A home-based strength training program does not improve dyspnea in patients with chronic obstructive lung disease (COPD), but it does improve some functional capacity and helps patients feel better, a 12-month long, HOMEX exercise program shows.
"Home-based programs became increasingly popular in the last years and complement traditional center-based inpatient and outpatient PR (pulmonary rehabilitation)," Anja Frei, PhD, University of Zurich, Zurich, Switzerland, and colleagues reported.
"Our study showed that the HOMEX strength training program had no effect on dyspnea after 12 months in persons with COPD who completed PR, [but] the program improved functional exercise capacity…and many participants reported having perceived positive effects that they attributed to the training," investigators add.
The study was published online August 8 in the journal CHEST.
Intervention or Controls
A total of 123 patients (mean age, 67 years) with COPD were randomly assigned to the intervention group or to the control group. The mean forced expiratory volume in 1 second (FEV1) was 39.3% of predicted. Three quarters of participants had severe or very severe COPD.
A total of 104 patients completed the 12-month study. "The primary outcome was change in dyspnea (Chronic Respiratory Questionnaire, CRQ) from baseline to 12 months," investigators note. Secondary outcomes included change in exercise capacity as assessed by the 1-minute-sit-to-stand test (1-min-STST); the 6-minute walk test (6MWT); health-related quality of life, exacerbations, and symptoms.
The HOMEX program was a structured, home-based strength training program developed for patients with COPD that could be done following the pulmonary rehabilitation program, with the intention of maintaining the training benefits gained during pulmonary rehabilitation.
"We deliberately focused on the strength component of exercise training due to the fact that skeletal muscle dysfunction is prevalent in COPD and [is] associated with lower daily physical activity and poor prognosis," the authors explain. Patients had completed pulmonary rehabilitation no longer than 1 month prior to starting the training program. The program required a chair and a set of resistance bands and consisted of trunk, upper limb, and lower limb exercises done at different intensity levels.
Participants were instructed to do the exercises 6 days per week for about 20 minutes per day over the 12-month study interval. The dyspnea score dropped from 4.65 to 4.42 from baseline to 12 months in the intervention group compared with a drop from 4.61 to 4.06 in the control group, the investigators reported. "There was no evidence for a difference between the two groups in change in the 6MWT distance after 12 months…but moderate evidence for a between-group difference in the change of repetitions in the 1-min-STST favoring the IG (intervention group)," they also noted, at an adjusted mean difference of 2.6 (95% CI, 0.22 - 5.03, P = .033).
In all other outcomes, no differences were observed between the two groups. Importantly, 70% of participants carried on with the HOMEX training program until study endpoint and at least 79% of them persevered for at least 10 months. Based on results from a satisfaction survey, 81% of participants randomly assigned to the intervention group indicated that they "liked" or "very much liked" participating in the program, and 79% of them reported that they experienced positive effects that they felt were attributed to the training.
"The program was safe and the majority of the multimorbid and severely ill study participants adhered to the training during the study year," the authors write. And while the program had no effect on functional exercise capacity as measured by the 6MWT, it did improve the strength and intramuscular coordination of the lower leg muscles because the program had repetitive sit-to-stand exercises as a component of the training. "Adherence to this long-term training program was surprisingly high," the authors say. "It was well accepted by COPD patients and may facilitate continued training at home.
One limitation of the study was that some participants did not travel to the rehabilitation clinic for a follow-up assessment.
The authors reported no relevant financial relationships.
CHEST. Published online August 8, 2022. Abstract