Physical activity monitoring in patients with peripheral arterial occlusive disease

Purpose. Physical activity is an important variable to measure in patients with peripheral arterial occlusive disease (PAOD) because of its relationship to cardiovascular disease morbidity and mortality. The purposes of this study were to (1) determine the reliability of measures of daily physical activity in PAOD participants using an accelerometer and a pedometer; and (2) assess the validity of both instruments by comparing them against validated physical activity questionnaires. Methods. Forty three patients with PAOD with a resting ankle/brachial index of 0.63 ± 0.19 were monitored for 2 consecutive weekdays with an accelerometer and pedometer worn on each hip. The 48-hour monitoring period was repeated approximately 1 week later. Results. The daily physical activity values obtained from the accelerometer were similar between the two testing periods, 352 ± 248 kcal/day vs. 337 ± 199 kcal/day; P = 0.61, with a reliability coefficient of r = 0.84. The steps obtained from the pedometer during each 2-day period also were similar, 4615 ± 2839 steps/day vs. 4498 ± 2768 steps/day; P = 0.75, with a reliability coefficient of r = 0.86. The physical activity values from the accelerometer moderately correlated with the Minnesota Leisure Time Physical Activity Questionnaire, r = 0.33; P < 0.01, and the NASA/Johnson Space Center Physical Activity Scale, r = 0.44; P < 0.001. Similarly, the relationship between the steps obtained from the pedometer and physical activity values from the Minnesota Leisure Time Physical Activity and NASA/Johnson Space Center Physical Activity Scale questionnaires were significant, r = 0.46 and r = 0.51; P < 0.001, respectively. Conclusion. These findings indicate that an accelerometer and pedometer are two instruments that reliably estimate the physical activity levels of patients with PAOD over 2 consecutive days. Furthermore, the activity monitors are moderately associated with validated physical activity questionnaires, suggesting that activity monitoring measures a different component of activities in patients with PAOD with intermit tent claudication.