Clinical characteristics and response to supervised exercise therapy of people with lower extremity peripheral artery disease

Hepatocyte growth factor for walking performance in peripheral artery disease

BACKGROUND

VM202 is a plasmid encoding two isoforms of hepatocyte growth factor. In preclinical studies, hepatocyte growth factor stimulated angiogenesis and muscle regeneration. This preliminary clinical trial tested the hypothesis that VM202 injections in gastrocnemius muscle would improve walking performance in people with mild to moderate and symptomatic lower extremity peripheral artery disease (PAD).

METHODS

In a double-blind clinical trial, patients with PAD were randomized to gastrocnemius muscle injections of either 4 mg of VM202 or placebo every 14 days for four treatments. The primary outcome was 6-month change in 6-minute walk distance. Secondary outcomes included 3-month change in treadmill walking time and gastrocnemius muscle biopsy measures. In this preliminary trial, statistical significance was prespecified as a one-sided P value of less than .10.

RESULTS

Thirty-nine participants with PAD (64.1% Black, 28.2% female) were randomized. Adjusting for age, race, smoking, and baseline performance, VM202 did not improve 6-minute walk at 6-month follow-up, compared with placebo (-13.5 m; 90% confidence interval [CI], -38.5 to +∞). At the 3-month follow-up, VM202 improved the maximum treadmill walking time (+2.38 minutes; 90% CI, +1.08 to +∞; P = .014) and increased central nuclei abundance in gastrocnemius muscle (+5.86; 90% CI, +0.37 to +∞; P = .088), compared with placebo. VM202 did not significantly improve pain-free walking distance (difference, +0.30 minutes; 90% CI, -1.10 to +∞; P = .39), calf muscle perfusion (difference, +1.80 mL/min per 100 g tissue; 90% CI, -3.80 to +∞; P = .33), or the Walking Impairment Questionnaire distance score (difference, +2.02; 90% CI, -8.11 to +∞; P = .40). In post hoc analyses, VM202 significantly improved 6-minute walk in PAD participants with diabetes mellitus at 6-month follow-up (+34.19; 90% CI, 4.04 to +∞; P = .075), but had no effect in people without diabetes (interaction P = .079).

CONCLUSIONS

These data do not support gastrocnemius injections of VM202 to improve 6-minute walk in PAD. Secondary outcomes suggested potential benefit of VM202 on skeletal muscle measures and treadmill walking, whereas post hoc analyses suggested benefit in PAD participants with diabetes.

A systematic review supporting the Society for Vascular Surgery guideline update on the management of intermittent claudication

OBJECTIVE

This systematic review and meta-analysis evaluates the current evidence on the management of intermittent claudication (IC), a prevalent manifestation of peripheral arterial disease (PAD).

METHODS

We conducted comprehensive searches of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus. We addressed six questions developed by a guideline committee from the Society for Vascular Surgery, addressing pharmacological treatments, exercise regimens, endovascular interventions, and predictors of major adverse cardiovascular, limb-related events, and mortality.

RESULTS

The search resulted in 5333 citations, from which we included 73 studies (46 randomized trials). In patients with PAD and IC who had one or more high-risk comorbidities, low-dose rivaroxaban and aspirin were associated with lower risk of major adverse limb events and major adverse cardiovascular events than aspirin alone. In patients who have undergone surgical or endovascular interventions for PAD, the addition of low-dose rivaroxaban to aspirin may improve limb outcomes. Of note, rivaroxaban trials excluded patients at high risk of bleeding. Single antiplatelet agents showed no significant efficacy differences head-to-head in ambulatory patients with IC and had a lower bleeding risk compared with combination therapy or anticoagulation. Home exercise programs were feasible and may be an alternative to supervised exercise in ambulatory patients with IC and in those who had revascularization. Several comorbidities increased the risk of adverse outcomes after revascularization for IC, such as advanced age, diabetes, coronary artery disease, chronic obstructive pulmonary disease, previous interventions, congestive heart failure, infrapopliteal artery involvement, and longer lesion lengths. In patients with IC undergoing endovascular intervention for superficial femoral artery disease, plain balloon angioplasty was associated with worse outcomes than drug elution or stent implantation for intermediate or longer lesions (ie, >5 cm).

CONCLUSIONS

This systematic review summarizes the current evidence base for the management of IC, offering insights into the relative benefits and risks of various therapeutic strategies. The findings underscore the need for individualized patient care, considering both the potential benefits and risks associated with different interventions.

Sex Differences in Peripheral Vascular Disease: A Scientific Statement From the American Heart Association

Sex differences in the risk factors, diagnosis, treatment, and outcomes of patients with cardiovascular disease have been well described; however, the bulk of the literature has focused on heart disease in women. Data on sex differences in peripheral vascular disease are ill defined, and there is a need to report and understand those sex-related differences to mitigate adverse outcomes related to those disparities. Although peripheral vascular disease is a highly diverse group of disorders affecting the arteries, veins, and lymphatics, this scientific statement focuses on disorders affecting the peripheral arteries to include the aorta and its branch vessels. The purpose of this scientific statement is to report the current status of sex-based differences and disparities in peripheral vascular disease and to provide research priorities to achieve health equity for women with peripheral vascular disease.

Safety and efficacy of home-based walking exercise for peripheral artery disease

OBJECTIVE

Home-based walking exercise is first-line therapy for peripheral artery disease (PAD), but benefits of home-based walking exercise are variable. This study evaluated whether specific clinical characteristics were associated with greater improvement after home-based walking exercise or with higher rates of serious adverse events (SAEs).

METHODS

Data were combined from two randomized clinical trials comparing home-based walking exercise with control in PAD. The home-based exercise interventions used behavioral interventions to help participants adhere to exercise. The primary outcome was the proportion of PAD participants who improved 6-minute walk (6MW) by at least 20 meters. Serious adverse events consisted of overnight hospitalizations or death that occurred during the randomized clinical trial.

RESULTS

Of 376 participants with PAD (69.6 years; 54.5% Black; 49.5% women), 217 were randomized to exercise and 159 to control. Home-based exercise improved 6MW by at least 20 meters in 100 participants (54.9%), compared with 37 (28.0%) in control (odds ratio, 3.13; 95% confidence interval, 1.94-5.06; P < .001). Age, sex, race, comorbidities, baseline 6MW, and income did not significantly alter the effect of home-based exercise on improved 6MW. SAEs occurred in 28.1% and 23.3% of participants randomized to exercise and control, respectively (P = .29). There were statistically significant interactions, indicating that home-based exercise increased SAE rates, compared with control, in Black compared with non-Black participants (P interaction < .001), in those with vs without coronary artery disease (CAD) (P interaction < .001), and in people with vs without history of heart failure (P interaction = .005).

CONCLUSIONS

Among people with PAD, home-based exercise improved 6MW by at least 20 meters in 54.9% of people. Older age, female sex, Black race, and specific comorbidities were not associated with lower rates of attaining meaningful improvement in 6MW following home-based exercise. Further study is needed to establish whether certain patient characteristics, such as history of coronary artery disease, may affect SAE rates in patients with PAD participating in home-based exercise.

Effects of Supervised Exercise Therapy on Muscle Function During Walking in Patients with Peripheral Artery Disease

BACKGROUND

Although supervised exercise therapy (SET) is a primary treatment for peripheral artery disease (PAD), the current literature is limited regarding the mechanisms contributing to increased walking distances, including how lower extremity muscle function is altered after SET. This study aimed to investigate the effects of SET on lower extremity muscle function during walking in patients with PAD.

METHODS

Twelve patients with PAD participated in a 6-month SET program consisting of three weekly exercise sessions (a total of 72 sessions) and adhered to the American College of Sports Medicine's (ACSM) recommendations. Each session started with a 5 min warm-up of mild walking and static stretching of upper and lower body muscles, followed by 50 min of intermitted exercise on a treadmill, and then finished with 5 min of cool-down activities similar to the warm-up. Each patient walked across a 10 m pathway with reflective markers on their lower limbs twice: before (baseline) and after six months of participation in SET (post-exercise). Marker coordinates and ground reaction forces were recorded and imported to OpenSim software (version 4.0) for gait simulations. Muscle force, muscle power, and metabolic rate were estimated from OpenSim and compared between the baseline and post-exercise.

RESULTS

The mean plantar flexor force was not altered after SET. However, individuals' plantar flexor muscles demonstrated improvements in force production (lateral gastrocnemius: 75-80% of stance, Cohen's d = 0.20-0.43; medial gastrocnemius: 65-85% of stance, Cohen's d = 0.20-0.71; soleus: 90-95% of stance, Cohen's d = 0.20-0.26). Furthermore, plantar flexor power increased (80-95% of stance, Cohen's d = 0.20-0.39) and this was attributed to increased power in the lateral gastrocnemius (80-85% of stance, Cohen's d = 0.20-0.47), medial gastrocnemius (80-90% of stance, Cohen's d = 0.22-0.60), and soleus muscles (85-95% of stance, Cohen's d = 0.20-0.49). Similarly, other muscle groups (knee extensors, knee flexors, hip abductors, hip adductors, hip extensors, and hip flexors) also exhibited force and power increases after SET. Additionally, force and power variances were significantly decreased in several muscle groups (plantar flexors, knee extensors, hip abductors, hip external rotators, hip extensors, and hip flexors). Total metabolic rate also increased during the stance period where muscle force and power were elevated after SET (early stance: 5-25%, Cohen's d = 0.20-0.82; mid stance: 35-45%, Cohen's d = 0.20-0.47; late stance: 75-80%, Cohen's d = 0.20-0.36).

CONCLUSIONS

Our results suggest that from a biomechanics perspective, muscle functions during walking are improved in patients with PAD after SET; however, the improvements were generally small and were not reflected by all muscle groups.

Socioeconomic factors predict successful supervised exercise therapy completion

OBJECTIVE

Supervised exercise therapy (SET) for patients with intermittent claudication (IC) can lower the risk of progression to chronic limb-threatening ischemia and amputation, while preserving and restoring functional status. Despite supporting evidence, it remains underutilized, and among those who initiate programs, attrition rates are extremely high. We hypothesize that socioeconomic factors may represent significant barriers to SET completion.

METHODS

Patients with IC referred to SET at a multi-hospital, single-institution health care system (2018-2022) from a prospectively maintained database were retrospectively analyzed. Our primary endpoint was SET program completion and graduation, defined as completion of 36 sessions. Our secondary endpoints were vascular intervention within 1 year of referral and change in ankle-brachial index (ABI). Baseline demographics were assessed using standard statistical methods. Predictors of SET graduation were analyzed using multivariable logistic regression generating adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Change in ABI was analyzed using t-test between subgroups. Reasons for attrition were tabulated. Patient Health Questionnaire-9 (PHQ-9), metabolic equivalent level, Vascular QOL, Duke Activity Status, and ABI were analyzed using paired t-tests across the entire cohort.

RESULTS

Fifty-two patients met inclusion criteria: mean age 67.85 ± 10.69 years, 19 females (36.54%), mean baseline ABI of 0.77 ± 0.16. The co-pays for 100% of patients were fully covered by primary and secondary insurance plans. Twenty-one patients (40.38%) completed SET. On multivariable analysis, residence in a ZIP code with median household income <$47,000 (aOR, 0.10; 95% CI, 0.01-0.76; P = .03) and higher body mass index (aOR, 0.81; 95% CI, 0.67-0.99; P = .04) were significant barriers to SET graduation. There were no differences in ABI change or vascular intervention within 1 year between graduates and non-graduates. Non-graduates reported transportation challenges (25.00%), lack of motivation (20.83%), and illness/functional limitation (20.83%) as primary reasons for SET attrition. Metabolic Equivalent Level (P ≤ .01) and Duke Activity Status scores (P = .04) were significantly greater after participating in a SET program.

CONCLUSIONS

Although SET participation improves lower extremity and functionality outcomes, only 40% of referred patients completed therapy in our cohort. Our findings suggest that both socioeconomic and functional factors influence the odds of completing SET programs, indicating a need for holistic pre-referral assessment to facilitate enhanced program accessibility for these populations.

Uptake and outcomes of supervised exercise therapy for peripheral artery disease: The importance of vascular medicine specialists at a large midwestern health care system during the first 5 years of CMS reimbursement

BACKGROUND

Supervised exercise therapy (SET) is the cornerstone of medical therapy for symptomatic peripheral artery disease (PAD). Despite the efficacy of SET, initial reports following the 2017 Centers for Medicare and Medicaid Services (CMS) reimbursement decision indicate low SET uptake, referral, and completion. Vascular medicine specialists are key to the success of such programs. We examined rates of SET referral, completion, and outcomes in a health system with a robust SET program during the first 5 years of CMS reimbursement.

METHODS

A retrospective chart review of patients with PAD referred to SET between October 1, 2017 and December 31, 2022 was conducted. Patient demographic and medical characteristics, SET indication, referring provider specialty, SET participation (e.g., exercise modality, number of sessions, treadmill prescription), and outcomes were abstracted. Descriptive statistics, t-tests, and multiple linear regression were used to examine the sample, evaluate outcomes, and explore outcomes by relevant covariates (i.e., age, sex, referring provider specialty).

RESULTS

Of 5320 patients with PAD, N = 773 were referred to SET; N = 415 enrolled and were included in the present study. Vascular medicine and vascular surgery specialists were the two primary sources of referrals (30.6% and 51.6%, respectively). A total of 207 patients (49.9%) completed SET. Statistically significant and clinically meaningful improvements were observed in all outcomes.

CONCLUSION

SET referral and completion rates are low in the 5 years following CMS reimbursement, despite the advocacy of vascular medicine specialists. SET is effective in improving patient functional capacity and quality of life. Additional efforts are needed to increase both SET availability and referrals as part of comprehensive treatment of PAD.

Anatomic patterns in claudicants who fail supervised exercise therapy

OBJECTIVE

Patients with intermittent claudication (IC) from peripheral arterial disease (PAD) have significant improvement with supervised exercise therapy (SET). However, many patients have progressive disease that will ultimately require revascularization. We sought to determine whether the anatomic patterns of PAD were associated with response to SET.

METHODS

We prospectively enrolled patients with IC at the West Haven, Connecticut Veterans Health Administration between June 2019 and June 2022. Patients were classified based on the level of their arterial disease with >50% obstruction. SET failure was defined as progressive symptoms or development of critical limb-threatening ischemia (CLTI) requiring revascularization.

RESULTS

Thirty-eight patients with PAD were included. Thirteen patients (34.2%) had significant common femoral artery (CFA) disease, and 25 (65.8%) had non-CFA disease. Over a median follow-up of 1407 days, 11 patients (84.6%) with CFA disease failed SET as compared with three patients (12.0%) with non-CFA disease (P < .001). Patients with CFA disease were more likely to develop CLTI (46.2% vs 4.0%; P = .001) and have persistent symptoms (38.5% vs 8.0%; P = .02). Patients with CFA disease had significantly lower post-SET ankle-brachial index (0.58 ± 0.14 vs 0.77 ± 0.19; P = .03). In multivariate analysis, the only variable associated with SET failure was CFA disease location (odds ratio, 68.75; 95% confidence interval, 5.05-936.44; P = .001).

CONCLUSIONS

Patients with IC from high-grade CFA atherosclerosis are overwhelmingly likely to fail SET, potentially identifying a subset of patients who benefit from upfront revascularization.

Disparities in Diagnosis, Treatment, and Outcomes of Peripheral Artery Disease: JACC Scientific Statement

Disparities by sex, race, socioeconomic status, and geography exist in diagnosis, treatment, and outcomes for people with lower extremity peripheral artery disease (PAD). PAD prevalence is similar in men and women, but women have more atypical symptoms and undergo lower extremity revascularization at older ages compared to men. People who are Black have an approximately 2-fold higher prevalence of PAD, compared to people who are White and have more atypical symptoms, greater mobility loss, less optimal medical care, and higher amputation rates. Although fewer data are available for other races, people with PAD who are Hispanic have higher amputation rates than White people. Rates of amputation also vary by geography in the United States, with the highest rates of amputation in the southeastern United States. To improve PAD outcomes, intentional actions to eliminate disparities are necessary, including clinician education, patient education with culturally appropriate messaging, improved access to high-quality health care, science focused on disparity elimination, and health policy changes.

Sex differences in outcomes of exercise therapy for patients with intermittent claudication: A scoping review

Exercise therapy is first-line treatment for intermittent claudication due to peripheral artery disease. We sought to synthesize the literature on sex differences in response to exercise therapy for the treatment of intermittent claudication due to peripheral artery disease. A scoping review was performed (1997 to 2023) using Ovid MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, SPORTDiscus, and Web of Science. Articles were included if they were a scientific report of any measures of health-related quality of life or walking performance after an intervention that included a structured walking program. Of the 13 studies, 11 included measures of walking distance; 7 included measures of walking time, 5 included measures of walking speed, and 4 included quality of life measures. Overall, exercise therapy resulted in significant improvements across most measures of walking performance for both men and females. When comparing magnitudes of outcome improvement by sex, results of walking-based measures were contradictory; some studies noted no difference and others found superior outcomes for men. Results of quality of life-based measures were also contradictory, with some finding no difference and others reporting substantially more improvement for females. Both men and females experienced considerable improvement in walking performance and quality of life with exercise therapy. Evidence regarding the differential effect of exercise therapy on outcomes by sex for intermittent claudication is limited and contradictory. Further efforts should be directed at using standardized interventions and metrics for measuring the outcomes that match the indications for intervention in these patients to better understand the expected benefits and any variance according to sex.

Health Disparities in Peripheral Artery Disease: A Scientific Statement From the American Heart Association

Peripheral artery disease (PAD) affects 200 million individuals worldwide. In the United States, certain demographic groups experience a disproportionately higher prevalence and clinical effect of PAD. The social and clinical effect of PAD includes higher rates of individual disability, depression, minor and major limb amputation along with cardiovascular and cerebrovascular events. The reasons behind the inequitable burden of PAD and inequitable delivery of care are both multifactorial and complex in nature, including systemic and structural inequity that exists within our society. Herein, we present an overview statement of the myriad variables that contribute to PAD disparities and conclude with a summary of potential novel solutions.

Physical Performance and Skeletal Muscle Transcriptional Adaptations Are Not Impacted by Exercise Training Frequency in Mice with Lower Extremity Peripheral Artery Disease

Exercise training is an important therapeutic strategy for lower extremity peripheral artery disease (PAD). However, the effects of different exercise frequency on physiological adaptations remain unknown. Thus, this study compared the effects of a 7-week moderate-intensity aerobic training performed either three or five times/week on skeletal muscle gene expression and physical performance in mice with PAD. Hypercholesterolemic male ApoE-deficient mice were subjected to unilateral iliac artery ligation and randomly assigned to sedentary or exercise training regimens either three or five times/week. Physical performance was assessed using a treadmill test to exhaustion. Expression of genes related to glucose and lipid metabolism, mitochondrial biogenesis, muscle fiber-type, angiogenesis, and inflammation was analyzed in non-ischemic and ischemic gastrocnemius muscles by real-time polymerase chain reaction. Physical performance was improved to the same extent in both exercise groups. For gene expression patterns, no statistical differences were observed between three or five times/week exercised mice, both in the non-ischemic and ischemic muscles. Our data show that exercising three to five times a week induces similar beneficial effects on performance. Those results are associated with muscular adaptations that remain identical between the two frequencies.

A systematic review of racial/ethnic disparities in pharmacotherapy and surgical treatment outcomes in peripheral arterial disease among African American/non-Hispanic Black, non-Hispanic White and Hispanic patients

Background

Lower extremity peripheral arterial disease (PAD) is associated with significant morbidity and mortality in racial/ethnic diverse populations. However, limited data exist on treatment outcome disparities in racial/ethnic diverse populations, particularly in AA/NHB populations.

Objective

The aim of this systematic review is to analyze disparities in the outcomes of PAD treatments, particularly pharmacotherapy and surgery, among racial/ethnic groups in the US.

Methods

A comprehensive search of original investigations pertaining to PAD treatments between 2015 and 2021 was performed. Quality assessment of the studies was also completed.

Results

Fourteen studies were included. Thirteen studies reported differences in treatment outcomes for surgical intervention, and one study reported differences for concurrent surgical and pharmacotherapy. NHB and Hispanic/Latinx ethnicities were associated with decreased overall and perioperative mortality in four studies. Six studies noted increased amputation risk among racial/ethnic diverse populations. Only one study noted significant survival benefit by race/ethnicity. Three studies noted increased risk of major adverse limb events and post-operative complications. One study noted increased limb patency after intervention in racial/ethnic cohorts. Overall, all studies reported high methodological quality with adequate assessment of outcomes and follow-up of cohort.

Conclusion

In this analysis, the predominant intervention reported is surgical. Overall, racial/ethnic populations are less likely to experience PAD-associated mortality but are more likely to experience adverse events. Further studies are necessary to include all racial/ethnic diverse populations in assessing PAD therapeutic intervention outcomes. Moreover, targeted public health efforts are necessary to increase PAD educational awareness, community-driven risk modification, and patient-centered care planning.

Near infrared spectroscopy to evaluate the effect of a hybrid exercise programme on peripheral muscle metabolism in patients with intermittent claudication: an exploratory PROSECO-IC sub study

Intermittent claudication (IC) is characterized by decreased blood flow and oxygen delivery to the lower-limb muscles, resulting in pain and impaired functional capacity. This study evaluated the effects of a 12-week hybrid walking intervention on muscle oxygenation and functional capacity in 38 patients with IC (Rutherford I-III). Functional capacity was evaluated by means of two different treadmill test protocols and a six-minute walk test (6MWT). Muscle oxygenation was assessed during the treadmill tests using near-infrared spectroscopy. After the intervention, maximal walking distance was significantly increased (p < 0.001) during the progressive maximal treadmill test (mean (SD): +155 (SD 177) metres) and 6MWT (+18 (SD 29) metres) metres, with concomitant improvements in muscle oxygenation measures. Deoxygenation was slower during the progressive maximal test (p < 0.001) and reoxygenation was faster during recovery (p = 0.045). During the more submaximal test, oxygenated haemoglobin was better preserved (p = 0.040). Slower deoxygenation was more pronounced in the high responders of the progressive maximal treadmill test (p = 0.002). The findings suggest that preserved oxygen availability and slower deoxygenation during exercise could partly explain the improvements in functional capacity.

A Systematic Review Examining the Approaches Used to Estimate Interindividual Differences in Trainability and Classify Individual Responses to Exercise Training

Background: Many reports describe statistical approaches for estimating interindividual differences in trainability and classifying individuals as "responders" or "non-responders." The extent to which studies in the exercise training literature have adopted these statistical approaches remains unclear. Objectives: This systematic review primarily sought to determine the extent to which studies in the exercise training literature have adopted sound statistical approaches for examining individual responses to exercise training. We also (1) investigated the existence of interindividual differences in trainability, and (2) tested the hypothesis that less conservative thresholds inflate response rates compared with thresholds that consider error and a smallest worthwhile change (SWC)/minimum clinically important difference (MCID). Methods: We searched six databases: AMED, CINAHL, EMBASE, Medline, PubMed, and SportDiscus. Our search spanned the aerobic, resistance, and clinical or rehabilitation training literature. Studies were included if they used human participants, employed standardized and supervised exercise training, and either: (1) stated that their exercise training intervention resulted in heterogenous responses, (2) statistically estimated interindividual differences in trainability, and/or (3) classified individual responses. We calculated effect sizes (ES_IR) to examine the presence of interindividual differences in trainability. We also compared response rates (n = 614) across classification approaches that considered neither, one of, or both errors and an SWC or MCID. We then sorted response rates from studies that also reported mean changes and response thresholds (n = 435 response rates) into four quartiles to confirm our ancillary hypothesis that larger mean changes produce larger response rates. Results: Our search revealed 3,404 studies, and 149 were included in our systematic review. Few studies (n = 9) statistically estimated interindividual differences in trainability. The results from these few studies present a mixture of evidence for the presence of interindividual differences in trainability because several ES_IR values lay above, below, or crossed zero. Zero-based thresholds and larger mean changes significantly (both p < 0.01) inflated response rates. Conclusion: Our findings provide evidence demonstrating why future studies should statistically estimate interindividual differences in trainability and consider error and an SWC or MCID when classifying individual responses to exercise training. Systematic Review Registration: [website], identifier [registration number].

Claudicating patients with peripheral artery disease have meaningful improvement in walking speed after supervised exercise therapy

OBJECTIVE

Supervised exercise therapy (SET) is a first-line treatment for patients with peripheral artery disease (PAD). The efficacy of SET is most commonly expressed by significant statistical improvement of parameters that do not clarify how each individual patient will benefit from SET. This study examined the minimal clinically important difference (MCID) in walking speed in claudicating patients with PAD after SET.

METHODS

A total of 63 patients with PAD-related claudication (Fontaine stage II PAD) participated in a 6-month SET program. Self-selected walking speed was measured before and after SET. Distribution and anchor-based approaches were used to estimate the MCID for small and substantial improvement. The ability to walk one block and the ability to climb one flight of stairs questions were chosen as anchor questions from the Medical Outcomes Study 36-item Short Form questionnaire. Receiver operating characteristics curve analyses were performed to detect the threshold for MCID in walking speed after treatment.

RESULTS

The distribution-based method estimated 0.03 m/s as a small improvement and 0.08 m/s as a substantial improvement after SET. Small and substantial improvements according to the anchor question walking one block were 0.05 m/s and 0.15 m/s, respectively. For the climbing one flight of stairs anchor question, 0.10 m/s was a small improvement. Receiver operating characteristics curve analyses identified an increase of 0.04 m/s and 0.03 m/s for improvement based on walking one block and climbing one flight of stairs, respectively.

CONCLUSIONS

We report our findings for the MCID for walking speed among claudicating patients receiving SET. Claudicating patients who increase walking speed of 0.03 m/s or greater are more likely to experience a meaningful improvement in walking impairment than those who do not. The MCID reported in this study can serve as a benchmark for clinicians to develop goals and interpret clinically meaningful progress in the care of claudicating patients with PAD.