Real-world walking cadence in people with COPD

Abstract

IntroductionThe clinical validity of real-world walking cadence in people with chronic obstructive pulmonary disease (COPD) is unsettled. Objective: to assess the levels, variability and association with clinically relevant COPD characteristics and outcomes of real-world walking cadence.MethodsWe assessed walking cadence (steps per minute during walking bouts >10 s) from 7-days accelerometer data in 593 individuals with COPD from five European countries, and clinical and functional characteristics from validated questionnaires and standardised tests. Severe exacerbations during 12-months follow-up were recorded from patient reports and medical registries.ResultsParticipants were mostly male (80%) and had mean (sd) age 68 (8) years, post-bronchodilator FEV157 (19)%, and 6880 (3926) steps/day. Mean walking cadence was 88 steps/min, followed a normal distribution (sd=9), and was highly stable within-person (ICC 0.92 (95%CI 0.90–0.93)). After adjusting for age, sex, height and number of walking bouts in fractional polynomial or linear regressions, walking cadence was positively associated with FEV1,6-min walk distance, physical activity (steps/day, time in moderate-to-vigorous physical activity, vector magnitude units, walking time, intensity during locomotion), physical activity experience and health-related quality of life; and negatively associated with breathlessness and depression (all p<0.05). These associations remained after further adjustment for daily steps. In negative binomial regression adjusted for multiple confounders, walking cadence related to lower number of severe exacerbations during follow-up (IRR 0.94 per step/min, 95%CI 0.91–0.99, p=0.009).ConclusionsHigher real-world walking cadence is associated with better COPD status and lower severe exacerbations risk, which makes it attractive as future prognostic marker and clinical outcome.