Physical activity in patients with COPD: a reference frame based on functional capacity

Rationale: Physical activity (PA) management is a recommended treatment goal for patients with COPD, across the disease severity. We hypothesize that a reference frame based on functional capacity can guide patient selection for PA coaching interventions and will help to provide achievable PA goals to individual patients. Methods: A total of 213 patients with COPD (67% male, age 65 (8) year, BMI 26 (6) kg.m-2, FEV1 54 (20) %pred) were included in the present analysis, resulting in a total of 1460 valid days with objectively measured PA. We chose step count as primary outcome and categorized patients based on their 6MWD (bin per 100m). The 5th, 25th, 50th, 75th and 95th percentiles of daily step count were calculated. Next, because severity of the airflow obstruction was independently associated to PA, analyses were stratified for GOLD stage (I-II and III-IV). Results: The reference frame of PA is presented in Figure 1. As hypothesized, the PA one can expect of a patient with COPD is depending on the individual functional capacity. PA was slightly higher in patients in GOLD I-II for a given capacity, as compared to those in GOLD III-IV. Conclusion: The present data provide a reference frame for physical activity based on functional capacity. This framework can guide treatment selection and goals for physical activity coaching.