The relationship of walking distances estimated by the patient, on the corridor and on a treadmill, and the Walking Impairment Questionnaire in intermittent claudication

Telephone Health Coaching and Remote Exercise Monitoring (TeGeCoach) in Peripheral Arterial Occlusive Disease

BACKGROUND

Supervised exercise programs are used to treat intermittent claudication (IC). Home-based exercise programs have been developed to lower barriers to participation. We studied the effects of one such exercise program (TeGeCoach) on self-reported walking ability in patients with IC.

METHODS

In a pragmatic multicenter randomized controlled trial (registration number NCT03496948), 1982 patients with symp - tomatic IC insured by one of three German statutory health insurance funds received either telephone health coaching with remote exercise monitoring (TeGeCoach; n = 994) or routine care (n = 988). The primary outcome was the change in Walking Impairment Questionnaire (WIQ) scores after 12 and 24 months in the intention-to-treat population. The secondary outcomes were healthrelated quality of life, symptoms of depression or anxiety, health competence, patient activation, alcohol use, and nicotine depen - dence.

RESULTS

There was a significant group difference in WIQ score in favor of TeGeCoach (p < 0.0001), amounting to 6.30 points at 12 months (Bonferroni-corrected 95% CI [4.02; 8.59], Cohen's d = 0.26) and 4.55 points at 24 months ([2.20; 6.91], d = 0.19). Some of the secondary outcomes also showed positive results in favor of TeGeCoach at 12 months with small effect sizes (d ≥ 0.20), including physical health-related quality of life and patient activation. The average daily step count was not higher in the TeGeCoach group.

CONCLUSION

Significant improvements regarding symptom burden demonstrate the benefit of a home-based exercise program and thus expand the opportunities for guideline-oriented treatment of IC. Future studies should additionally address the effect of home-based exercise programs on clinical variables by means of, for example, the 6-minute walk test.

Is the Walking Impairment Questionnaire a surrogate marker of 6-minute walking test performance in patients with peripheral artery disease with different degrees of claudication symptoms?

AIM

To analyze the associations between the Walking Impairment Questionnaire (WIQ) and 6-minute walk test (6MWT) in absolute or relative performance in patients with peripheral artery disease (PAD) and different degrees of claudication symptoms.

METHODS

Two hundred and sixty-seven patients with PAD and claudication symptoms participated in the study. All patients underwent 6MWT and WIQ tests. Patients were divided into tertile groups according to their 6MWT performance (1st tertile = severe, 2nd = moderate, 3rd = mild). Multiple linear regression was performed to investigate the association between WIQ scores and the achievement of expected performance in the 6MWT.

RESULTS

Claudication onset distance and time, total walking distance, and the percentage of the predicted values had a significant weak correlation ( P  < 0.01) with WIQ scores (distance, speed, and stair-climbing capacity). The correlations for almost all variables were slightly higher in the 1st tertile compared with the 2nd and 3rd tertiles (i.e. WIQ-distance and Claudication onset time, r  = 0.25 and 0.12, WIQ-distance and Claudication onset distance, r  = 0.34 and 0.18; WIQ-distance and total walking distance, r  = 0.23 and 0.18, respectively). Multilinear regression confirmed a slightly superior relationship in the 1st tertile compared with the 2nd tertile (i.e. WIQ-distance and Claudication onset time, R2  = 0.24 and R2  = 0.01; WIQ-distance and Claudication onset distance, R2  = 0.25 and R2  = 0.03, respectively).

CONCLUSIONS

WIQ is weakly associated with absolute and relative 6MWT performance in patients with PAD. Despite slightly better correlations in patients with severe claudication symptoms, WIQ scores must be used with care as a surrogate marker of 6MWT performance in this group.

Changes in standing and walking time after multimodal physical rehabilitation in low grade degenerative lumbar spondylolisthesis: a non-randomised pilot study

BACKGROUND

Surgery is often prescribed to patients with significant reduction in standing time (ST) and walking time (WT) due to degenerative lumbar spondylolisthesis (DLS). The efficacy of a multimodal physical rehabilitation protocol (MPRP) in improving ST and WT in patients with DLS is not known.

OBJECTIVE

To investigate the effect of MPRP on ST and WT in patients with DLS and compare the results with similar patients treated with other physiotherapy treatment (OPT) methods.

METHODS

Outcomes including numerical pain rating scale (NPRS) and Oswestry disability index (ODI) scores, ST and WT were compared in patients in the MPRP and OPT groups.

RESULTS

Data from 25 patients in MPRP group and 10 patients in OPT group were analyzed. In the MPRP group, the mean NPRS and ODI scores, ST, and WT improved significantly (p < .0001) after MPRP at a mean follow-up of 328 days. The mean NPRS score was significantly lower (p = .0001); mean ST (p = .03), and mean WT (p = .03) were significantly higher; and the mean NPRS improvement (p < .0001), mean ST improvement (p = .001), and mean WT improvement (p = .008) were significantly higher in MPRP group when compared to the OPT group at final follow-up.

CONCLUSION

Patients with low-grade DLS showed significant improvement in ST and WT after MPRP when compared to similar patients who underwent other physiotherapy treatments. These encouraging results indicate that MPRP can be utilized as a primary treatment option in patients with significantly reduced ST and WT due to DLS.

Effects of walking impairment on mental health burden, health risk behavior and quality of life in patients with intermittent claudication: A cross-sectional path analysis

Introduction

Intermittent claudication is the leading symptom of peripheral artery disease (leg pain when walking). The present study investigates the extent to which walking impairment is associated with health-related quality of life, mental health and health risk behavior.

Methods

A theory-based, cross-sectional path model was empirically examined using pre-intervention baseline data from a multicenter, randomized-controlled trial of patients with intermittent claudication (PAD-TeGeCoach). Data were available from 1 696 patients who completed a battery of questionnaires between April 14, 2018 and March 12, 2019, including measures of walking impairment (Walking Impairment Questionnaire), health-related quality of life (SF-12), mental burden (GAD-7, PHQ-9), nicotine- and alcohol-related risk behavior (Fagerström-Test, AUDIT-C). Sociodemographic characteristics and comorbid conditions were included in the postulated model a priori to minimize confounding effects.

Results

Walking impairment was associated with an increase in depressive (β = -.36, p < .001) and anxiety symptoms (β = -.24, p < .001). The prevalence of depressive and anxiety symptoms was 48.3% and 35.5%, respectively, with female patients and those of younger age being at greater risk. Depressive symptoms were predictive of an increased tobacco use (β = .21; p < .001). Walking impairment had adverse effects on physical quality of life, both directly (β = .60, p < .001) and indirectly mediated through depressive symptoms (β = -.16, p < .001); and indirectly on mental quality of life mediated through depressive (β = -.43, p < .001) and anxiety symptoms (β = -.35, p < .001).

Discussion

The findings underscore the need for a comprehensive treatment strategy in patients with intermittent claudication. Measures to improve walking impairment (e.g. exercise training) are key to enhance quality of life and should be the primary treatment. As a key mediator of mental quality of life, depressive and anxiety symptoms should be addressed by rigorously including mental health treatment. Risky health behaviors should be approached by promoting behavior change (e.g. smoking cessation) as a secondary prevention of peripheral artery disease.

The “Walking Estimated Limitation Stated by History” (WELSH) visual tool is applicable and accurate to determine walking capacity, even in people with low literacy level

Determination of the self-reported walking capacity by interview or standardized questionnaire is important. However, the existing questionnaires require the patient to be able to read and write in a specific language. We recently proposed the WELSH (Walking Estimated Limitation Stated by History) tool to be administrable to illiterate people. The main objective was to assess the applicability of WELSH tool in the community and in a large group. We performed a prospective study in the city of Bobo-Dioulasso in Burkina Faso during June 2020. We recruited 630 interviewers among medical students. They were trained to administer the WELSH, and to conduct a 6-minute walk test. We performed a Pearson’s “r” correlation between the WELSH and maximal walking distance (MWD). Of the 1723 participants available for the analysis, 757 (43.9%: 41.6–46.3) never went to school or attended only elementary school. The percentage of questionnaires with participant filling-in errors corrected by the investigator decreased with the decrease in educational level (p<0.001). The average WELSH score was 53 ± 22 and the average MWD was 383 ±142 meters. The Spearman correlation coefficient between the WELSH score and the MWD was r = 0.567 (p<0.001). Correlations ranged from 0.291 to 0.576 in males and females, (all p values < 0.05) and in different levels of education, with the highest coefficients found in illiterate people. The WELSH is feasible on the community by a wide variety of interviewers. It correlates with the MWD estimated by the 6-minutes’ walk test even for people with little or no schooling.

Beyond the Patient's Report: Self-Reported, Subjective, Objective and Estimated Walking Disability in Patients with Peripheral Artery Disease

Among patients with peripheral artery disease, an altered estimation of walking ability reported to the physician may influence the choice of treatment. We compared claudication distance (CD) values reported by patients or assessed by validated protocols to elaborate a formula capable of estimating more reliable values. Three hundred fifty-nine patients with claudication were measured at the time of entry into a rehabilitation program. Walking performance was obtained by patients' reports (self-reported claudication distance, SR-CD) and was directly assessed to determine the claudication and maximal walking distance by the 6-min test (6-CD and 6-MWD) and an incremental treadmill test (T-CD and T-MWD). The degree of muscle deoxygenation was objectively determined at the calf by near-infrared spectroscopy (NIRS) during the treadmill test. Among the 289 subjects analyzed, SR-CD exceeded both 6-CD and T-CD (+155 and +182 m, respectively). SR-CD was moderately correlated with T-CD (r = 0.30), 6-CD (r = 0.32), and 6-MWD (r = 0.29) but not with muscle deoxygenation per meter walked, unlike T-CD and 6-CD. A formula adjusted for the presence of diabetes reduced patient overestimation by 92%. The patient's reported claudication distance was generally overestimated compared to objective measures, and it was made more reliable through a corrective factor for easy use in a clinical setting.

Measuring walking impairment in patients with intermittent claudication: psychometric properties of the Walking Estimated-Limitation Calculated by History (WELCH) questionnaire

Objectives

Patient-reported outcome measures can facilitate the assessment of walking impairment in peripheral artery disease patients with intermittent claudication in clinical trials and practice. The aim of this study was to test the psychometric properties of the German version of the 'Walking Estimated-Limitation Calculated by History' (WELCH) questionnaire.

Methods

The assessed properties included feasibility, test-retest reliability, construct validity (i.e., convergent, divergent and known-groups validity) and responsiveness using classic psychometric methods. Psychometric properties were tested as part of a randomized controlled home-based exercise trial for patients with symptomatic peripheral artery disease at Fontaine stage IIA/B.

Results

Analyses were conducted in subgroups of 1,696 patients at baseline and 1,233 patients at 12-month follow-up (i.e., post-intervention) who completed the WELCH along with a battery of other self-report measures. The WELCH did not exhibit relevant floor or ceiling effects (< 15% achieved lowest or highest possible scores), showed evidence for good test-retest reliability (ICC = .81, 95% CI [.71-.88]) and was found to be well suited for self-completion by patients (< 5% missing data per item). WELCH scores showed moderate to strong correlations with related measures of walking impairment at both time points (Walking Impairment Questionnaire: r = .56 - .74; VascuQoL-25 activity subscale: r = .61 - .66) and distinguished well among patients with poor and high quality of life when adjusting for confounders (t = 13.67, p < .001, d = .96). Adequate divergent validity was indicated by a weaker correlation between the WELCH and general anxiety at both time points (GAD-7: r =  - .14 to  - .22). The WELCH improved by 6.61 points (SD = 17.04, 95% CI [5.13-8.10], d = 0.39) in response to exercise treatment and was able to identify large clinically important improvements observed on the walking distance (AUC = .78, 95% CI [.71-.84]) and speed subscales (AUC = .77, 95% CI [.68-.86]) of the Walking Impairment Questionnaire.

Conclusions

The WELCH is considered a feasible, reliable and valid patient-reported outcome measure for the measurement of walking impairment in patients with peripheral artery disease. The WELCH showed evidence for responsiveness to changes in walking impairment, yet further studies are warranted to conclusively determine the WELCH's ability to detect intervention effects.

Relationship between requirement to stop during a six-minute walk test and health-related quality of life, physical activity and physical performance amongst people with intermittent claudication

AIM

A simple objective test is required to identify people with impaired physical aspects of health-related quality of life (QOL) due to intermittent claudication. This study assessed the relationship of QOL, function and physical activity to the need to stop during a six-minute walking test (6MWT) amongst people with intermittent claudication.

METHOD

This was a prospective case-control study conducted at two centers in Australia. 173 participants with a history of intermittent claudication and peripheral artery disease diagnosed by ankle brachial pressure index <0.9, completed two 6MWTs one week apart. QOL was assessed with the short form (SF)-36. Physical activity was assessed by an accelerometer to record step count, stepping time and energy expenditure over 7 days. Physical performance was assessed by the Short Physical Performance Battery (SPPB) test. The associations of the need to stop at least once during the 6MWT with QOL, function and activity were assessed using Mann Whitney U test and analysis of covariates.

RESULTS

Participants that had to stop at least once during the two 6MWTs (46; 26.6%) had significantly lower scores for three of the domains (physical functioning, role-physical and bodily pain) and the physical component summary (PCS) measure of the SF-36 compared to those who did not need to stop (n = 127; 73.4%). After adjusting for the risk factor co-variates (diabetes, hypertension and ankle brachial pressure index) which were significantly unequally distributed, needing to stop during the 6MWTs was significantly associated with a lower PCS score (adjusted mean 36.5, standard error 0.8 vs. 30.5, standard error 1.3; F = 14.0; P < 0.001; partial eta squared 0.077). Participants that had to stop at least once during the two 6MWTs had significantly lower 7-day step count, time stepping and energy expenditure, but not total SPPB score, compared to those who did not need to stop.

CONCLUSIONS

Needing to stop during a 6MWT identified participants with intermittent claudication with poorer QOL and less physical activity compared to those that do not need to stop.

Use of the walking impairment questionnaire as a measure of functional assessment

Background: A significant consequence of peripheral arterial disease (PAD) is an impaired functional capacity and deteriorated quality of life. Therefore, our study aimed to investigate the usefulness of a symptom questionnaire and walk tests for the determination of the functional capacity of patients with intermittent claudication. Patients and methods: The study included 53 patients (38 males) with stable claudication distance (50-300m). A detailed history and physical examination, ankle-brachial index (ABI), treadmill exercise test, and 6-minute walk test were performed and compared to walking impairment questionnaire (WIQ). Results: Claudication distance reported from patients' history and 6-minute walk test were significantly correlated with ABI (p=0.033, p=0.044). There were no significant correlations between ABI and treadmill walk test or WIQ. Results of WIQ were significantly correlated with the history and the most of performed walk tests: treadmill initial and maximal claudication distance (p=0.004 and 0.012, respectively) and 6-minute walk test (p=0.026). 6-minute walk test was correlated with maximal claudication distance of treadmill (p=0.018), but not with an initial claudication distance. Conclusions: The validity of WIQ is comparable to walk tests and represents the useful technique for the investigation of the functional capacity of patients with PAD. A self-report based on WIQ enables a longer period of observation. It should be routinely used as a basic diagnostic tool for the estimation of the functional capacity of PAD patients with stable intermittent claudication.

Using wearable monitors to assess daily walking limitations induced by ischemic pain in peripheral artery disease

PURPOSE

To develop, assess the feasibility of, and determine the clinical validity of an event-based analysis method using wearable monitors to quantify walking pain manifestations (WPMs) and stops induced by walking pain (SIWPs) during daily life walking in people with peripheral artery disease (PAD).

METHODS

The following two conditions were studied: a standardized outdoor walking session (OWS) and a seven-day free-living measurement (FLM) period. The PAD participants (n = 23) wore an accelerometer and a watch. They were asked to press the event marker button on the watch to indicate events related to WPMs and SIWPs. To assess the clinical validity of the method, the computed pain-free walking time (PFWT) and maximal walking time (MWT) were compared with the PFWT and MWT assessed using standard treadmill walking protocols, respectively.

RESULTS

Following OWSs, the PFWT^[OWS] and MWT^[OWS] were significantly correlated with the PFWT^[Strandness] (r = .955, P < .001) and MWT^[Strandness] (r = .821, P < .001), respectively. During the FLM, PAD participants experienced only 2 WPMs/day and 1 SIWP/day, although severely limited on the treadmill and during the OWS. The average WPMs/day were moderately correlated with the PFWT^[Strandness] (r = -.54, P = .016). The PFWT^[FLM] was on average 12 times longer than the PFWT^[Strandness] . Interestingly, the intensity of the walking bouts as assessed by the accelerometer counts during the FLM was significantly lower than that during the OWS (45 ± 15 vs 66 ± 20 counts/s, P < .001).

CONCLUSION

This new method offers opportunities for studies investigating the experience of living with PAD and the assessment of daily life walking capacity for both diagnostic and therapeutic purposes.

Test-retest reliability, agreement, and minimal detectable change in the 6-minute walk test in patients with intermittent claudication

OBJECTIVE

Standardized walk tests are important for objective assessment of walking distance in patients with intermittent claudication (IC). The 6-minute walk test (6MWT) has been suggested to correlate more closely than testing on a treadmill with everyday ambulatory function, but its measurement properties have hardly been studied in IC. The aim of this study was to determine the test-retest reliability, agreement, standard error of measurement (SEM), and minimal detectable change of the 6MWT in patients with IC.

METHODS

This reliability and agreement study recruited 102 patients with stable IC (mean age, 72 ± 7.4 years; 43 women) from the vascular surgery outpatient clinic at Sahlgrenska University Hospital in Sweden. The patients performed the 6MWT twice, with at least 30 minutes of rest between tests. To determine test-retest reliability, the intraclass correlation coefficient was calculated. Bland-Altman plots were used to measure agreement.

RESULTS

The mean walking distance in both test and retest was 397.8 m (standard deviation, 81.2 m; N = 100), and the individual walking distance varied from 175 to 600 m. Excellent test-retest reliability for the 6MWT (intraclass correlation coefficient, 0.95; 95% confidence interval, 0.9-0.97) was observed. The SEM was 16.6 m (95% confidence interval, 14.6-19.3), the SEM percentage was 4.2%, and the minimal detectable change was 46 m. Five observations (5%) were positioned outside the limits of agreement; there was a small proportional bias, and the scatter of values for differences decreased as the average values increased.

CONCLUSIONS

The excellent test-retest reliability implies that it is sufficient for a patient with IC to perform the 6MWT once, at every test occasion. For the individual, an improvement or deterioration in maximum walking distance of >46 m after an intervention would be required to be 95% confident that the change is significant. Being a simple and clinically useful test, the 6MWT can be widely used to evaluate the effects of different interventions in patients with IC.

Treadmill Measured vs. Questionnaire Estimated Changes in Walking Ability in Patients With Peripheral Artery Disease

OBJECTIVE

Determining the maximum walking time (MWT) using the treadmill test is the gold standard method for evaluating walking capacity and treatment effect in patients with peripheral arterial disease (PAD). However, self reported functional disability is important when assessing quality of life. Changes in the Walking Estimated Limitation Calculated by History (WELCH) questionnaire scores were compared with the MWT.

METHODS

A cross sectional study was performed in patients with intermittent claudication. The treadmill test (3.2 km/h; 10% gradient) and WELCH questionnaire were administered to all patients for objective evaluation of walking capacity. Given the log normal distribution of these parameters in patients with PAD, a log transformation was applied to the WELCH score (LnW) and maximum walking time (LnT). The responsiveness of the WELCH score was determined using mean changes and correlation coefficients of LnW and LnT changes. The effect of time on the "estimated minus real" (E - R) changes (LnW - change minus LnT - change) was assessed after categorisation of patients into various test-retest intervals. Patients who underwent lower limb revascularisation between the two tests and those who underwent medical treatment only were analysed.

RESULTS

Correlation coefficients between LnW and LnT for tests 1 and 2 were r = 0.514 and r = 0.503, respectively (p < .001, for both). Correlation for LnW change vs. LnT change was 0.384 (p < .001). E - R was positive only early after surgery. E - R was negative for all test-retest intervals >1 year in revascularised and non-revascularised patients.

CONCLUSION

Changes in WELCH scores correlated with changes observed on the treadmill in patients with intermittent claudication. For long test-retest intervals, WELCH changes tended to overestimate the worsening of walking impairment as compared with the measured difference observed in both revascularised and non-revascularised patients. A shortlived "honeymoon" (overestimation of the benefit for the shortest test-retest interval) was observed only in revascularised patients.

Individual Patient-reported Activity Levels Before and After Joint Arthroplasty Are Neither Accurate nor Reproducible

BACKGROUND

Patients often are asked to report walking distances before joint arthroplasty and when discussing their results after surgery, but little evidence demonstrates whether patient responses accurately represent their activity.

QUESTIONS/PURPOSES

Are patients accurate in reporting distance walked, when compared with distance measured by an accelerometer, within a 50% margin of error?

METHODS

Patients undergoing THA or TKA were recruited over a 16-month period. One hundred twenty-one patients were screened and 66 patients (55%) were enrolled. There were no differences in mean age (p = 0.68), proportion of hips versus knees (p = 0.95), or sex (p = 0.16) between screened and enrolled patients. Each patient wore a FitBit Zip accelerometer for 1 week and was blinded to its measurements. The patients reported their perceived walking distance in miles daily. Data were collected preoperatively and 6 to 8 weeks postoperatively. Responses were normalized against the accelerometer distances and Wilcoxon one-tailed signed-rank testing was performed to compare the mean patient error with a 50% margin of error, our primary endpoint.

RESULTS

We found that patients' self-reported walking distances were not accurate. The mean error of reporting was > 50% both preoperatively (p = 0.002) and postoperatively (p < 0.001). The mean magnitude of error was 69% (SD 58%) preoperatively and 93% (SD 86%) postoperatively and increased with time (p = 0.001).

CONCLUSIONS

Patients' estimates of daily walking distances differed substantially from those patients' walking distances as recorded by an accelerometer, the accuracy of which has been validated in treadmill tests. Providers should exercise caution when interpreting patient-reported activity levels.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Racial differences in functional decline in peripheral artery disease and associations with socioeconomic status and education

OBJECTIVE

The objective of this study was to determine whether blacks with lower extremity peripheral artery disease (PAD) have faster functional decline than whites with PAD.

METHODS

Participants with ankle-brachial index <0.90 were identified from Chicago medical centers and observed longitudinally. Mobility impairment and the 6-minute walk were assessed at baseline and every 6 to 12 months. Mobility loss was defined as becoming unable to walk up and down a flight of stairs or to walk ¼ mile without assistance.

RESULTS

Of 1162 PAD participants, 305 (26%) were black. Median follow-up was 46.0 months. Among 711 PAD participants who walked 6 minutes continuously at baseline, black participants were more likely to become unable to walk 6 minutes continuously during follow-up (64/171 [37.4%] vs 156/540 [28.9%]; log-rank, P = .006). Black race was associated with becoming unable to walk 6 minutes continuously, adjusting for age, sex, ankle-brachial index, comorbidities, and other confounders (hazard ratio, 1.45; 95% confidence interval, 1.05-1.99; P = .022). This association was attenuated after adjustment for income and education (P = .229). Among 844 participants without baseline mobility impairment, black participants had a higher rate of mobility loss (64/209 [30.6%] vs 164/635 [25.8%]; log-rank, P = .009). Black race was associated with increased mobility loss, adjusting for potential confounders (hazard ratio, 1.42; 95% confidence interval, 1.04-1.94; P = .028). This association was attenuated after additional adjustment for income and education (P = .392) and physical activity (P = .113). There were no racial differences in average annual declines in 6-minute walk, usual-paced 4-meter walking velocity, or fast-paced 4-meter walking velocity.

CONCLUSIONS

Black PAD patients have higher rates of mobility loss and becoming unable to walk for 6 minutes continuously. These differences appear related to racial differences in socioeconomic status and physical activity.

Google Maps offers a new way to evaluate claudication

BACKGROUND

Accurate determination of walking capacity is important for the clinical diagnosis and management plan for patients with peripheral arterial disease. The current "gold standard" of measurement is walking distance on a treadmill. However, treadmill testing is not always reflective of the patient's natural walking conditions, and it may not be fully accessible in every vascular clinic. The objective of this study was to determine whether Google Maps, the readily available GPS-based mapping tool, offers an accurate and accessible method of evaluating walking distances in vascular claudication patients.

METHODS

Patients presenting to the outpatient vascular surgery clinic between November 2013 and April 2014 at the Ottawa Hospital with vasculogenic calf, buttock, and thigh claudication symptoms were identified and prospectively enrolled in our study. Onset of claudication symptoms and maximal walking distance (MWD) were evaluated using four tools: history; Walking Impairment Questionnaire (WIQ), a validated claudication survey; Google Maps distance calculator (patients were asked to report their daily walking routes on the Google Maps-based tool runningmap.com, and walking distances were calculated accordingly); and treadmill testing for onset of symptoms and MWD, recorded in a double-blinded fashion.

RESULTS

Fifteen patients were recruited for the study. Determination of walking distances using Google Maps proved to be more accurate than by both clinical history and WIQ, correlating highly with the gold standard of treadmill testing for both claudication onset (r = .805; P < .001) and MWD (r = .928; P < .0001). In addition, distances were generally under-reported on history and WIQ. The Google Maps tool was also efficient, with reporting times averaging below 4 minutes.

CONCLUSIONS

For vascular claudicants with no other walking limitations, Google Maps is a promising new tool that combines the objective strengths of the treadmill test and incorporates real-world walking environments. It offers an accurate, efficient, inexpensive, and readily accessible way to assess walking distances in patients with peripheral vascular disease.

Two-year results from a randomized clinical trial of revascularization in patients with intermittent claudication

Background

Intermittent claudication is associated with significant impairment of health-related quality of life. The use of revascularization techniques to improve health-related quality of life remains controversial.

Methods

Patients with intermittent claudication due to iliac or femoropopliteal peripheral artery disease were enrolled in the IRONIC trial. They were randomized to either best medical therapy (BMT), including a structured, non-supervised exercise programme, or revascularization with either endovascular or open techniques in addition to BMT. The primary outcome was health-related quality of life at 2 years assessed using the Short Form 36 (SF-36®) questionnaire. Secondary outcomes included VascuQoL questionnaire results, treadmill walking distances and achievement of patient-specified treatment goals.

Results

Both randomized groups had improved health-related quality of life and treadmill walking distance at 2-year follow-up. Overall SF-36® physical component summary score, three SF-36® physical domain scores, overall VascuQoL score, and three of five VascuQoL domain scores showed significantly greater improvement in the group that also received invasive treatment. Intermittent claudication distance on a graded treadmill improved more in the revascularization + BMT group (117 versus 55 m; P = 0·003) whereas maximum walking distance and 6-min walk test distance were similar. Some 44 per cent of patients in the revascularization + BMT group reported they had fully achieved their treatment goal versus 10 per cent in the BMT group.

Conclusion

A revascularization strategy with unsupervised exercise improved health-related quality of life and intermittent claudication distance more than standard BMT and an unsupervised exercise programme in patients with lifestyle-limiting claudication. Registration number: NCT01219842 (http://www.clinicaltrials.gov).

Minimal correlation between physical exercise capacity and daily activity in patients with intermittent claudication

BACKGROUND

Walking capacity measured by a treadmill test (TT) reflects the patient's maximal capacity in a controlled setting and is part of the physical exercise capacity (PEC). Daily physical activity (PA) is defined as the total of actively freely produced movements per day. A lower PA level has been increasingly recognized as a strong predictor of increased morbidity and mortality in patients with intermittent claudication (IC). Recent insights suggested that an increased PEC does not automatically lead to an increase in daily PA. However, the precise relation between PEC and PA in patients with IC is still unclear.

METHODS

A cross-sectional study was conducted to assess the association between several PEC outcomes and PA in a general IC population. PEC was determined by well-established tests (Gardner-Skinner TT, a physical performance battery, a timed up-and-go test, and a 6-minute walk test distance). PA was obtained during 7 consecutive days using a triaxial accelerometer (Dynaport MoveMonitor; McRoberts BV, The Hague, The Netherlands). Five PA components (lying, sitting, standing, shuffling, and locomotion) and four parameters (total duration, number of periods, mean duration per period, and mean movement intensity per period) were analysed. Correlation coefficients between PEC and PA components were calculated.

RESULTS

Data of 46 patients were available for analysis. Patients were sedentary (sitting and lying) during 81% of the day and were physically active (standing, shuffling, and locomotion) for the remaining 19% of the time. Correlations between PEC outcomes and PA ranged from very weak (0.025) to moderate (0.663). Moderate correlations (as therefore assumed to be relevant) were only found for outcomes of both the TT and 6-minute walk test and the locomotion components of PA. For instance, functional claudication distance (measured by TT) and number of steps per day correlated reasonably well (Spearman correlation ρ = 0.663; P < .01).

CONCLUSIONS

Exercise capacity and PA correlate minimally in patients with IC. PA may be preferred as a novel outcome measure and future treatment target in patients with IC.

Self-administered versus interview-based questionnaires among patients with intermittent claudication: Do they give different results? A cross-sectional study

CONTEXT AND OBJECTIVE

Many clinical investigations use generic and/or specific questionnaires to obtain information about participants and patients. There is disagreement about whether the administration method can affect the results. The aim here was to determine whether, among patients with intermittent claudication (IC), there are differences in the Walking Impairment Questionnaire (WIQ) and European Quality of Life-5 Dimension (EQ-5D) scores with regard to: 1) the questionnaire administration method (self-administration versus face-to-face interview); and 2) the type of interviewer (vascular surgeon, VS, versus general practitioner, GP).

DESIGN AND SETTING

Cross-sectional observational multicenter epidemiological study carried out within the Spanish National Health Service.

METHODS

1,641 evaluable patients with IC firstly completed the WIQ and EQ-5D questionnaires and then were interviewed by their doctor on the same day. Pearson correlations and Chi-square tests were used.

RESULTS

There was a strong correlation (r > 0.800; P < 0.001) between the two methods of administering the WIQ and EQ-5D questionnaires, and between the VS and GP groups. Likewise, there was a high level of concordance (P > 0.05) between the different dimensions of the WIQ-distance and EQ-5D (self-administration versus face-to-face) in the VS and GP groups.

CONCLUSION

There was no difference between the different methods of administering the WIQ and EQ-5D questionnaires, among the patients with IC. Similarly, the two types of interviewers (VS or GP) were equally valid. Therefore, it seems unnecessary to expend effort to administer these questionnaires by interview, in studies on IC.

Agreements and discrepancies between the estimated walking distance, nongraded and graded treadmill testing, and outside walking in patients with intermittent claudication

BACKGROUND

Disease severity in patients with intermittent claudication (IC) is often assessed using walking distances and treadmill tests. The aim of this study was to determine the agreement between walking distance as estimated by the patient, as measured during outside walking, and as determined using a nongraded treadmill protocol (NGTP), and an incremental graded (Gardner-Skinner) treadmill protocol (GSP).

METHODS

In this prospective observational study, 30 patients with IC estimated their maximal walking distance (MWD) and completed a "Walking Impairment Questionnaire" (WIQ). Outside walking was determined using a measuring wheel and a GSP controlled device. Primary outcomes were differences in MWD and variability (coefficient of variation, COV). Secondary outcomes were results of WIQ and differences in walking speed.

RESULTS

Estimated walking distance was significantly higher than MWD as objectively measured during outside walking (400 m vs. 309 m, respectively, P = 0.02). A substantial variability (COV = 55%) was found between both parameters. A small 35-m MWD difference between outside walking and GSP was found with a substantial scatter (COV = 42%). In contrast, a much larger 122-m MWD difference was present between outside walking and NGTP (COV = 89%). Patients walked significantly faster in the open air than on treadmills (median outside walking speed = 3.8 km/hr, GSP = 3.2 km/hr, NGTP = 2.8 km/hr; P < 0.001).

CONCLUSIONS

An incremental graded (Gardner-Skinner) treadmill protocol demonstrated the best agreement to outside walking. Discrepancies between treadmill tests and outside walking may be explained by a difference in walking speed. A single determination of a walking distance is a poor reflection of true walking capacity.

Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication

Purpose

The minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).

Methods

In this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. In addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.

Results

For the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), we found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.

Conclusion

In this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care.

Electronic supplementary material

The online version of this article (doi:10.1007/s00270-015-1060-0) contains supplementary material, which is available to authorized users.

Comparison between subjective and objective methods to assess functional capacity during clinical treatment in patients with intermittent claudication

Objective

To analyze if there is any relation between functional capacity assessed by subjective and objective methods regarding the current state and after clinical treatment in patients with intermittent claudication.

Methods

A total of 500 patients with intermittent claudication were enrolled. All patients underwent clinical examination and a functional evaluation by subjective (clinical visit) and objective method (treadmill test). Additionally, 50 patients were selected to evaluate the effect of clinical treatment by subjective and objective methods in relation to functional capacity.

Results

Out of 500 patients, only 60 (12.0%) had similar results in both methods. The remaining, that is 440 patients (88.0%) had subject values in disagreement with stress test findings. Regarding the clinical effect of the treatment on the functional outcomes, results were similar in both methods (χ²=1.7; p=0.427).

Conclusion

Although the subjective method overestimates the functional capacity when compared to the objective method, no significant differences were observed between both methods when analyzing the effect of clinical treatment. Thus, the subjective method provides similar information as compared with objective method, in monitoring the clinical treatment of patients with intermittent claudication.

Improved Quality of Life After 1 Year With an Invasive Versus a Noninvasive Treatment Strategy in Claudicants

Background—

The quality of evidence for invasive revascularization in intermittent claudication is low or very low. This prospective, randomized, controlled study tested the hypothesis that an invasive treatment strategy versus continued noninvasive treatment improves health-related quality of life after 1 year in unselected patients with intermittent claudication.

Methods and Results—

After clinical and duplex ultrasound assessment, unselected patients with intermittent claudication requesting treatment for claudication were randomly assigned to invasive (n=79) or noninvasive (n=79) treatment groups. Primary end point was health-related quality of life after 1 year, assessed with Medical Outcomes Study Short Form 36 version 1 and Vascular Quality of Life Questionnaire, and secondary end points included walking distances on a graded treadmill. The Medical Outcomes Study Short Form 36 version 1 physical component summary ( P <0.001) and 2 Medical Outcomes Study Short Form 36 version 1 physical subscales improved significantly more in the invasive versus the noninvasive treatment group. Overall, Vascular Quality of Life Questionnaire score ( P <0.01) and 3 of 5 domain scores improved significantly more in the invasive versus the noninvasive treatment group. Intermittent claudication distance improved significantly in the invasive (+124 m) versus the noninvasive (+50 m) group ( P =0.003), whereas the change in maximum walking distance was not significantly different between groups.

Conclusions—

An invasive treatment strategy improves health-related quality of life and intermittent claudication distance after 1 year in patients with stable lifestyle-limiting claudication receiving current medical management. Long-term follow-up data and health-economic assessments are warranted to further establish the role for revascularization in intermittent claudication.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01219842.

Vascular Reactivity Is Impaired and Associated With Walking Ability in Patients With Intermittent Claudication

We verified whether vascular reactivity is impaired and whether there is any association between vascular reactivity, walking ability, and peripheral artery disease (PAD) severity in patients with intermittent claudication (IC). We studied 63 patients and 17 age- and sex-matched volunteers without PAD. Vascular reactivity was evaluated in the brachial artery during reactive hyperemia (flow-mediated dilation [FMD]) and after a sublingual single dose of nitroglycerin (nitroglycerin-induced vasodilation [NID]). Walking ability was verified by a 6-minute walk test. Vascular reactivity and walking ability were significantly worse in patients with IC compared with control participants. The ankle–brachial index correlated with FMD, NID, as well as total and pain-free distances. The NID and walking ability progressively decreased as PAD severity increased. Walking ability correlated with NID but not with FMD. In patients with IC, vascular reactivity is impaired and is related to the severity of PAD and to walking ability.

Applicability of global positioning system for the assessment of walking ability in patients with arterial claudication

OBJECTIVE

This study determined for the first time the clinical applicability of a global positioning system (GPS)-monitored community-based walking ability assessment in a large cohort of patients with peripheral artery disease (PAD).

METHODS

A multicenter study was conducted among PAD patients who complained of intermittent claudication. Patients equipped with a GPS device performed a community-based outdoor walk. We determined the number of technically satisfactory GPS recordings (attempt No. 1). Patients with unsatisfactory GPS recordings were asked to perform a second attempt (attempt No. 2). From the satisfactory recordings obtained after attempts No. 1 and No. 2, we analyzed several GPS parameters to provide clinical information on the patients' walking ability. Results are reported as median (interquartile range).

RESULTS

A total of 218 patients performed an outdoor walk. GPS recordings were technically satisfactory in 185 patients (85%) and in 203 (93%) after attempts No. 1 and No. 2, respectively. The highest measured distance between two stops during community walking was 678 m (IQR, 381-1333 m), whereas self-reported maximal walking distance was 250 m (IQR, 150-400 m; P < .001). Walking speed was 3.6 km/h (IQR, 3.1-3.9 km/h), with few variations during the walk. Among the patients who had to stop during the walk, the stop durations were <10 minutes in all but one individual.

CONCLUSIONS

GPS is applicable for the nonsupervised multicenter recording of walking ability in the community. In the future, it may facilitate objective community-based assessment of walking ability, allow for the adequate monitoring of home-based walking programs, and for the study of new dimensions of walking in PAD patients with intermittent claudication.

Physical activity monitoring in patients with peripheral arterial disease: validation of an activity monitor

OBJECTIVES

The daily life physical activity (PA) of patients with peripheral arterial disease (PAD) may be severely hampered by intermittent claudication (IC). From a therapeutic, as well as research, point of view, it may be more relevant to determine improvement in PA as an outcome measure in IC. The aim of this study was to validate daily activities using a novel type of tri-axial accelerometer (Dynaport MoveMonitor) in patients with IC.

METHODS

Patients with IC were studied during a hospital visit. Standard activities (locomotion, lying, sitting, standing, shuffling, number of steps and "not worn" detection) were video recorded and compared with activities scored by the MoveMonitor. Inter-rater reliability (expressed in intraclass correlation coefficients [ICC]), sensitivity, specificity, and positive predictive values (PPV) were calculated for each activity.

RESULTS

Twenty-eight hours of video observation were analysed (n = 21). Our video annotation method (the gold standard method) appeared to be accurate for most postures (ICC > 0.97), except for shuffling (ICC = 0.38). The MoveMonitor showed a high sensitivity (>86%), specificity (>91%), and PPV (>88%) for locomotion, lying, sitting, and "not worn" detection. Moderate accuracy was found for standing (46%), while shuffling appeared to be undetectable (18%). A strong correlation was found between video recordings and the MoveMonitor with regard to the calculation of the "number of steps" (ICC = 0.90).

CONCLUSIONS

The MoveMonitor provides accurate information on a diverse set of postures, daily activities, and number of steps in IC patients. However, the detection of low amplitude movements, such as shuffling and "sitting to standing" transfers, is a matter of concern. This tool is useful in assessing the role of PA as a novel, clinically relevant outcome parameter in IC.