The Underestimation of PAD & Its Impact on Wound Care

The number of people in the United States in 2014 diagnosed with diabetes is a staggering 29.1 million (9.3% of the population).¹ Within this cohort, one in three patients older than 50 also has been diagnosed with peripheral arterial disease (PAD).² However, frequently published prevalence statistics of 8-12 million people who are said to be living with PAD in the US and the paucity of publications dealing with diabetic PAD seem to undercut the severity of the climbing rate of PAD, particularly among wound care patients.”³ If wound care providers are to play a role in improving awareness of PAD, as well as to improve on making earlier diagnosis and more appropriate care plans, the literature related to the presence of PAD needs to be more accurate. Over the past 10 years, the SAGE Group (Atlanta) has advocated for a re-examination of these analyses. Cited thousands of times in popular and professional publications, the original citation of PAD prevalence appears to date to the 1980s and is based upon “subjects … from a predominantly white, upper-middle-class community in southern California.”⁴ The SAGE Group research asserts that the true prevalence of PAD can be better determined by the “Diabetes Method,” which relies on using diabetes as a causative factor in vascular disease. Using this approach, SAGE Group found a PAD prevalence of 17.6 million people in the US. This agrees with statistics regarding metabolic syndrome, which now affects 34-39% of the adult population.⁵ Metabolic syndrome is a risk-factor cluster that includes abdominal obesity, hypertension, dyslipidemia, and insulin resistance.⁶ Metabolic syndrome sets the stage for development of diabetes as well as coronary and peripheral vascular occlusive disease: cerebrovascular (CVD), cardiovascular (CAD), renal artery disease, and PAD. The in-common behavioral risks for these disease manifestations are smoking, poor diet, and lack of exercise. Since PAD is often the first warning sign that a patient has a chronic disease within the circulatory system,⁷ it remains critical that wound care providers engage in practices focused on early recognition of PAD in patients living with metabolic syndrome and/or diabetes in order to administer appropriate care and improve health outcomes. Consider the larger health implications: 60% of PAD patients also live with CAD and 25% of PAD patients also live with CVD.⁸ Therefore, the two most significant drivers of PAD – advancing age and diabetes – should escalate concern with respect to identifying and treating PAD early and effectively.

Diabetic Neuroischemic Disease
In 2010, the SAGE Group published its analysis of diabetes and PAD as well as the impact of PAD on diabetic foot ulcer (DFU) incidence and resulting amputation. It was found that diabetes increased the risk of developing foot ulcers by 15-25%. Applying this to the 2010 population, researchers arrived at an annual incidence of approximately 1 million new DFUs and a 28-fold increased risk of amputation.³ The report underscored that prevalence of diabetes and DFU is coincident with age, meaning the majority of affected patients are concentrated in those aged 65 and older — a rapidly growing population sector. While age is a factor in the progression of diabetes morbidity, the most important factors in developing DFUs are neuropathy and ischemia.⁹ DFUs are categorized as neuropathic, ischemic, and combination disease (ie, neuroischemic). The SAGE Group estimates the current prevalence of each is 35%, 15%, and 50%, respectively, which translates to a staggering 2.5 million patient prevalence and 600,000 patient incidence.³ Using comorbid cardiac disease and diabetes as a method to identify PAD, other publications corroborate that PAD is highly prevalent in patients living with diabetes, but frequently underdiagnosed and undertreated.^10,11

In 2006, Lavery et al published one of the first studies to definitively document PAD as an independent risk factor for infection in patients living with diabetes, resulting in a two-fold increase in occurrence.¹² Fast forward to 2010, and the SAGE Group study that found the total prevalence of ischemic and neuroischemic DFU complicated by infection in the US is 1.58 million patients and the incidence is 378,000 patients.³

Diabetic neuroischemic ulcers are recognized as requiring special care since this patient population is at the highest risk of amputation and death.¹³ Importantly, newly formed (< 1 month duration) neuroischemic DFUs are associated with severe adverse outcomes, including lower primary healing, higher probability of ulcer recurrence, greater risk of minor and major amputations, and higher mortality (see figures 1 and 2).¹⁴

The cost of care of Medicare beneficiaries with a DFU is about $33,000 per year since they are seen by their outpatient healthcare provider about 14 times annually and are hospitalized about 1.5 times each year. Beneficiaries with a lower extremity amputation are seen by their provider about 12 times per year and hospitalized about twice per year. The cost of care for these beneficiaries is $52,000 for total reimbursement of all Medicare services per year.¹⁵ Rice et al published “excess healthcare costs of DFU are approximately twice that attributable to treatment of diabetes itself, and the presence of DFU approximately triples the excess cost differential versus a population of patients without diabetes.” They went on to say their estimates understated the actual burden of DFU because the incremental costs they used did not consider other factors such as prescription drug costs, costs borne by supplemental insurers, or informal caregiving, to name a few.¹⁶

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We Find What We Look For
Patients living with diabetes, known as the “multi-opathy” disease (ie, retinopathy, nephropathy, vasculopathy, and neuropathy), may develop conditions requiring the services of various specialty providers over the long term. Advanced disease may produce a certain white-coat fatigue, making it difficult to remember to ask questions, much less remember clinician directions from appointment to appointment. Indeed, nearly half of all US adults have trouble understanding what a doctor tells them, according to the Institute of Medicine.¹⁷ Added to this, we know 50% of people living with PAD have no symptoms and that a majority of patients undergoing amputation do not receive angiogram.^18,19 Indeed, the true prevalence of PAD in patients living with diabetes or with diabetes and kidney disease has been difficult to determine secondary to insensitivity in diagnostic means and underappreciation of the role that calcium plays in occlusive disease below the knee and ankle.^20,21

Even more startling is the delay in implementation of arterial assessment as a Physician Quality Reporting System (PQRS) measure for patients living with DFUs. In 2008, the US Wound Registry (USWR) launched its “Do The Right Thing” initiative, which recommends arterial screening of all patients living with chronic, nonhealing ulcers. The measure was tested in six wound care hospital-based outpatient departments (HOPDs) and demonstrated that a related quality measure can significantly increase arterial screening by physicians, according to USWR officials. However, the Centers for Medicare & Medicaid Services (CMS) twice rejected a vascular-screening measure for inclusion in the PQRS in 2009 and 2011. It was not until the advent of the Qualified Clinical Data Registry option for PQRS reporting in 2015 that the USWR was able to get CMS approval for a vascular-screening measure. At this time, the measure can only be reported through the USWR. However, it can be reported from any electronic health record (EHR) certified for stage II of Meaningful Use by downloading the appropriate electronic clinical quality measure files (for more, visit www.uswoundregistry.com/specifications.aspx) and asking one’s EHR vendor to install them into the EHR.²² Once a DFU happens, rapid assessment and triage is required. With the realization that these ulcers are likely neuroischemic, it makes sense to prioritize objective and rapid vascular, infection, and pressure assessment on all patients.²³ USWR lists evaluation measurements: ankle-brachial index (ABI), skin perfusion pressure (SPP), transcutaneous oximetry (TcPO₂), and Doppler vascular studies. Sadly, USWR data indicates fewer than 10% of patients living with chronic, nonhealing leg ulcers undergo any type of vascular assessment (ABI, SPP, or TcPO₂), even at HOPDs.²⁴ In 2014, the Society for Vascular Surgery added its voice to promote a new risk stratification framework for neuroischemic disease and termed it “WIfI” for the three major factors impacting amputation risk and patient management: namely wound, ischemia, and foot infection.²⁵

The need for a paradigm shift has never been more pressing. Adherence to protocols using SPP assessment,²⁶  aggressive infection management,²⁷ and total contact cast offloading²⁸ are proven to promote limb preservation and dramatically reduce amputations.

Treatment Options for Neuroischemic DFUs
Multidisciplinary care teams focused on amputation prevention²⁹ in this patient population face a hurdle seen in diagnosis – particularly, calcification secondary to diabetes and renal disease.³⁰ This has been a focus of endovascular product development in the form of atherectomy (directional, orbital, or rotational),^31,32  drug-coated balloons,³³ and drug-eluting stents.³⁴

Angiosome-directed diagnosis coupled with wound-angiosome revascularization demonstrates limb salvage in the patient living with chronic limb ischemia (CLI) is remarkably safe and effective. A recently published systematic review and meta-analysis of 23 studies including one randomized controlled trial showed no difference in clinical outcomes for patients living with CLI treated with endovascular or surgical revascularization. Comparison parameters included overall death, amputation, and amputation-free survival > 2 years.³⁵ According to Rutherford Classification stage VI, DFU patients can be assessed prior to endovascular procedure to determine the likelihood of ulcer healing using predictive SPP of target wound angiosome(s) prior to direct vessel revascularization of the wound angiosome(s).³⁶ Significantly, SPP appears to be the better predictor of wound healing, freedom from major adverse limb experience, and amputation-free survival compared to ABI when assessing patient outcomes one year after endovascular therapy. It was postulated that this was secondary to the role that calcium plays in obscuring ischemic disease when using ABI alone.³⁷

Conclusion
Multidisciplinary teams are the new “normal” for improving outcomes for chronic disease conditions.³⁸ Limb-preservation protocols are increasingly promoted; two of note are included in Figure 3³⁹ and Figure 4.⁴⁰ All patients living with diabetes merit periodic vascular assessment to prevent ulceration and all patients who develop lower extremity ulcers must undergo vascular testing to prevent amputation.

Audrey Moyer-Harris is a long-time nurse and owner of LEAP Synergies Inc., a nonprofit organization that provides PAD awareness programs for healthcare professionals and patients and contracting services to healthcare facilities seeking to create limb-preservation centers of excellence. An active member of the Association for the Advancement of Wound Care and the Wound, Ostomy and Continence Nurses Society^TM (WOCN), she received Industry Nurse of the Year recognition from the St. Louis branch of the WOCN in 2014 and is an advocate for proper vascular assessment of all lower extremity ulcers. She has no financial disclosures.

References

1.
Centers for Disease Control and Prevention. 2014 National Diabetes Statistics Report. Accessed online: www.cdc.gov/diabetes/data/statistics/2014StatisticsReport.html.

2.
American Diabetes Association. Living with Diabetes, Heart Disease/Peripheral Arterial Disease. Accessed online: www.diabetes.org/living-with-diabetes/complications/heart-disease/peripheral-arterial-disease.html. 

3.
Yost ML. Diabetic Foot Ulcers, peripheral arterial disease and critical limb ischemia. The SAGE Group. 2010.

4.
Criqui MH, Fronek A, Barrett-Connor E, Lauber MR et al. The prevalence of peripheral arterial disease in a defined population. Circulation. 1985;71:510-515.

5.
Ford ES. Prevalence of the metabolic syndrome defined by the International Diabetes federation among adults in the U.S. Diabetes Care. 2005;28:2745-2749.

6.
National Heart, Lung and Blood Institute. Risk Factor Clustering and the Metabolic Syndrome. Accessed online: www.nhlbi.nih.gov/health-pro/guidelines/current/cardiovascular-health-pediatric-guidelines/full-report-chapter-12.

7.
Why PAD Matters. American Heart Association. Accessed online:www.heart.org/HEARTORG/Conditions/More/PeripheralArteryDisease/Why-PAD-Matters_UCM_301303_Article.jsp.

8.
Golomb BA, Dang TT, Criqui MH. Peripheral arterial disease morbidity and mortality implications. Circulation. 2006;114(7):688-699.

9.
Clayton W, Elasy TA. A review of the pathophysiology, classification and treatment of foot ulcers in diabetic patients. Clinical Diabetes. 2009; 27(2):52-58.

10.
Lange S, Diehm C, Darius H, Haberi R, et al. High prevalence of peripheral arterial disease but low antiplatelet treatment rates in elderly primary care patients with diabetes. Diabetes Care. 2003; 26(12):3357-8.

11.
Norman PE, Davis WA, Bruce DG, Davis TM. PAD and risk of cardiac death in type 2 diabetes: The Fremantle diabetes study. Diabetes Care. 2006;29:575-80.

12.
Lavery LA, Armstrong DG, Wunderlich RP, Mohler MJ et al. Risk factors for foot infections in individuals with diabetes. Diabetes Care. 2006; 29:1288–1293.

13.
Ndip A and Jude EB. Emerging evidence for neuroischemic foot ulcers: Model of care and how to adapt practice. Int J Low Extrem Wounds. 2009;8(2):82-94.

14.
Moulik PK, Mtonga R, Gill GV. Amputation and mortality in new-onset diabetic foot ulcers stratified by etiology. Diabetes Care. 2003;26(2):491–4.

15.
Margolis DJ, Malay S, Hoffstad OJ, Leonard CD et al. Economic burden of diabetic foot ulcers and amputations. Agency for Healthcare Research and Quality. January 2011. 10(11)-EHC009-2-EF.

16.
Rice JB, Desai U, Cumming AKG, Birnbaum HG, et al. Burden of diabetic foot ulcers for medicare and private insurers. Diabetes Care. 2014; 37:651-658.

17.
Nielsen-Bohlman L, Panzer AM, Kindig DA, eds. Health Literacy: A prescription to end the confusion. The National Academies Press. 2004. Accessed online: www.nap.edu/catalog.php?record_id=10883

18.
Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic). J Am Coll Cardiol. 2006;47(6):1239-1312.

19.
Goodney PP, Travis LL, Nallamothu BK et al. Variation in the use of lower extremity vascular procedure for CLI. Circ Cardiovasc Qual Outcomes. 2012;5:94-102.

20.
Padberg FT, Back TL, Thompson PN, Hobson RW. Transcutaneous oxygen estimates probability of healing in the ischemic extremity. J Surg Res. 1996; 60(2):365-369.

21.
Elhadd TA, Robb R, Jung RT, Stonebridge PA, Belch JJF: Pilot study of prevalence of asymptomatic peripheral arterial occlusive disease in patients with diabetes attending a hospital clinic. Pract Diabetes Int. 1999;16:163-166.

22.
Quality Measures in Wound Care. US Wound Registry. 2014. Accessed online: www.uswoundregistry.com/Specifications.aspx

23.
Snyder RJ, Frykberg RG, Rogers LC, Applewhite AJ et al. The management of diabetic foot ulcers through optimal off-loading. J Am Pod Med Assoc. 2014;104 (6):555-567.

24.
Nielsen-Bohlman L, Panzer AM, Kindig DA, eds. Health literacy: A prescription to end the confusion. The National Academies Press. 2004. Accessed online: www.nap.edu/catalog.php?record_id=10883

25.
Mills JL Sr, Conte MS, Armstrong DG, et al. The society for vascular surgery lower extremity threatened limb classification system based on wound, ischemia, and foot infection (WIfI). J Vasc Surg. 2014;59:220-34.e1-2.

26.
Talarico R. Preventing diabetic foot amputations: Podiatry, protocols and perfusion. J Diabetic Foot Complications. 2014;6(1)3:19-23.

27.
Driver VR, Madsen J, Goodman RA. Reducing amputation rates in patients with diabetes at a military medical center. The limb preservation service model. Diabetes Care. 28:248–253.

28.
Quality Measures in Wound Care. US Wound Registry. 2014. Accessed online: www.uswoundregistry.com/Specifications.aspx

29.
Rogers LC, Andros G, Caporusso J, et al. Toe and flow: Essential components and structure of the amputation prevention team. J Vasc Surg. 2010;52:23S-27S.

30.
Bishop PD, Feiten LE, Ouriel K, Nassoiy SP et al. Arterial calcification increases in distal arteries in patients with peripheral arterial disease. Ann Vasc Surg. 2008;22(6):799-805.

31.
Cioppa A, Stabile E, Popusoi G, et al. Combined treatment of heavy calcified femoropopliteal lesions using directional atherectomy and a paclitaxel coated balloon: One-year single centre clinical results. Cardiovasc Revasc Med. 2012;13(4):219-223.

32.
Mustapha JA and Diaz-Sandoval LJ. Arterial deposition of calcium and outcomes of peripheral interventions: is it time to redefine the “gold standard?” Vasc Disease Management. 2013;10(10):E208-E211

33.
Tepe G, Laird J, Schneider P, et al. Drug-coated balloon versus standard percutaneous transluminal angioplasty for the treatment of superficial femoral and popliteal peripheral artery disease: 12-month results from the IN.PACT SFA randomized trial. Circulation. 2015;131(5):495-502.

34.
Ansel G. Zilver PTX randomized trial of Paclitaxel-eluting stents for femoropopliteal artery disease: 4-year results. Presented at VIVA 2013; Las Vegas.

35.
Jones WS, Dolor RJ, Hasselblad V, et al. Comparative effectiveness of endovascular and surgical revascularization for patients with peripheral artery disease and critical limb ischemia: Systematic review of revascularization in critical limb ischemia. Am Heart J. 2014;167(4):489-498.e7.

36.
Utsunomiya M, Nakamura M, Nagashima Y, Sugi K. Predictive value of skin perfusion pressure after endovascular therapy for wound healing in critical limb ischemia. J Endovasc Ther. 2014;21:662–670.

37.
Okamoto S, Iida O, Nakamura M, Yamauchi Y, et al, on behalf of the OLIVE Investigators. Postprocedural skin perfusion pressure correlates with clinical outcomes 1 year after endovascular therapy for patients with critical limb ischemia. Angiology 2015; doi 10:1177/0003319715569907.

38.
Hanna A. Ontario Medical Association Policy on Chronic Disease Management. Ontario Medical Association. Ontario, Canada. 2009.

39.
Mills JL Sr, Conte MS, Armstrong DG, et al. The society for vascular surgery lower extremity threatened limb classification system based on wound, ischemia, and foot infection (WIfI). J Vasc Surg. 2014;59:220-34.e1-2.

40.
Diaz-Sandoval LJ, Mustapha J, Saab F, Vantil B. The CLI continuum of care model: A multidisciplinary approach to improve outcomes. CLI Compendium. 2014;1(5).