ESRD Active malignancy Immunosuppressive disease Cognitive deficit

17 Analysis Plan and Statistics Two sub-cohorts: Those that developed at least one DFU Those who remained ulcer free Definitions: True-positive cases in which a given temperature asymmetry threshold was exceeded in any 2 consecutive scans prior to the participant developing a DFU False-positive cases in which the threshold was exceeded but the participant did not develop a DFU

18 Results 7 sites 129 patients 37 patients (28.7%) presented with 53 ulcerations during the study At 2.22 C, the system correctly identified 97% of observed DFU Average lead time 37 days False Positive Rate 57%

19 Participant Disposition and Adherence 129 participants 14 (10.9%) withdrew consent 3 (2.3%) died 24 (18.6%) lost to follow-up 86% of the cohort used the system 3 days/week or more Mean adherence was 5.0 days/week 98.4% of participants were able to set up and use the device at home without assistance 88 % of participants reported easy ease of use No device-related adverse events reported

20 Results Case Examples 61-year-old male History L Hallux DFU Healed 40 weeks History R Hallux Amp Healed 42 weeks At no time during the study did he exceed asymmetry temperature thresholds 59-year-old female History DFU R hallux and R 5 th met head No surgery Healed 11 weeks Temperature asymmetry exceeded multiple times DFU 5 th met head recurred at week 10

21 Conclusions Plantar temperature asymmetry is highly predictive of impending DFU Using 2.22 C asymmetry, the mat was able to detect 97% of non-traumatic DFU 5 weeks before presenting to the participant or clinician Supports incorporation of daily thermometry into standard preventative care Daily adherence was encouraging with 86% of the cohort averaging at least 3 uses per week

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24 Summary We need to focus more on prevention Temperature monitoring is currently the only objective measure of tissue injury There s evidence to support that temperature monitoring does in-fact predict foot ulcer development in diabetic patients.

25 Can Temperature Monitoring Prevent DFUs Alexander Reyzelman DPM Associate Professor, California School of Podiatric Medicine at Samuel Merritt University Oakland, CA Co-Director, UCSF Center for Limb Preservation UCSF San Francisco, CA