Reasons persons with COPD do not walk and relationship with daily step count.

BACKGROUND: Physical activity (PA) is significantly reduced in persons with COPD. Assessing reasons why persons with COPD do not engage in PA can guide development of effective interventions to promote PA. METHODS: We queried 102 participants with stable COPD about disease-related and general reasons why they do not walk more. The StepWatch Activity Monitor (Orthocare Innovations, Mountlake Terrace, WA, USA) assessed daily step count, a direct measure of PA. Regression models assessed daily step count by response categories, adjusting for age and FEV1 % predicted. RESULTS: Subjects had mean age 72 ± 8 years and mean FEV1 1.48 ± 0.55 L (52 ± 19% predicted). COPD-related worries of becoming short of breath (SOB), needing to use inhalers, or oxygen level becoming low were endorsed by 31, 14, and 12 subjects, respectively. Controlling for age and FEV1% predicted, those who worried about becoming SOB walked an average of 1,329 fewer steps per day than those who did not worry (p = 0.020). Those who worried about needing to use inhalers walked an average of 1,806 fewer steps per day than those who did not worry (p = 0.016). Subjects who were the most motivated and confident walked significantly more than those who were the least motivated and confident. CONCLUSIONS: Presence of COPD-related reasons and lower motivation and confidence are associated with lower daily step count. Management of dyspnea and education about medication use during exercise, and strategies to increase motivation and confidence could facilitate walking in COPD.

Daily step count is associated with plasma C-reactive protein and IL-6 in a US cohort with COPD.

BACKGROUND: Physical activity is an important clinical marker of disease status in COPD. COPD is also characterized by low-grade systemic inflammation. However, the relationship between physical activity and systemic inflammation in COPD is unclear. METHODS: We monitored daily step count, a directly measured physical activity, using the StepWatch Activity Monitor, an ankle-worn accelerometer, in 171 people with stable COPD. Exercise capacity was assessed with the 6-min walk test (6MWT). We measured plasma C-reactive protein (CRP) and IL-6 levels. Linear regression models examined the cross-sectional associations of daily step count and 6MWT distance with CRP and IL-6 levels. RESULTS: Subjects had a mean age 72±8 years and mean FEV1 1.5±0.57 L (54±20% predicted). Median daily step count was 5,203 (interquartile range [IQR], 3,627-7,024], CRP level was 2.4 mg/L (IQR, 1.2-5.0), and IL-6 level was 2.9 pg/mL (IQR, 2.0-5.1). Each 1,000-step increase in daily step count was associated with a 0.94 mg/L and 0.96 pg/mL decrease in CRP (P=.020) and IL-6 (P=.044) levels, respectively, adjusting for age, FEV1 % predicted, pack-years smoked, cardiac disease, current statin use, history of acute exacerbations, and season. There was a significant linear trend of increasing daily step count by quartiles and decreasing CRP (P=.0007) and IL-6 (P=.023) levels. Higher 6MWT distance was also significantly associated with lower CRP and IL-6 values. CONCLUSION: People with COPD who walked the most had the lowest plasma CRP and IL-6 levels. These results provide the conceptual basis to study whether an intervention to promote walking will reduce systemic inflammation in people with COPD.

Daily step count predicts acute exacerbations in a US cohort with COPD.

BACKGROUND: COPD is characterized by variability in exercise capacity and physical activity (PA), and acute exacerbations (AEs). Little is known about the relationship between daily step count, a direct measure of PA, and the risk of AEs, including hospitalizations. METHODS: In an observational cohort study of 169 persons with COPD, we directly assessed PA with the StepWatch Activity Monitor, an ankle-worn accelerometer that measures daily step count. We also assessed exercise capacity with the 6-minute walk test (6MWT) and patient-reported PA with the St. George's Respiratory Questionnaire Activity Score (SGRQ-AS). AEs and COPD-related hospitalizations were assessed and validated prospectively over a median of 16 months. RESULTS: Mean daily step count was 5804±3141 steps. Over 209 person-years of observation, there were 263 AEs (incidence rate 1.3±1.6 per person-year) and 116 COPD-related hospitalizations (incidence rate 0.56±1.09 per person-year). Adjusting for FEV1 % predicted and prednisone use for AE in previous year, for each 1000 fewer steps per day walked at baseline, there was an increased rate of AEs (rate ratio 1.07; 95%CI = 1.003-1.15) and COPD-related hospitalizations (rate ratio 1.24; 95%CI = 1.08-1.42). There was a significant linear trend of decreasing daily step count by quartiles and increasing rate ratios for AEs (P = 0.008) and COPD-related hospitalizations (P = 0.003). Each 30-meter decrease in 6MWT distance was associated with an increased rate ratio of 1.07 (95%CI = 1.01-1.14) for AEs and 1.18 (95%CI = 1.07-1.30) for COPD-related hospitalizations. Worsening of SGRQ-AS by 4 points was associated with an increased rate ratio of 1.05 (95%CI = 1.01-1.09) for AEs and 1.10 (95%CI = 1.02-1.17) for COPD-related hospitalizations. CONCLUSIONS: Lower daily step count, lower 6MWT distance, and worse SGRQ-AS predict future AEs and COPD-related hospitalizations, independent of pulmonary function and previous AE history. These results support the importance of assessing PA in patients with COPD, and provide the rationale to promote PA as part of exacerbation-prevention strategies.

Daily step counts in a US cohort with COPD.

BACKGROUND: Baseline values for daily step counts in US adults with COPD and knowledge of its accurate measurement, natural change over time, and independent relationships with measures of COPD severity are limited. METHODS: 127 persons with stable COPD wore the StepWatch Activity Monitor (SAM) for 14 days, and 102 of them wore it a median 3.9 months later. SAM counts were compared to manual counts in the clinic. We assessed change over time, the effect of season, and relationships with forced expiratory volume in 1 s (FEV(1)) % predicted, 6-min walk test (6MWT) distance, the modified Medical Research Council (MMRC) dyspnea score, and the St. George's Respiratory Questionnaire Total Score (SGRQ-TS). RESULTS: 98% of subjects were males, with mean age 71 ± 8 years and FEV(1) 1.48 ± 0.54 L (52 ± 19% predicted). All 4 GOLD stages were represented, with the most subjects in GOLD II (44%) and GOLD III (37%). The SAM had >90% accuracy in 99% of subjects. Average step count was 5680 steps/day, which decreased with increasing GOLD stage (p = 0.0046). Subjects walked 645 fewer steps/day at follow-up, which was partly explained by season of monitoring (p = 0.013). In a multivariate model, FEV(1) % predicted, 6MWT distance and MMRC score were weakly associated with daily step counts, while SGRQ-TS was not. CONCLUSIONS: These findings will aid the design of future studies using daily step counts in COPD. Accurately measured, daily step counts decline over time partly due to season and capture unique information about COPD status.

A pilot study of an Internet walking program and pedometer in COPD.

BACKGROUND: Higher levels of physical activity are associated with better functional status, fewer hospital admissions, and lower mortality. In this pilot study, we examined the feasibility and safety of a novel program that combines a pedometer with a website to increase walking. METHODS: 27 persons with stable COPD wore the Omron HJ-720ITC pedometer and used the website for 90 days. They uploaded step-count data to the study server using their home computer and received an email each week with their individualized step-count goal. The website provided step-count feedback, education, and motivational content. Subjects participated in a monthly semi-structured interview by telephone. Subjects reported changes in medical condition by telephone or on the website. Paired T-tests assessed change in daily step counts. RESULTS: Subjects were males, mean age 72 ± 8 years, with moderate COPD, FEV(1) 1.57 ± 0.48 L (55 ± 16% predicted). 87% and 65% reported no problems using the pedometer and website, respectively. At month 3, 96% reported it was true that they knew their step count goal every day, and 52% reported that they were able to reach their goal. 95% of participants said they would recommend the walking program to another person with COPD. Eight subjects experienced breathing problems unrelated to the intervention. In 24 subjects with step counts at baseline and month 3, there was a significant increase of 1263 steps per day (approximately 1.0 km), p = 0.0054. CONCLUSIONS: The use of a website and pedometer was feasible and safe, and persons increased their daily walking.