ABSTRACT: Our aim was to determine awareness of peripheral artery disease (PAD) treatment options and referral of patients at high risk of PAD to specialty care via a cross-sectional online survey of 500 clinicians (nephrologists, endocrinologists, and internists) from across the US. The questionnaire was developed to collect details on basic demographics, risk factors, and vascular disease characteristics of the surveyed clinicians’ patient population. In addition, PAD awareness, diagnostic testing, and referral likelihood relative to atherosclerotic risk factors and disease conditions were assessed. Seventy-five percent of the clinicians use at least one test to diagnose PAD and 63% to treat PAD instead of referring to a specialist. In addition, 74% utilize a ‘watchful waiting’ approach with PAD patients. Sixty-three percent of respondents do not consider chronic, non-healing wounds as a reason to refer the patient to a specialist. When deemed necessary, 86% refer patients with PAD to other specialists with the majority (97%) referring to vascular surgeons. Only 0.6% of referrals to a PAD specialist are initiated by the patients themselves. Lastly, 95% of responding clinicians believe appropriate diagnosis and intervention can usually prevent atraumatic primary amputation. Further studies/surveys should be completed to confirm the implications for improved PAD awareness and the need for expedited referrals of high-risk patients.

VASCULAR DISEASE MANAGEMENT 2017;14(6):E137-E142.
Key words: peripheral artery disease, disease awareness, diabetes, end-stage renal disease, 
treatment options, referral

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Peripheral artery disease (PAD) is a highly prevalent atherosclerotic syndrome that affects approximately 18 million people in the US.¹ Approximately half of the patients with PAD are asymptomatic, with typical symptoms present in only 20%.^2,3 The prevalence of PAD increases with advancing age, as approximately 20% of people older than 70 years have the disease.⁴ The risk of PAD is also strongly associated with smoking and a history of other forms of atherosclerotic disease.⁵ 

Critical limb ischemia (CLI) is the most severe form of PAD and the majority of the CLI patients suffer from diabetes and end-stage renal disease (ESRD).⁶ Sixty to 80% of CLI patients have diabetes^7,8 and 15%-20% of ESRD patients have CLI.^9,10 During the first year of CLI diagnosis, 40% to 60% of patients with diabetes will experience an amputation while 20% to 25% among them will die.^8,11,12 Studies have shown that among persons with diabetes-related amputations, 9-20% may experience a second amputation within 12 months, and 28-51% within 5 years of the first one.¹¹

Diabetic foot complications are the most common cause of non-traumatic lower extremity amputations. It is estimated that 15% of patients with diabetes will develop a foot ulcer during their lifetime and approximately 14%–24% of those with a foot ulcer will require an amputation.¹³ Moreover, in diabetic patients with CLI, renal insufficiency increases risk of non-healing wounds and major amputation.⁶ Primary amputation rates of 22% to 44% have been reported for ischemic foot lesion in ESRD patients.¹³

The high rate of amputation in this patient population could be the result of late referrals to specialists.^14-16 Few studies have reported on patterns of referral in diabetic foot disease. MacFarlane and Jeffcoate found that the median time between onset of the foot ulcer and referral to a specialist clinic was 19 days.¹⁷ In the Eurodiale Study, 27% of the patients with diabetic foot ulcer had been treated for more than 3 months by primary care physicians and general practitioners before referral to the foot clinic.¹⁸ 

Factors that impede early referral may include lack of physician awareness of PAD and more specifically, the underestimation of the severity of foot infection and lack of recognition of ischemia due to PAD.^15,19 The underdiagnosis of PAD in primary care practice was first described in the PARTNERS trial,²⁰ a cross-sectional study conducted at 27 sites in 25 cities and 350 primary care practices throughout the US. They found that 83% of the patients with a previous diagnosis of PAD were aware of the diagnosis, but only 49% of their physicians had recognized the PAD diagnosis at the time of screening. Research shows that only 25% of patients with PAD are undergoing treatment,²¹ and the atherosclerosis risk factor control is less frequent in these patients as compared to those with coronary artery disease.²²

Preliminary survey (Direct face-to-face)

A small PAD awareness and referral habits survey of 50 primary care physicians and nephrologists was carried out in 2014.²⁷ Sixty percent of respondents were nephrologists; the majority managed a significant number of patients who were positive for tobacco, diabetes, and kidney disease. Only 42% percent of respondents were aware of certain risk factors for PAD. Sixty percent of respondents did not refer patients with lower extremity wounds to PAD specialists; 85% of respondents did not perform vascular assessment in their clinic; and, 72% of respondents did not refer patients with diabetes to specialists for vascular assessment or for diabetes management. The primary care physicians and nephrologists surveyed in this study demonstrated that there is a general lack of awareness of PAD and its varied clinical presentations. Based on these results, we decided to set up an online survey to reach a much broader physician population across the US.

Objectives

The purpose of this study was to build upon our previous findings and:

• To characterize clinicians’ patient populations.
• To assess the awareness of PAD and current diagnosis tools, as well as referral patterns amongst the clinicians.
• To identify decision-making criteria for when patients are referred, to which specialty, and why.

Methods

This cross-sectional online survey of five hundred (500) clinicians (nephrologists, endocrinologists, and internists) from across the US was conducted in 2014. The survey was designed to assess PAD, diabetes, and ESRD census and management (screening, testing, and referral) in the primary care, nephrology, and endocrinology medical communities. The survey instrument measured demographics, risk factors, and vascular disease characteristics of the surveyed clinicians’ patient population and then assessed PAD awareness, testing, and referral likelihood relative to atherosclerotic risk factors and disease conditions. 

The survey had 19 yes/no or multiple-choice questions and 1 open-ended question. See Appendix A for the full survey. The survey was conducted by Reckner Healthcare (Chalfont, PA), took less than 10 minutes to complete and respondents were provided a $50 honorarium. 

Data were then entered into SAS software and analyzed using descriptive statistics. Data were reported as percentage. Differences in responses between selected clinician groups were analyzed using the chi-squared test with the statistical significance was set at P≤.05.

Results

Characteristics of respondents. Twenty percent of the 500 respondents were internists, 36% endocrinologists and 44% nephrologists. Forty-one percent of the respondents were from 4 states: 18% from California, 11.6% from New York, 6.8% from New Jersey and 5% from Illinois as shown in Figure 1.

Patient population. The responding clinicians indicated that they see 343 patients per month on average—internists see significantly more patients than nephrologists and endocrinologists (434 vs. 315 and 327, respectively; P<.05). Forty-nine percent of their patients are 65 years of age or older, 55% have either diabetes or CKD/ESRD, 32% have a history of smoking, and 15.5% have prior lower extremity amputation. Nephrologists see significantly more patients that are 65 years or older, African-American, renal insufficient (CKD/ESRD), or with a history of stroke or heart attack. Endocrinologists, however, treat significantly more patients that are diabetic, obese, or hyperlipidemic. In this survey, the physicians indicated that 32.5% of the diabetic patients and 43.2% of the CKD/ESRD patients have PAD; however, only 59% of the clinicians talk to their patients about their risk for PAD.

PAD awareness. Most of the clinicians have a solid understanding of PAD, 67% learned about PAD via Continuing Medical Education (CME) and 60% rely on previous medical school and/or residency learning. About 90% of the clinicians are aware that PAD can be treated with exercise (92%), medication (95%), bypass (93%), angioplasty (93%) and stents (91%), but only 65% of them know about atherectomy, and 72% think that amputation is one of the therapeutic interventions for treating PAD (Table 1).

Clinical approach for PAD. Diagnosis. Thirty-two percent of the endocrinologists do not use a test to diagnose PAD, significantly more than the 21% of nephrologists and 6% of internists (P<.05). However, 78% of the clinicians use at least one test to diagnose PAD. The majority of physicians use medical examination (70%), ABI (87%), duplex ultrasound (73%), or a perfusion test (11%) for patient assessment and diagnosis. Significantly more endocrinologists use medical exams to diagnose PAD (78.5%) than nephrologists (66.5%) or internists (66.7%). Also, significantly more nephrologists use TBI (12.1%) than endocrinologist (11.6%) or internists (7.5%), and more internists use ABI (93.5%) than nephrologists (80.3%) or endocrinologists (90.1%).

Treatment options. On average, 63% of the clinicians treat PAD, however, 92% of internists treat PAD compared to only 58% of the nephrologists and 54% of the endocrinologists (P<.05). In addition, 74% of the clinicians utilize a ‘watchful waiting’ approach with PAD patients, opting for a monitoring treatment method (Table 2). More than 93% of clinicians treat with medications and smoking cessation.

Clinician respondents (86%) also refer patients to other specialists, and of those, 97% refer their patients to vascular surgeons. They refer patients to specialists if the wound does not heal (87%), patient presents with numerous risk factors (44%), or patient complains of leg pain (74%). There are 61% of the clinicians that do not refer patients to PAD specialists because managing other comorbidities is a priority for them. Interestingly, 49.5% of the internists do not refer patients with PAD because they prefer to treat the patients themselves, compared to 17.4% of nephrologists and 21.2% of endocrinologists (P<.05). Other reasons include poor experience with interventions (18%), not aware that patient has PAD (29%) or insurance problems (25%). Also, 40% to 70% of the clinicians treat lower extremity wounds (Figure 2); however, 97% of the clinicians refer rather than treat patients with non-healing wounds (37%) or if they do not have enough experience (31%). Less than 1% of referrals from responding clinicians are initiated by the patients themselves (Table 3). 

Discussion

Previous studies have documented that PAD is often underdiagnosed and undertreated.^20,23,26 This survey was designed to increase our understanding of the awareness of PAD treatment options among clinicians and provide information on current screening, diagnostic, and referral practices. The current findings recapitulate the findings of a smaller 50 clinician survey and reiterate the importance of increased education regarding minimally invasive endovascular options to treat PAD compared to surgical options. It is surprising that 95% of responding clinicians still believe appropriate diagnosis and intervention can usually prevent amputation, even though high levels of amputations are still seen in the US.²⁴ Interestingly, 78% of responding clinicians use at least one test to diagnose PAD; these tests include medical examination, Doppler ultrasound, tissue perfusion, and ABI/TBI. These tests, however, are historically unreliable in patients with advanced PAD or CLI.²⁵ In addition, 74% of responding clinicians utilize a ‘watchful waiting’ approach with PAD patients, opting for a monitoring treatment method and 63% do not consider chronic, non-healing wounds as a reason to refer the patient to a specialist. However, when deemed necessary, 86% routinely refer patients with PAD to other specialists with the majority (97%) referring to vascular surgeons. The patients themselves also take a ‘wait and see’ attitude – as only 0.6% of referrals from responding clinicians are initiated by the patients themselves. The results of this survey may indicate an unfortunate path to amputation (Figure 3) that some of these patients find themselves in. This may be due to a lack of PAD awareness among patients and physicians, leading to delayed diagnosis and proper treatment. Or they view other comorbid conditions as a priority further delaying the treatment of PAD until non-healing wounds are present. Even at that point, patients rarely advocate for themselves, delaying referral to a PAD/CLI specialist. Once the condition has escalated to CLI there is an increased likelihood of higher costs to treat the disease, as well as higher rates of adverse events and outcomes post interventional procedures. As a result, the odds of amputation in patients are high.

Conclusion

This survey provides data on awareness of PAD treatment options and referral of patients at high-risk of PAD/CLI to specialty care via a cross-sectional online survey of 500 clinicians from across the US. The survey results indicate that PAD awareness programs are needed in communities serving patients at high risk for PAD/CLI to increase the appropriate diagnosis and referral to specialists, including podiatric surgeons and endovascular specialists, who are uniquely suited to clinically partner with the primary care providers to establish comprehensive PAD/amputation prevention programs. Further studies/surveys should be completed to confirm the implications for improved PAD awareness and the need for expedited referrals of high risk patients.

Acknowledgments 

Financial support for the study was provided by Cardiovascular Systems, Inc. 

From ¹Cardiovascular Systems, Inc., St. Paul, Minnesota; and the ²Midwest Institute for Minimally Invasive Therapies (MIMIT), Melrose Park, Illinois.

Disclosure: Authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Drs. Martinsen and Igyarto are employees of CSI, Inc. Dr. Chopra report no conflicts of interest regarding the content herein.

Manuscript submitted April 8, 2017, final version accepted May 8, 2017.

Address for correspondence: Brad J. Martinsen, PhD, Cardiovascular Systems, Inc.1225 Old Highway 8 NW, St. Paul, MN 55112. Email: bmartinsen@csi360.com

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