Gary J. Martin

Measurement of walking endurance and walking velocity with questionnaire: Validation of the walking impairment questionnaire in men and women with peripheral arterial disease ☆ ☆☆ ★

OBJECTIVES The Walking Impairment Questionnaire (WIQ) was designed to measure community walking ability in patients with peripheral arterial disease (PAD) and intermittent claudication. We compared the WIQ scores to objective measures of walking in a heterogeneous group of patients with and without PAD. METHODS The study was designed as a cross-sectional study, with the setting in an academic medical center. The subjects were patients with PAD (n = 145) who were identified from a noninvasive vascular laboratory at an academic medical center. The patients without PAD (n = 65) were identified from a general medicine practice. The average number of comorbidities was 2.03 for patients with PAD and 1.52 for patients without PAD. Among the patients with PAD, 28% had classical intermittent claudication symptoms and 55% had exertional leg symptoms other than claudication. The main outcome measures were the WIQ estimates of the patient-reported walking distance and walking speed on a scale of 0 to 100. Walking endurance was measured objectively with the 6-minute walk. Walking velocity was measured with a 4-m walk. PAD and PAD severity were defined with the ankle brachial index. RESULTS The Spearman rank correlation coefficients (rho) between the WIQ distance score and the 6-minute walk score were 0.557 among patients with PAD (P <.001) and 0.484 among patients without PAD (P <.001). The correlation coefficients between the WIQ speed score and the usual-paced 4-m walk score were 0.528 among patients with PAD (P <.001) and 0.524 among patients without PAD (P <.001). The correlations were not affected by the presence versus the absence of intermittent claudication, by PAD severity, or by the presence of 2 or more versus less than 2 comorbid illnesses. The WIQ scores in the highest and lowest quartiles were the most closely associated with the objective measures of function. CONCLUSION The WIQ is a valid measure of community walking ability in a heterogeneous group of patients with and without PAD. The WIQ discriminates best among patients in the highest and the lowest quartiles of walking speed and endurance.

Prevalence and Significance of Unrecognized Lower Extremity Peripheral Arterial Disease in General Medicine Practice

OBJECTIVE: To determine the prevalence of unrecognized lower extremity peripheral arterial disease (PAD) among men and women aged 55 years and older in a general internal medicine (GIM) practice and to identify characteristics and functional performance associated with unrecognized PAD.DESIGN: Cross-sectional.SETTING: Academic medical center.PARTICIPANTS: We identified 143 patients with known PAD from the noninvasive vascular laboratory, and 239 men and women aged 55 years and older with no prior PAD history from a GIM practice. Group 1 consisted of patients with PAD consecutively identified from the noninvasive vascular laboratory (n=143). Group 2 included GIM practice patients found to have an ankle brachial index less than 0.90, consistent with PAD (n=34). Group 3 consisted of GIM practice patients without PAD (n=205).MEASUREMENTS AND MAIN RESULTS: Leg functioning was assessed with the 6-minute walk, 4-meter walking velocity, and Walking Impairment Questionnaire (WIQ). Of GIM practice patients, 14% had unrecognized PAD. Only 44% of patients in Group 2 had exertional leg symptoms. Distances achieved in the 6-minute walk were 1,130, 1,362, and 1,539 feet for Groups 1, 2, and 3, respectively, adjusting for age, gender, and race (P<.001). The degree of difficulty walking due to leg symptoms as reported on the WIQ was comparable between Groups 2 and 3 and significantly greater in Group 1 than Group 2. In multiple logistic regression analysis including Groups 2 and 3, current cigarette smoking was independently associated with unrecognized PAD (odds ratio [OR], 6.82; 95% confidence interval [95% CI], 1.55 to 29.93). Aspirin therapy was nearly independently associated with absence of PAD (OR, 0.37; 95% CI, 0.12 to 1.12).CONCLUSION: Unrecognized PAD is common among men and women aged 55 years and older in GIM practice and is associated with impaired lower extremity functioning. Ankle brachial index screening may be necessary to diagnose unrecognized PAD in a GIM practice.

Physical performance in peripheral arterial disease : A slower rate of decline in patients who walk more

Context Patients with lower-extremity peripheral arterial disease (PAD) benefit from supervised walking programs, but cost, travel, and other factors often limit participation. Contribution This prospective study shows that a self-directed program of walking at least 3 times per week for exercise is associated with a significantly reduced functional decline during the subsequent year in patients with PAD when compared with those who walk less frequently. Implications Self-directed walking for exercise may benefit a much larger proportion of patients with PAD than is currently being served by supervised rehabilitation programs. Cautions Observational studies, such as this one, cannot prove a causal relationship between walking frequency and functional decline. The Editors Peripheral arterial disease (PAD) of the lower extremities affects 20% to 30% of older patients in general medical practices (1, 2). Most patients with the disease do not have classical symptoms of intermittent claudication (1-3). Compared with those without PAD, persons with the disease have significantly greater functional impairment and more rapid functional decline (2-4). Exercise rehabilitation that includes supervised treadmill walking substantially improves treadmill walking performance in men and women with intermittent claudication (5). However, such barriers as cost, transportation, and program availability often limit access to exercise rehabilitation programs for patients with PAD (6, 7). Clinical guidelines for PAD recommend supervised walking exercise, but evidence for the benefits of unsupervised walking exercise is minimal to absent (8, 9). Specifically, it is unknown whether patients with PAD who engage in regular self-directed walking exercise have less functional decline than those who are sedentary. For persons with PAD, supervised treadmill walking exercise 3 or more times per week is more effective than less frequent supervised walking exercise (5). Therefore, we conducted a prospective observational study to examine whether patients with PAD who report that they walk for exercise 3 or more times per week have less functional decline than PAD participants who walk for exercise less frequently. Methods Methods for this longitudinal observational study of men and women with and without PAD have been described elsewhere (4). The protocol was approved by the institutional review boards of Northwestern University and Catholic Health Partners Hospital. Participants gave informed consent. Participant Eligibility Participants were 55 years of age and older at baseline. Potential participants were identified consecutively from patients who tested positive for PAD in 3 Chicago-area noninvasive vascular laboratories. A few participants were identified from lists of consecutive patients with recent appointments in our general internal medicine practice. This latter group of patients was screened for PAD by calculating their anklebrachial index at baseline; PAD was defined as an index of less than 0.90 (10-12). Baseline visits occurred between October 1998 and January 2000, and follow-up visits were scheduled annually. Exclusion Criteria Exclusion criteria have been previously reported (4). Patients with dementia, recent major surgery, or foot or leg amputations were excluded. We also excluded nursing home residents and wheelchair-bound patients. Patients who did not speak English were excluded because the investigators were not fluent in non-English languages. Participants who underwent leg revascularization were excluded from analyses after the procedure. AnkleBrachial Index Measurement In accordance with established methods, we used a hand-held Doppler probe (Nicolet Vascular Pocket Dop II, Golden, Colorado) to obtain systolic pressures in the right and left brachial, dorsalis pedis, and posterior tibial arteries (4, 13, 14). To maximize precision, each pressure was measured twice. We calculated the anklebrachial index in each leg by dividing the mean of all 4 dorsalis pedis and posterior tibial pressures by the mean of the 4 brachial pressures (13). When calculated by this method, the index correlates more closely with lower-extremity arterial function than when determined by alternative methods (13). We used the average brachial pressures in the arm with highest pressure when the measurement was higher in the same arm in both measurement sets and the 2 brachial pressures differed by 10 mm Hg or more in at least 1 measurement set; in such cases, subclavian stenosis was possible (13, 14). The lowest anklebrachial index was used in analyses. Leg Symptoms On the basis of a previous study (3, 4, 15), we used the San Diego Claudication Questionnaire to classify patients into 5 groups according to type of leg symptoms. Four groups had exertional leg symptoms as determined by an affirmative response to the question, Do you get pain in either leg or buttock on walking? These participants were further classified as having 1) intermittent claudication (n= 133), defined as exertional calf pain that does not begin at rest, causes the participant to stop walking, and resolves within 10 minutes of rest; 2) leg pain on exertion and rest (n= 76), defined as exertional leg pain that sometimes begins at rest; 3) atypical exertional leg pain/carry on (n= 39), defined as exertional leg symptoms that do not begin at rest and do not stop the individual while walking; and 4) atypical exertional leg pain/stop (n= 89), defined as exertional leg symptoms that do not begin at rest, stop the individual from walking, and do not involve the calves or resolve within 10 minutes of rest. A fifth group of patients was defined as asymptomatic (n= 80) because they reported no pain in either leg or buttock on walking. Comorbid Conditions We used algorithms developed for the Womens Health and Aging Study to document the following comorbid conditions: angina, diabetes mellitus, myocardial infarction, stroke, heart failure, pulmonary disease, spinal stenosis, disk disease, Parkinson disease, and hip fracture (16). American College of Rheumatology criteria were used to diagnose knee and hip osteoarthritis (17, 18). Functional Measures Rationale for use of the specific functional outcome measures used in the Walking and Leg Circulation Study has been described previously (19). Timed Walk Per a standardized protocol (20, 21), participants walked up and down a 100-foot hallway for 6 minutes after they were instructed to cover as much distance as possible during the allotted time. Repeated Chair Rises Participants sat in a straight-backed chair with their arms folded across their chest and rose to a standing position, repeating the exercise 5 consecutive times as quickly as possible. We measured the time each patient required to complete 5 chair rises. Standing Balance Participants were asked to hold 3 increasingly difficult standing positions for 10 seconds each: standing with feet together and parallel (side-by-side stand); standing with feet parallel, with the toes of 1 foot adjacent to and touching the heel of the opposite foot (semi-tandem stand); and standing with 1 foot directly in front of the other (tandem stand) (22, 23). Walking Velocity Walking velocity was measured with a 4-meter walk performed at usual and fastest pace. For the usual-paced walk, participants were instructed to walk at their usual pace, as if going down the street to the store. For the fastest-paced walk, participants were instructed to walk as fast as they could. Each walk was demonstrated by the research assistant. Participants were given the command ready, go; timing began on go. Each walk was performed twice, and the faster time in each pair was used in analyses (22, 23). Summary Performance Score The summary performance score combined data from the usual-paced 4-meter walking velocity, time to rise from a seated position 5 times, and standing balance. Individuals received a score of 0 for each task they were unable to complete. Scores ranging from 1 to 4 were assigned for all completed tasks; the scoring system was based on quartiles of performance for over 5000 participants in the Established Populations for the Epidemiologic Study of the Elderly (22, 23). Scores were then summed to obtain the summary performance score, which ranged from 0 to 12. Exercise During each study visit, participants were classified as current exercisers if they responded affirmatively to the question, During the past 2 weeks, have you gone walking for exercise? Frequency and duration of walking for exercise were also determined at each visit. A minimum frequency of 3 times per week and a minimum duration of 30 minutes per session are most optimal for supervised walking exercise programs in patients with PAD according to published literature (5). Therefore, we defined optimal walking frequency as 3 or more times per week and optimal walking duration as 90 minutes per week. Depressive Symptoms We measured depressive symptoms annually by using the Geriatric Depression Scale (short form), a 15-item questionnaire (24). Possible scores for the questionnaire ranged from 0 to 15; a score of 0 indicated no depressive symptoms and a score of 15 indicated that all depressive symptoms defined in the questionnaire were present. Other Measures Height and weight were measured at each visit. Body mass index (BMI) was calculated by dividing the patients body weight in kilograms by the square of his or her height in meters. Patients annually reported cigarette use (pack-years) and the number of blocks they walked during the past week. The principal investigator reviewed all medication use to identify patients who used aspirin, statins, and angiotensin-converting enzyme inhibitors. Physical Activity We measured each patients physical activity continuously over 7 days (beginning with the baseline visit) by using the Caltrac (Muscle Dynamics Fitness Network, Torrance, California) vertical accelerometer (25-29). This accelerometer

Leg Symptoms, the Ankle‐Brachial Index, and Walking Ability in Patients With Peripheral Arterial Disease

AbstractOBJECTIVE: To determine how functional status and walking ability are related to both severity of lower extremity peripheral arterial disease (PAD) and PAD-related leg symptoms. DESIGN: Cross-sectional study. SETTING: Academic medical center. PARTICIPANTS: Patients aged 55 years and older diagnosed with PAD in a blood flow laboratory of general medicine practice (n=147). Randomly selected control patients without PAD were identified in a general medicine practice (n=67). MEASUREMENTS: Severity of PAD was measured with the ankle-brachial index (ABI). All patients were categorized according to whether they had (1) no exertional leg symptoms; (2) classic intermittent claudication; (3) exertional leg symptoms that also begin at rest (pain at rest), or (4) exertional leg symptoms other than intermittent claudication or pain at rest (atypical exertional leg symptoms). Participants completed the 36-Item Short-Form Health Survey (SF-36) and the Walking Impairment Questionnaire (WIQ). The WIQ quantifies patient-reported walking speed, walking distance, and stairclimbing ability, respectively, on a scale of 0 to 100 (100=best). MAIN RESULTS: In multivariate analyses patients with atypical exertional leg symptoms, intermittent claudication, and pain at rest, respectively, had progressively poorer scores for walking distance, walking speed, and stair climbing. The ABI was measurably and independently associated with walking distance (regression coefficient=2.87/0.1 ABI unit, p=.002) and walking speed (regression coefficient=2.09/0.1 ABI unit, p=.015) scores. Among PAD patients only, pain at rest was associated independently with all WIQ scores and six SF-36 domains, while ABI was an independent predictor of WIQ distance score. CONCLUSIONS: Both PAD-related leg symptoms and ABI predict patient-perceived walking ability in PAD.

Alcohol consumption among HIV-infected patients

This prospective, cohort study analyzed the prevalence of alcoholism and patterns of alcohol intake over time in a cohort of HIV-infected patients, predominantly homosexual/bisexual men. One hundred eleven HIV-positive subjects were recruited from a comprehensive HIV clinic associated with a large Midwestern university hospital. Each participant completed the Michigan Alcoholism Screening Test (MAST) survey and a standardized quantity—frequency questionnaire on alcohol intake at enrollment. The quantity—frequency scale was repeated every six months for a total of 30 months. Forty-five of the 111 subjects (41%) met the criteria for alcoholism, as defined by a MAST score 5 or higher. There was a significant decrease in alcohol consumption over time, from 6.4 drinks/week in the initial time period to 3.9 drinks/week by the final time period (p<0.001).

D-Dimer, Inflammatory Markers, and Lower Extremity Functioning in Patients With and Without Peripheral Arterial Disease

Background—We determined whether higher levels of D-dimer, C-reactive protein (CRP), fibrinogen, and serum amyloid A are associated independently with functional impairment in patients with and without peripheral arterial disease (PAD). Methods and Results—Participants were 370 men and women with PAD (ankle brachial index <0.90) and 231 without PAD. Functional outcomes were 6-minute walk distance and 4-meter walking velocity. A summary performance score combined performance in walking speed, standing balance, and time for 5 repeated chair rises into an ordinal score ranging from 0 to 12 (12=best). Adjusting for age, sex, ankle brachial index, comorbidities, and other potential mediators and confounders, D-dimer levels were associated independently and inversely with performance on all 3 functional measures in the entire cohort and among patients with and without PAD, respectively. Adjusting for known and potential confounders, CRP levels were associated independently with 6-minute walk distance and the summary performance score among participants with PAD. No significant associations were observed between CRP and the functional measures among participants without PAD. Fibrinogen and SAA levels were not associated independently with the functional measures. Conclusions—Higher D-dimer levels are associated with poorer functioning among individuals with and without PAD. Higher CRP levels were associated with poorer 6-minute walk performance and a lower summary performance score among participants with PAD but not among those without PAD. Additional study is needed to determine whether D-dimer and CRP are involved in the pathophysiology of functional impairment or whether they are simply sensitive markers of the extent of systemic atherosclerosis.

Measuring Physical Activity in Peripheral Arterial Disease: A Comparison of Two Physical Activity Questionnaires with an Accelerometer:

Peripheral arterial disease (PAD)-related exertional leg pain may limit physical activity, thereby contributing to mobility loss and increasing cardiovascular morbidity and mortality in men and women with PAD. The objectives of this study were: (1) to compare objectively measured physical activity levels between patients with and without PAD, (2) to assess the validity of two physical activity questionnaires in patients with PAD. Twenty PAD patients from a noninvasive vascular laboratory and 21 patients without PAD from a general medicine practice wore an accelerometer continuously for 7 days to measure physical activity objectively. After 7 days, participants completed the leisure time physical activity questionnaire (LTPAQ), derived from the Health Interview Survey, and the Stanford 7-day physical activity recall questionnaire (PARQ). PAD participants had markedly lower physical activity levels than non-PAD participants as measured by accelerometer (803 kcal/week ±364 (range=284-2,000, median=708) vs 1,750 kcal/week ±1,296 (range=882-6,586, median=1,278), p<0.001). For the LTPAQ, physical activity levels in PAD and non-PAD participants were 609 kcal/week ±576 (range=0-2,085, median=529) vs 832 kcal/week ±784 (range=53-2,820, median= 623), p=0.128. For the PARQ, physical activity levels in PAD and non-PAD participants were 234 METS/week ±21 (range=214-301, median=229) vs 238 METS/week ±11 (range=225-268, median=234), p=0.454, respectively. Pearsons correlation coefficient for the association between the accelerometer and the log-transformed LTPAQ measure was 0.419 (p=0.006). Pearsons correlation coefficient was 0.348 for the association between the accelerometer and the log-transformed PARQ measure of physical activity (p=0.026). In conclusion, PAD patients have significantly lower physical activity levels than non-PAD patients. Two commonly used physical activity questionnaires were less sensitive than objective measurement to the association between PAD and inactivity.

The ankle brachial index independently predicts walking velocity and walking endurance in peripheral arterial disease

OBJECTIVES: Maintaining function among older men and women is an important public health goal as the population lives longer with chronic disease. We report the relationships between lower extremity peripheral arterial disease (PAD), PAD severity, and PAD‐related symptoms with walking velocity and endurance among men and women aged 55 and older.

Gait alterations associated with walking impairment in people with peripheral arterial disease with and without intermittent claudication

OBJECTIVES: To describe gait alterations associated with impaired walking endurance in patients with and without lower‐extremity peripheral arterial disease (PAD) and determine whether the Caltrac accelerometer provides a valid measure of physical activity in PAD.

Functional status and walking ability after lower extremity bypass grafting or angioplasty for intermittent claudication: results from a prospective outcomes study.

OBJECTIVE The purpose of this study was the prospective comparison of functional outcomes after lower extremity bypass grafting surgery, angioplasty, or medical management of intermittent claudication. METHODS The study was designed as a prospective cohort study to compare functional outcomes for patients with interventional management to medical management, including a matched (younger, with more disability) subgroup, followed for a mean of 19 months. Sixteen Chicago-area vascular surgery clinics participated in the study. The subjects were consecutively enrolled patients with an abnormal ankle-brachial blood pressure index (ABI), without signs of rest pain, ulcer, or gangrene, and without prior lower extremity revascularization procedures. The main outcome measures were changes in physical functioning, community walking distance, bodily pain, leg symptoms, and ABI. RESULTS Of the 526 study patients, 20% underwent revascularization procedures (60 surgical bypass grafting and 44 angioplasty only). The mean ABI improved significantly for the patients who underwent bypass grafting surgery (0.20; P <.001) and modestly for the patients who underwent angioplasty (0.09; P <. 05). Patients undergoing bypass grafting and angioplasty maintained highly significant (P <.001) improvements in mean physical functioning, (17%, 14%), bodily pain (18%, 13%), and walking distance (28%, 27%) scores and reported greater leg symptom improvement. The results were far superior for the patients with greater improvement in ABI. The conditions of the 277 unmatched patients who underwent medical management declined on all outcome measures, and the conditions of the 145 matched patients who underwent medical management improved 5% (P <.001) on walking distance score. Eighteen percent of the study patients failed to complete the full study follow-up period. CONCLUSION Most of the functional improvement achieved by patients who underwent interventional management appears to be related to improved patency rather than to selection bias or placebo effects. The functional gains were approximately half those often reported for patients for hip arthroplasty and similar to patients who undergo elective coronary angioplasty.