Identifying Gaps in Disease Knowledge among Patients with Peripheral Artery Disease

Abstract

Introduction:

An individual’s understanding of disease risk factors and outcomes is important for the ability to make healthy lifestyle choices and decisions about disease treatment. Peripheral artery disease (PAD) is a condition with increasing global prevalence and high risk of adverse patient outcomes. This study seeks to understand the adequacy of disease understanding in patients with PAD.

Methods:

This was an observational study of patients with PAD recruited from vascular surgery outpatient clinic and PAD clinical studies at a single academic medical center over an 8-month period. A 44-item paper survey assessed demographic and socioeconomic information, knowledge of personal medical history, PAD risk factors, consequences of PAD, and health education preferences. Patients with documented presence of PAD were offered the survey. Patients unable to complete the survey or provide informed consent were not considered eligible. Disease “awareness” was defined as correct acknowledgement of the presence or absence of a disease, including PAD, in the personal medical history. “PAD knowledge score” was the percentage of correct responses to questions on general PAD risk factors and consequences. Of 126 eligible patients, 109 participated. Bivariate analysis was used to study factors associated with awareness of PAD diagnosis. Factors associated with the PAD knowledge score were studied using the Pearson correlation coefficient, two-sample T-test, or one-way ANOVA. P value < .05 was considered statistically significant.

Results:

Mean participant age was 69.4 ± 11.0 years and 39.4% (N=43) were female. Most participants (78.9%; N=86) had critical limb-threatening ischemia. Only 65.4% (N=70) of participants were aware of a diagnosis of PAD, which was less than their awareness of related comorbidities. Factors positively associated with PAD diagnosis awareness were female sex (81.4% vs. 54.7%; P=.004) and history of percutaneous leg revascularization (78.6% vs. 47.9%; p=.001). Among 17 patients who had undergone major leg amputation, 35% (N=6) were unaware of a diagnosis of PAD. PAD knowledge scores correlated positively with an awareness of PAD diagnosis (59.1% vs. 48.7%; P=.02) and negatively with a history of hypertension (53.4% vs. 68.1%; P=.001). Most participants (86.5%; N=90) expressed a desire to be further educated on PAD. The most popular education topics were dietary recommendations, causes, and treatment for PAD.

Conclusion:

Patients with PAD have deficits in their awareness of this diagnosis and general knowledge about PAD. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.

Table of Contents Summary

In this single-center observational study, patients with documented PAD have significant gaps in awareness of their PAD diagnosis and general knowledge about PAD. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.

INTRODUCTION

Peripheral artery disease (PAD) is a clinical manifestation of atherosclerosis that affects arterial perfusion of the lower extremities and can lead to claudication and critical limb threatening ischemia. PAD affects 230 million people globally, including 8.5 million Americans.(1,2) Patients with PAD can suffer from impaired activity, decreased quality of life, and limb loss.(3–5) PAD also results in a 3–5-fold relative risk for stroke, myocardial infarction, and all-cause mortality compared to patients without PAD.(6) National lipid management guidelines consider PAD to be a coronary artery disease risk equivalent.(7)

Despite the high prevalence and increased risk of cardiovascular morbidity and mortality associated with PAD, general knowledge of PAD has historically been shown to be limited. In a 2007 survey of over 2,500 American adults in the general population older than 50 years of age, only 25% expressed familiarity with PAD, in contrast to 67% who expressed familiarity with coronary artery disease, stroke, and heart failure.(8) Furthermore, among the participants who were aware of PAD (defined as awareness of the terms “peripheral artery disease,” “PAD,” or “peripheral vascular disease”), only half knew that diabetes and smoking are risk factors of PAD, 25% knew that PAD is associated with increased risk of myocardial infarction and stroke, and 14% knew that PAD could result in amputation. In a 2003 study, patients with established PAD were less aware that PAD is associated with high risk of stroke, myocardial infarction, and death compared to patients without PAD, suggesting PAD-specific gaps in knowledge.(9) Gaps in knowledge of PAD among the general public, PAD patients, and medical practitioners have also been described in Canada,(10,11) Saudi Arabia,(12) the Netherlands,(13,14) Sweden,(15) and France,(16) suggesting a global problem in PAD knowledge.

Since global prevalence of PAD is increasing(1,17) and prior studies have demonstrated low public awareness of PAD, the purpose of this study was to quantify patient understanding of their PAD diagnosis and identify their preferences for PAD education interventions using a contemporary cohort of patients with PAD. The results of this study can be used to formulate and improve patient education initiatives that will reduce the risk of adverse cardiovascular and limb events.

METHODS

Study design

This was an observational study of patients with PAD. The Northwestern University Institutional Review Board approved the protocol. All participants provided written informed consent prior to survey completion.

Recruitment and inclusion and exclusion criteria

Participants were a convenience sample of patients with a known diagnosis of PAD recruited from the vascular surgery outpatient clinic at Northwestern Memorial Hospital between May and December 2020. Inclusion criteria were the presence of PAD, defined as ABI ≤ 0.9; a history of leg revascularization or amputation for PAD; or a report from a certified vascular laboratory indicating the presence of PAD. Exclusion criteria were inability to provide informed consent or complete the paper survey. Eligible patients were approached about the survey in clinic after they had finished seeing the vascular provider. Participants who provided informed consent to participate in the study completed the survey in the clinic or waiting area.

Additional participants were identified from two PAD research studies between October 2020 and January 2021: an observational study, Mitochondrial Dysfunction in PAD (MDD), and a clinical trial, Promote Weight Loss in Obese PAD Patients to Prevent Mobility Loss (PROVE; ClinicalTrials.gov identifier NCT04228978). The same inclusion and exclusion criteria were applied to this sample. These participants mailed in the completed surveys. Consecutively eligible participants in both studies were asked to participate in this study in order of study visits or enrollment date.

Regardless of enrollment strategy, each participant completed the survey once.

Measures of participant awareness of health history and medical knowledge

A 44-item paper questionnaire was developed to measure participant awareness of their own medical history, general knowledge of risk factors for PAD and future risk cardiovascular and limb events, and education preferences (See Supplemental Materials). The questionnaire contained 5 questions on demographics and socioeconomic status, 15 questions on past medical and surgical history, 19 questions on general risk factors and potential consequences of PAD, and 5 questions on PAD education preferences. The questionnaire was developed using feedback from national experts in PAD or health education and pilot tested in a small group of patients with PAD.

In order to determine if participants were aware of their own medical history, the electronic medical record (EMR) was used to corroborate participant responses about personal medical history. “Awareness” of a diagnosis was defined as congruence between patient understanding of whether or not they had received a specific diagnosis (e.g., PAD, diabetes mellitus, hypertension, hyperlipidemia, transient ischemic attack, and stroke) and EMR documentation of the presence or absence of these conditions. If patients were “unsure” of a diagnosis or incorrect in their awareness that they had been diagnosed with a specific condition, this was considered incongruence. PAD symptom category (critical limb threatening ischemia [CLTI] vs. other) was determined by examining the EMR. Symptoms were classified as CLTI if this term, “critical limb threatening ischemia,” “critical limb ischemia,” or “CLI” were used by a medical practitioner in the EMR or if there was a description of rest pain, non-healing foot ulcer, or gangrene. Cigarette smoking and history of PAD education were quantified by self-report. The percentage of correct responses to the 19 questions on risk factors and potential consequences of PAD was used to calculate a “PAD knowledge score.” Participants with > 6 missing responses on these items were excluded from this portion of the analysis. “Unsure” responses to these questions were graded as incorrect, since “unsure” indicates lack of knowledge. Answer choices were designed this way so that patients would not skip questions and thus risk being excluded from the analysis.

Statistical analysis

Standard descriptive statistics were used to summarize the characteristics of the study participants. Continuous variables are presented as mean ± standard deviation and categorical variables as frequency (percentage). Bivariate analysis was used to examine factors associated with the awareness of PAD diagnosis. Age was compared between participants who were aware of a PAD diagnosis and those who were not aware based on the two-sample T-test. The chi-squared test (or Fisher’s exact in the presence of a sparse frequency table) was used to test the association between categorical variables and awareness of PAD diagnosis. A similar analysis was conducted to examine the factors associated with the PAD knowledge score. The Pearson correlation coefficient was used to test the association between the knowledge score and age. The two-sample T-test or one-way ANOVA was used to test the association between the knowledge score and categorical factors. The chi-squared test was used to compare the preferred PAD education topics and source of education between participants who wanted to learn more about PAD and were aware of a PAD diagnosis and participants who were not aware. A P value < .05 was considered statistically significant. There is no adjustment for multiple testing applied. SAS® software version 9.4 was used for all analyses.

RESULTS

Study cohort

A total of 109 completed surveys were collected from 126 eligible participants (see flowchart in Fig 1), for a survey response rate of 85.2%. Baseline participant characteristics are shown in Table I. Overall mean participant age was 69.4 years ± 11.0, 39.4% (N=43) were female, and most participants (78.9%, N=86) had CLTI. All participants recruited from vascular surgery clinic (N=99) had an established diagnosis of PAD (i.e., no patients received a new diagnosis of PAD on the same day as survey administration). Approximately 40% (N=46) of participants had achieved at least college-level education and approximately half (N=54) had an annual household income of at least $25,000.

Fig 1.

Flowchart of participants who met inclusion and exclusion criteria. MDD, Mitochondrial Dysfunction in PAD. PROVE, Promote Weight Loss in Obese PAD Patients to Prevent Mobility Loss

Table I.

Cohort characteristics (N=109).

Characteristic
Age (years)	69.4±11.0
Female sex	43 (39.4%)
Race
Caucasian	62 (56.9%)
African-American	38 (34.9%)
Other	9 (8.3%)
Highest level of education
Master’s degree or higher	18 (16.5%)
College	28 (25.7%)
Some college or technical school	27 (24.8%)
High school	26 (23.9%)
Did not graduate from high school	6 (5.5%)
Annual household income
> $60,000	32 (29.4%)
$25–$60,000	22 (20.2%)
< $25,000	31 (28.4%)
Unsure or prefer not to answer	11 (10.1%)
Living situation
Home	98 (90.0%)
Assisted living facility or nursing home	4 (3.7%)
No permanent home address	3 (2.8%)
Other	2 (1.8%)
Ambulatory status
Can ambulate without assistance	58 (53.2%)
Can ambulate with assistance	32 (29.4%)
Non-ambulatory	13 (11.9%)
Smoking
Current	12 (11.0%)
Former	68 (62.4%)
Never	26 (23.9%)
PAD symptoms
Critical limb-threatening ischemia	86 (78.9%)
Other	23 (21.1%)

ABI, ankle-brachial index. PAD, peripheral artery disease.

Data expressed as mean ± standard deviation or N (percentage).

Participant awareness of personal health history

All participants were known to have PAD, but despite the high prevalence of CLTI among participants, only 70 (64.2%) responded correctly when asked “Do you have PAD?” In order to address potential unfamiliarity with this abbreviation, a subset of 43 participants who received a later version of the questionnaire were also asked this question using a layman’s explanation of PAD (“Do you have blockages or narrowing in the blood vessels in your legs?”), but the fraction of correct responses was similar at 62.8% (N=27). Even after accounting for missing data in the EMR, awareness of the diagnosis of related and highly prevalent comorbidities, including diabetes mellitus (88.7%), transient ischemic attack or stroke (88.7%), hypertension (79.2%), and hyperlipidemia (73.6%), was greater than awareness of a PAD diagnosis, suggesting PAD-specific knowledge deficits (Table II).

Table II.

Awareness of personal health history

		Correct responses
Overall awareness of PAD diagnosis		64.2% (70/109)
Awareness of other diagnoses*			Awareness of PAD diagnosis
Diagnosis	Prevalence	Correct responses
Diabetes mellitus	56/106 (52.8%)	88.7% (94/106)	63.2% (67/106)
TIA or stroke	24/106 (22.6%)	88.7% (94/106)	63.2% (67/106)
CABG or coronary PCI	32/106 (30.2%)	84.0% (89/106)	63.2% (67/106)
Hypertension	88/106 (83.0%)	79.2% (84/106)	63.2% (67/106)
Hyperlipidemia	84/106 (79.2%)	73.6% (78/106)	62.3% (66/106)

^*Denominator excludes missing data in electronic medical record

TIA, transient ischemic attack. CABG, coronary artery bypass graft. PCI, percutaneous coronary intervention

Variables associated with awareness of a PAD diagnosis on bivariate analysis were female sex (81.4% vs 54.7% in males; P=.004) and a history of percutaneous leg revascularization (78.6% vs. 47.9% if no history of percutaneous leg revascularization; P=.001). There was decreased frequency of PAD diagnosis awareness among participants with diabetes than those without (59.3% vs. 70%; P=.25) and increased frequency of PAD diagnosis awareness among those who had any history of leg revascularization (open and percutaneous) than those without (68.9% vs. 53.3%; P=.13), but these did not reach statistical significance. Of the 17 patients who had undergone major amputation as a consequence of PAD, only 11 (64.7%) were aware of their PAD diagnosis, which was similar to the fraction of patients without a history of major amputation (64.4%; N=56/87). Complete results from bivariate analysis is shown in Table III.

Table III.

Bivariate analysis of variables associated with awareness of PAD diagnosis

Variable	Frequency	P value
Age (years), mean ± SD		.43
Aware of PAD diagnosis	70.2±10.6
Unaware of PAD diagnosis	68.5±10.3
Female sex	35/43 (81.4%)	<.01
Male sex	35/64 (54.7%)
Race
Caucasian	40/62 (64.5%)	.91
Non-Caucasian	26/41 (63.4%)
Highest education level attained		.68
High school or some college	37/59 (62.7%)
College degree or higher	30/45 (66.7%)
Annual household income		.33
≤ $60K	32/52 (61.5%)
> $60K	23/32 (71.9%)
Comorbidities
Diabetes	32/54 (59.3%)	.25
No diabetes	35/50 (70%)
Hypertension	56/86 (65.1%)	.75
No hypertension	11/18 (61.1%)
Hyperlipidemia	55/82 (67.1%)	.21
No hyperlipidemia	11/21 (52.4%)
Smoking	7/12 (58.3%)	.75
Non or former smoker	60/92 (65.2%)
PAD surgery history
History of percutaneous leg revascularization	44/56 (78.6%)	<.01
No history of percutaneous leg revascularization	23/48 (47.9%)
History of surgical bypass	23/38 (60.5%)	.53
No history of surgical bypass	44/66 (66.7%)
History of major amputation	11/17 (64.7%)	.98
No history of major amputation	56/87 (64.4%)
History of minor amputation	14/25 (56.0%)	.36
No history of minor amputation	51/77 (66.2%)
History of any leg revascularization	51/74 (68.9%)	.13
No history of any leg revascularization	16/30 (53.3%)
History of any amputation	20/34 (58.8%)	.47
No history of any amputation	45/68 (66.2%)
History of leg revascularization or major amputation	51/76 (67.1%)	.35
No history of leg revascularization or major amputation	16/28 (57.1%)
PAD symptoms		.59
Claudication	16/23 (69.6%)
Rest pain or tissue loss	52/82 (63.4%)
Ambulatory status		.82
Ambulates independently	39/58 (67.2%)
Ambulates with assistive device	19/31 (61.3%)
Non ambulatory	9/13 (69.2%)

Bold indicates P<.05.

Participant knowledge of PAD

General knowledge of risk factors for PAD (11 questions) in all participants and in participants stratified by awareness of their PAD diagnosis is shown in Supplemental Table IA. The percentage of correct responses among all participants ranged from 9.3% to 75.7% and largely did not depend on participant awareness of their PAD diagnosis. However, participants who were aware of their PAD diagnosis were more likely to know that smoking is a risk factor for PAD (81.8%) than participants who were unaware of their PAD diagnosis (58.8%; P=.01).

General knowledge of potential consequences of PAD (8 questions) is shown in Supplemental Table IB. Overall, knowledge of potential consequences among all participants was greater (range of percentage of correct responses 24–85.7%) than knowledge of risk factors. When participants were stratified by awareness of their PAD diagnosis, participants who were aware of their diagnosis were more likely to recognize lower extremity pain (P<.01), walking impairment (P<.01), and stroke (P=.02) as potential consequences of PAD than those who were unaware of their diagnosis. Knowledge of risk of death due to PAD was not associated with awareness of PAD diagnosis.

General PAD knowledge was quantified by the “PAD knowledge score,” the percentage of correct responses to the 19 survey questions on PAD risk factors and consequences (possible range 0–100%). Three participants were excluded from this analysis due to missing responses. The mean PAD knowledge score of the remaining participants was 55.7 ± 22.2% (range 0–95%). The distribution of scores is shown in Fig 2.

Fig 2.

Distribution of PAD knowledge scores among 106 participants. PAD knowledge score represents the percentage of correct responses on 19 survey questions on PAD risks and potential consequences. Line represents fitted normal curve.

Bivariate analysis of factors associated with the PAD knowledge score is shown in Table IV. Awareness of a PAD diagnosis was associated with significantly higher scores (59.1 ± 20.4 vs. 48.7 ± 24.1; P=.02), while a history of hypertension was associated with significantly worse scores (53.4±22.7 vs. 68.1±13.0; P<.01). Participants with a history of major amputation for PAD also had higher scores than those without amputation (65.0 ± 16.3 vs. 54.2 ± 22.6; P=.06), although this did not reach statistical significance. We did not observe any significant associations between age, sex, annual household income, and education background with the knowledge score.

Table IV.

Bivariate analysis PAD knowledge score

	Correlation coefficient	P value
Age	−0.125	.20
Variable	Mean score±SD	P value
Female sex	57.5±23.6	.50
Male sex	54.5±21.3
Race		.30
Caucasian	57.3±22.8
Non-Caucasian	52.6±21.6
Highest education level attained		.99
High school or some college	55.7±22.5
College degree or higher	55.6±22.5
Annual household income		.49
≤ $60K	56.5±22.7
> $60K	59.9±22.1
Comorbidities
Diabetes	52.8±25.1	.12
No diabetes	59.5±17.5
Hypertension	53.4±22.7	<.01
No hypertension	68.1±13.0
Hyperlipidemia	55.3±23.4	.57
No hyperlipidemia	58.4±16.2
Smoking	53.1±20.6	.59
Non or former smoker	56.7±22.2
PAD surgery history
History of percutaneous leg revascularization	55.3±23.5	.72
No history of percutaneous leg revascularization	56.8±20.4
History of surgical bypass	60.3±19.0	.12
No history of surgical bypass	53.3±23.4
History of major amputation	65.0±16.3	.06
No history of major amputation	54.2±22.6
History of minor amputation	56.4±21.8	.82
No history of minor amputation	55.3±22.2
History of any leg revascularization	56.9±22.5	.53
No history of any leg revascularization	53.9±20.9
History of any amputation	58.7±21.5	.31
No history of any amputation	54.0±22.2
History of leg revascularization or major amputation	56.9±22.2	.50
No history of leg revascularization or major amputation	53.6±21.7
PAD symptoms		.72
Claudication	54.5±17.5
Rest pain or tissue loss	56.4±23.0
Ambulatory status		.54
Ambulates independently	58.4±19.3
Ambulates with assistive device	53.1±27.1
Non ambulatory	54.7±22.7
Aware of PAD diagnosis	59.1±20.4	.02
Not aware of PAD diagnosis	48.7±24.1

Bold indicates P<.05.

In the subset of participants who were aware of their PAD diagnosis (N=69), the PAD knowledge score was again lower among those with hypertension (58.8 ± 21.0 vs. 64.1 ± 14.3; P<.01). The knowledge score was higher among those who had undergone major amputation (71.1 ± 14.9 vs. 57.7 ± 20.1; P=.05), any amputation (66.2 ± 16.9 vs. 53.2 ± 22.9; P=.06), and coronary artery bypass grafting (70.7 ± 15.4 vs. 58.0 ± 20.1; P=.07), but these did not reach statistical significance.

In the subset of participants who were unaware of their PAD diagnosis (N=36), diabetes (43.1 ± 26.9 vs. 57.5 ± 16.3; P=.08) and hypertension (45.0 ± 24.7 vs. 63.9 ± 15.1; P=.06) were associated with lower scores, while a history of coronary stenting was associated with higher scores (66.3 ± 9.6 vs. 45.8 ± 24.7; P=.08), although none of these reached statistical significance.

Education preferences

Of participants who reported having a vascular surgeon (N=103), the majority (N=75; 72.8%) indicated that they had received some form of PAD education from their surgeon. However, the majority of all participants (N=90/104; 86.5%) expressed a desire to learn more about PAD, which was not associated with awareness of PAD diagnosis or having a vascular surgeon. Furthermore, awareness of a PAD diagnosis was not associated with having a vascular surgeon, suggesting that the education the subset of vascular surgery participants received was not effective enough to be retained. The current education paradigm used in the vascular clinic at the study medical center is ad hoc verbal education by a physician or advanced practice nurse with distribution of an adjunctive printed patient education material. However, of the 99 participants recruited from vascular clinic, only 32 (32.3%) recalled having received printed patient education materials about PAD. PAD topics that participants indicated an interest in learning about are shown in Supplemental Table IIA. The top 3 most popular topics were dietary recommendations, causes, and treatment for PAD. Interestingly, patients who were aware of their diagnosis were more likely to be interested in learning about behavior and health conditions associated with PAD than those who were not aware of their diagnosis (58.5% vs. 39.3%; P=0.1). Although this did not reach statistical significance, it suggests that awareness of the diagnosis is associated with an interest in behavioral change.

Nearly 70% of participants who had a vascular surgeon and expressed interest in learning more about PAD (N=90) reported interest in learning more about PAD from their surgeon. Paper and online resources were the next most popular choices overall for education preferences. Approximately half of patients were willing to travel to learn more about PAD and a third of participants expressed interest in attending a patient education conference and/or were willing to pay to learn more about PAD. Interestingly, patients who were not aware of their diagnosis were more likely to prefer learning about PAD from their primary care physician, although this did not reach statistical significance. Preferences on source of PAD education are shown in Supplemental Table IIB.

DISCUSSION

The central findings of this observational study of participants with a known diagnosis of PAD are: (1) awareness of the presence of PAD in patients with documented PAD was low (64.2%) and comparatively lower than awareness of the presence or absence of related comorbidities such as hypertension, hyperlipidemia, stroke, and diabetes; (2) general knowledge of PAD risk factors and potential consequences was low but positively correlated with an awareness of a PAD diagnosis; and (3) the majority of participants expressed a desire to learn more about PAD despite having received some form of PAD education from their providers.

Previous reports have also documented low rates of PAD awareness in both the general public(8,11,18) and PAD patients.(9,13,15) In a study by McDermott et al. (2003),(9) participants were divided into a non-PAD group (n=142), a PAD group (n=136), and a coronary artery disease group (n=70). The study found that compared with the other groups, patients in the PAD group were more likely to underestimate the risk of cardiovascular comorbidities associated with a diagnosis of PAD, including myocardial infarction and cerebrovascular accidents. It also found that patients in the coronary artery disease group were significantly more likely to believe cholesterol lowering medication was important for patients with PAD than patients in the PAD group (75.8% vs 57.5%; P=0.005). Builyte et al.(19) similarly observed that patients with PAD had less atherosclerosis-specific knowledge and overall health literacy compared to patients with coronary artery disease. In qualitative studies of claudicants, respondents failed to recognize that claudication is a sign of systemic atherosclerosis and the role of exercise and diabetes in their disease.(13,20)

Knowledge of PAD in the general public is also low. Hirsch et. al (2007)(8) studied PAD knowledge gaps in a nationally representative phone survey of 2,500 adults in the US. Only 25% of respondents had familiarity with PAD, which was significantly lower than the familiarity with other cardiovascular diseases including stroke (73.9% familiarity) and coronary artery disease (67.1% familiarity). Public awareness of PAD was lower than for uncommon diseases including amyotrophic lateral sclerosis (36.3% familiarity) and multiple sclerosis (42.0% familiarity). Finally, a community-based awareness campaign of 237 participants conducted in Toronto revealed that nearly 80% of participants were unaware of PAD, but the subgroup of participants who received an educational pamphlet demonstrated improved knowledge of PAD after 6 weeks compared to those who did not receive any education.(11)

There are no benchmarks for acceptable rates of diagnosis awareness among patients or the general public, but the rate of PAD diagnosis awareness we observed is lower than that observed by other investigators for patients with other conditions. In a study of 397 consecutive patients who had survived acute coronary syndrome, awareness of prior myocardial infarction, diabetes mellitus, and hypertension were all > 80%.(21) In a cross-sectional population-based study of 65,000 patients with a history of cancer, 80% correctly acknowledged this diagnosis.(22) There are similarly no benchmarks for acceptable rates of knowledge in PAD. However, in the US Department of Health and Human Services Healthy People 2020 Program, the target proportions of US adults who are aware of the early warning symptoms and signs of a heart attack and stroke were 43.6% and 59.3%, respectively. While program data suggest that these objectives were met in 2020, certain subgroups remained below target, including certain race/ethnicities and educational attainment levels.(23) Our findings support focused research into the causes for patients with PAD to lack diagnosis awareness and knowledge.

We observed a positive association between awareness of PAD diagnosis and female sex. Other investigators have reported qualitatively similar correlations between cardiovascular knowledge and female sex. In a large US population-based survey of knowledge of stroke and heart attack in the US, male sex and presence of hypertension were both associated with poor understanding of cardiovascular disease warning signs,(24) and awareness of heart attack symptoms is worse in men than in women.(25,26)

Deficiencies in PAD patient knowledge of disease may reflect behaviors that ultimately lead to poor clinical outcomes. Patients with active information-seeking behavior use different sources to obtain information, frequently ask questions, and are more knowledgeable about PAD and lifestyle changes.(27) In contrast, patients with passive information-seeking behavior are not informed enough to participate in their own care or are not invited to do so(15) and become detached from their care plan.(27) Low levels of knowledge could also reflect education strategies which are not effective (e.g., do not reflect functional health literacy, do not utilize patient teach-back,(28) or are not in patient-preferred formats). Health literacy is the degree to which participants have the ability to find, understand, and use information to inform health-related decisions and actions for themselves.(29) While participants in our study selected education preferences and 28% to 50% of participants reported a willingness to travel, pay, and/or to attend a patient education conference to learn more about PAD, we did not quantify their ability to use this information to make well-informed decisions. Given that health literacy is a central focus of Healthy People 2030, the nation’s 10-year plan for addressing the most critical public health priorities and challenges,(30) health literacy should be considered in future assessments of patient education initiatives. Furthermore, since PAD is a costly,(31) chronic, and incurable disease that is impacted by behaviors(32,33) and lifestyle, it is critical that education interventions lead to knowledge that ultimately translates into improved patient competence and confidence to self-manage their disease and engage with providers. While this has not yet been shown in patients with PAD,(34) improved patient knowledge as a consequence of education interventions is associated with increased self-efficacy for self-management in other chronic and incurable diseases, including confidence to maintain lifestyle changes and follow medical regimens.(35) While we did not perform a multivariate analysis of PAD knowledge due to the modest sample size and lack of other variables which are relevant to patient knowledge including health literacy as discussed above, the identification of PAD patient knowledge gaps and patient education preferences in this study will inform future efforts to define the factors contributing to these gaps, formulate more effective education strategies, and assess their impact on patient self-care efficacy, activation, and outcomes.

There are several limitations of this study. First, the modest sample size could lead to type II error. Unlike prior studies, we did not observe an association between awareness of PAD diagnosis or PAD knowledge with highest education level or household income levels,(8,19) possibly due to sample size or exclusion criteria which were too restrictive to allow identification of these associations. For instance, the exclusion of patients who were unable to complete the paper survey prevented us from studying PAD knowledge in patients with dementia and non-English speakers. We also did not perform multivariate analyses due to the modest sample size. However, the lack of some bivariate associations might not be the result of chance. The lack of association between history of major amputation or surgical bypass with awareness of PAD diagnosis or PAD knowledge score could suggest true deficits in vascular surgery patients. For instance, in a qualitative study of PAD patients with foot wounds who had undergone vascular surgery,(27) 65% were unaware or unsure of their PAD diagnosis, a fraction similar to what we observed in this study. Furthermore, among claudicants who had undergone leg revascularization, there was a misunderstanding that revascularization resulted in disease cure(13) and a perception that their surgeons did not explain PAD to them in language that they could understand(20) or had time for questions,(13) resulting in a lack of understanding about treatment plans and reduced likelihood of behavioral change. Our finding that 35% of patients who had undergone major amputation for PAD were unaware of the presence of PAD highlights the fact that the mode, delivery, and effectiveness of perioperative PAD education needs to be intensely scrutinized to identify the barriers to better patient understanding of PAD.

Second, the majority of participants were recruited from vascular surgery outpatient clinic at an urban academic center. Thus, the largely single-center and single-practice study design are limitations that could limit the generalizability of our observations, since other centers may have different PAD education strategies and different patient referral patterns. Furthermore, given the large proportion of participants with a history of CLTI, our findings are biased towards patients who require or have undergone revascularization and/or amputation. Moreover, study recruitment occurred during the COVID-19 pandemic in 2020, when in-person clinic visits at our medical center were restricted. Thus, study enrollment could have been biased towards patients with more severe disease or acute problems. However, numerous other studies have demonstrated that deficits in PAD knowledge transcend borders; are present in PAD patients, medical practitioners, and medical trainees alike;(10–16,36,37) lead to delays in diagnosis and treatment;(38) and are barriers to patients coping and participating in their care plans.(20,34)

Finally, the cross-sectional and observational design is a limitation. We were unable to assess temporal patterns in participant knowledge of PAD or associations between PAD knowledge with clinical events (such as surgery) or outcomes (such as smoking cessation) and we could not measure whether education interventions impact PAD knowledge gain and retention. However, the information we gained from this study will inform future research further defining PAD knowledge deficits and the optimal format, content, and strategies for PAD patient education that incorporate patients’ needs, concerns, readiness to learn, preferences, support, and possible barriers to learning.

Despite these limitations, our findings have important implications. The current patient education paradigm for PAD in our practice, and likely regionally, nationally, and globally, needs to change in order to mitigate knowledge gaps. Educational outreach programs in the general public, targeted education interventions in patients at risk for PAD, and effective education in patients with PAD need expeditious implementation to prevent delays in diagnosis, decrease cardiovascular and limb morbidity and mortality through lifestyle modification and risk reduction, and enable shared decision making with providers.

In conclusion, patients with PAD have significant gaps in awareness of their PAD diagnosis and general knowledge about PAD. These findings offer a striking picture of deficits in contemporary PAD patient education. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.

Article highlights:

Type of Research:

Single-center observational study

Key Findings:

Among 109 study participants with documented presence of PAD, awareness of a PAD diagnosis is low (65.4%) and comparatively lower than awareness of related comorbidities. General knowledge of PAD risk factors and potential consequences is also low but correlates with an awareness of a PAD diagnosis.

Take Home Message:

Patients with documented PAD have significant gaps in awareness of their PAD diagnosis and general knowledge about PAD. These findings offer a striking picture of deficits in contemporary PAD patient education. Future research priorities should further define these deficits and their causes in order to inform new strategies that foster information-seeking behavior and effective educational programs for PAD.