Background: Consumer-based wearables are becoming more popular and provide opportunities to track individual’s clinical parameters remotely. However, literature about their criterion and known-groups validity is scarce. Objective: This study aimed to assess the validity of the Fitbit Charge 4, a wrist-worn consumer-based wearable, to measure clinical parameters (ie, daily step count, resting heart rate [RHR], heart rate variability [HRV], respiratory rate [RR], and oxygen saturation) in patients with chronic obstructive pulmonary disease (COPD) and healthy controls in free-living conditions in Belgium by comparing it with medical-grade devices. Methods: Participants wore the Fitbit Charge 4 along with three medical-grade devices: (1) Dynaport MoveMonitor for 7 days, retrieving daily step count; (2) Polar H10 for 5 days, retrieving RHR, HRV, and RR; and (3) Nonin WristOX ₂ 3150 for 4 nights, retrieving oxygen saturation. Criterion validity was assessed by investigating the agreement between day-by-day measures of the Fitbit Charge 4 and the corresponding reference devices. Known-groups validity was assessed by comparing patients with COPD and healthy controls. Results: Data of 30 patients with COPD and 25 age- and gender-matched healthy controls resulted in good agreement between the Fitbit Charge 4 and the corresponding reference device for measuring daily step count (intraclass correlation coefficient [ICC _2,1 ]=0.79 and ICC _2,1 =0.85, respectively), RHR (ICC _2,1 =0.80 and ICC _2,1 =0.79, respectively), and RR (ICC _2,1 =0.84 and ICC _2,1 =0.77, respectively). The agreement for HRV was moderate (healthy controls: ICC _2,1 =0.69) to strong (COPD: ICC _2,1 =0.87). The agreement in measuring oxygen saturation in patients with COPD was poor (ICC _2,1 =0.32). The Fitbit device overestimated the daily step count and underestimated HRV in both groups. While RHR and RR were overestimated in healthy controls, no difference was observed in patients with COPD. Oxygen saturation was overestimated in patients with COPD. The Fitbit Charge 4 detected significant differences in daily step count, RHR, and RR between patients with COPD and healthy controls, similar to those identified by the reference devices, supporting known-groups validity. Conclusions: Although the Fitbit Charge 4 shows mainly moderate to good agreement, measures of clinical parameters deviated from the reference devices, indicating that monitoring patients remotely and interpreting parameters requires caution. Differences in clinical parameters between patients with COPD and healthy controls that were measured by the reference devices were all detected by the Fitbit Charge 4.

Background: While patients with COPD often cite weather conditions as a reason for inactivity, little is known about the relationship between physical activity (PA) and weather conditions. The present study investigated the association of day-to-day weather changes on PA in patients with COPD and investigated patient characteristics related to being more or less influenced by weather conditions.Methods: In this longitudinal analysis, device-based day-by-day step counts were objectively measured in COPD patients for up to 12 months. Daily meteorological data (temperature, precipitation, wind speed, hours of sunlight and daylight) were linked to the daily step count and individual and multivariable relationships were investigated using mixed-model effects. Individual R²was calculated for every subject to investigate the estimated influence of weather conditions on a patient level and its relationship with patient characteristics.Results: We included 50 patients with a mean±sdfollow-up time of 282±93 days, totalling 14 117 patient-days. Daily temperature showed a positive linear pattern up until an inflexion point, after which a negative association with increasing temperature was observed (p<0.0001). Sunshine and daylight time had a positive association with PA (p<0.0001). Precipitation and wind speed were negatively associated with PA (p<0.0001). The median per-patient R²for overall weather conditions was 0.08, ranging from 0.00 to 0.42. No strong associations between patient characteristics and per-patient R²were observed.Conclusion: Weather conditions are partly associated with PA in patients with COPD, yet the overall explained variance of PA due to weather conditions is rather low and varied strongly between individuals.

Background: Immediately after discharge from hospital, COVID-19 patients have poor physical function and impaired performance in activities of daily living. Persisting symptoms and cognitive impairments have been reported, but the long-term impact on objectively measured physical activity (PA) in patients hospitalized for COVID-19 is not clear. Methods: A prospective cohort study was conducted to compare objectively measured PA and physical function 12 months post discharge in patients who were hospitalized for COVID-19 with age- and sex-matched healthy controls and to elucidate the impact of ICU admission on these outcomes. PA was objectively assessed using accelerometry in patients, healthy controls, and in a subset of partners of patients. Additionally, lung function, physical function (six-minute walk distance (6 MWD) and isometric quadriceps and handgrip force), symptom experience, and health-related quality of life (HRQoL) were evaluated in patients with and without ICU admission. Results: Included in the study were 101 patients (60 ± 10 years, 69% male), 36 healthy controls (60 ± 9 years, 58% male), and 14 partners (55 ± 8 years, 21% male). Daily step count and movement intensity (MI) during walking in patients were significantly lower compared with healthy controls (6726 ± 328 vs. 8155 ± 555 n.day⁻¹, p = 0.03 and 1.99 ± 0.04 vs. 2.21 ± 0.07 min/s².day⁻¹, p = 0.005). PA levels of patients and their partners were comparable. Physical function, symptom experience, HRQoL, and PA levels were comparable in patients with and without ICU admission (p > 0.05). Daily step count was weakly positively associated with 6 MWD (r = 0.30). Conclusions: One year post discharge, patients had lower PA levels than healthy controls. ICU admission did not affect physical function, symptoms, HRQoL or activity levels.

Background: Patients with early-stage (I–IIIA) resectable non-small cell lung cancer (NSCLC) often experience reduced physical activity (PA) after surgery. PA telecoaching may support a more active lifestyle, but evidence in this population is limited. Objective: To evaluate acceptability, feasibility, safety, and actual usage of an automated and manual PA telecoaching program following surgery for NSCLC. Methods: In this multicenter, single-blind study, patients received either an eight-week automated coaching program (ACP) with a customized smartphone app or a manual coaching program (MCP) with weekly phone calls from a coach. Both groups used an activity tracker, linked to their smartphone, to monitor steps and receive feedback. Primary outcomes included acceptability, feasibility, safety and usage, assessed via questionnaires and interviews. Secondary outcomes included objectively measured PA (accelerometry), functional exercise capacity (six-minute walk distance) and symptoms (dyspnea, fatigue) and quality of life, evaluated via questionnaires. Results: Nineteen patients (12 males; 68 ± 6 years; baseline daily steps 7820 ± 2799) were included. The majority (18/19) found the intervention enjoyable, and a minority (6/19) reported minor smartphone issues. All patients wore the activity tracker consistently. No adverse events occurred. The ACP required significantly less coach contact time compared to the MCP (25 ± 14 vs. 54 ± 15 min, p = 0.0003). No other differences in primary outcomes were observed between groups. Changes in secondary outcomes were limited in both groups. Conclusion: PA telecoaching is feasible, well accepted, and safe in patients with NSCLC post-surgery, with excellent activity tracker adherence. The ACP required less coach involvement. However, increasing PA remains challenging, and no conclusions can be made about the effectiveness of telecoaching. Future research should explore longer interventions in larger populations to assess efficacy and long-term outcomes.

Starting rehabilitation soon after an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is crucial to diminish the detrimental effects of this acute event on muscle function. However, uptake in outpatient pulmonary rehabilitation is low. To design and test a feasible, acceptable and accessible exercise training program (ETP) in primary care for patients experiencing an AECOPD. (1) A literature review and qualitative study to develop an ETP and (2) A feasibility study of the ETP implemented in primary care. (1) The development of the ETP proceeded in several phases with input from different stakeholders through focus group discussions. (2) Patients experiencing a moderate or severe AECOPD were included and followed the ETP for two weeks with a physiotherapist in primary care. Interviews with the participants took place and patients were given the choice to complete the eight-week program. (1) Six discussion sessions took place. The ETP contained a flexible set of progressively more difficult exercises applicable in a primary care practice. (2) Eight patients experiencing a moderate (n = 1) or severe (n = 7) AECOPD were included. Patients started the first physiotherapy session 5 (2-6) days after the start of their symptoms or hospital discharge. Seven patients wanted to complete the ETP. An ETP in primary care is feasible, acceptable and accessible for patients experiencing a moderate or severe AECOPD, and for physiotherapists. The effectiveness of this ETP on muscle function and physical activity is currently under investigation in a RCT. CONTRIBUTION OF THE PAPER.