Hsieh P-L1,2, Chien M-Y1,3,4, Wu H-D5, Chien J-Y6, Yang P-Y2, Lin J-S1, Lee C-T1, Wang L-Y1,2
1National Taiwan University, School and Graduate Institute of Physical Therapy, College of Medicine, Taipei, Taiwan, 2National Taiwan University Hospital, Physical Therapy Center, Taipei, Taiwan, 3National Taiwan University Hospital, Division of Physical Therapy, Department of Physical Medicine and Rehabilitation, Taipei, Taiwan, 4National Taiwan University Hospital, Center for Obesity, Lifestyle and Metabolic Surgery, Taipei, Taiwan, 5National Taiwan University Hospital, Department of Integrated Diagnostic and Therapeutics, Taipei, Taiwan, 6National Taiwan University Hospital, Department of Internal Medicine, Taipei, Taiwan
Background: Exercise training improves dyspnea and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). However, the magnitude of functional exercise capacity (FEC) improvement in response to exercise training differed substantially among published studies.
Purpose: To explore and compare differences of FEC in response to exercise training in patients with COPD grouped using trajectory modeling.
Methods: A total of 71 patients with COPD from the outpatient department of a university hospital were included. All participants underwent structured exercise training for 8 weeks which consisted of aerobic and resistance training. FEC was assessed by six-minute walk test (6MWT) at baseline, 4-wk, 8-wk, and monthly for two months after the completion of training. Parameters measured were six-minute walk distance (6MWD) and physiological responses during 6MWT. Lower extremity strength was measured by one-repetition maximum leg press. Group-based trajectory modeling was used to explore the patterns of 6MWD in response to exercise training. Generalized estimating equation methods were then used to detect the differences within and between trajectory groups across time. Significance level was set at α = 0.05.
Results: Participants were grouped into “low” (n = 14), “moderate” (n = 41), and “high” (n = 16) FEC group. Mean age and body mass index were similar among groups. The proportion of moderate to severe COPD in low, moderate, and high FEC group was 50%, 41%, and 19%, respectively. Oxygen supplementation was required during exercise training for 57%, 29%, and 6% in low, moderate, and high FEC group, respectively. Baseline leg press was significantly higher in high FEC group compared to other two groups. Compared to baseline, 6MWD improved significantly after 4-wk of training in all groups (all p 0.05) but only high FEC group demonstrated further increases at 8-wk of training. Only moderate FEC group showed further increases of 6MWD during follow-ups; in contrast, low FEC group showed a declining trend through follow-ups. Compared to baseline, maximal leg-press strength increased significantly after training in all groups and were maintained for the following two months.
Conclusion(s): Patients with COPD showed distinct patterns of 6MWD changes in response to exercise training. Factors for low FEC in patients with COPD included poor lower-extremity strength, supplemental oxygen requirement and disease severity.
Implications: Influencing factors associated with FEC improvement in response to exercise training for patients with COPD warrants further investigations.
Keywords: Chronic obstructive pulmonary disease, Functional exercise capacity, Trajectory
Funding acknowledgements: No specific financial support was obtained for this study.
Purpose: To explore and compare differences of FEC in response to exercise training in patients with COPD grouped using trajectory modeling.
Methods: A total of 71 patients with COPD from the outpatient department of a university hospital were included. All participants underwent structured exercise training for 8 weeks which consisted of aerobic and resistance training. FEC was assessed by six-minute walk test (6MWT) at baseline, 4-wk, 8-wk, and monthly for two months after the completion of training. Parameters measured were six-minute walk distance (6MWD) and physiological responses during 6MWT. Lower extremity strength was measured by one-repetition maximum leg press. Group-based trajectory modeling was used to explore the patterns of 6MWD in response to exercise training. Generalized estimating equation methods were then used to detect the differences within and between trajectory groups across time. Significance level was set at α = 0.05.
Results: Participants were grouped into “low” (n = 14), “moderate” (n = 41), and “high” (n = 16) FEC group. Mean age and body mass index were similar among groups. The proportion of moderate to severe COPD in low, moderate, and high FEC group was 50%, 41%, and 19%, respectively. Oxygen supplementation was required during exercise training for 57%, 29%, and 6% in low, moderate, and high FEC group, respectively. Baseline leg press was significantly higher in high FEC group compared to other two groups. Compared to baseline, 6MWD improved significantly after 4-wk of training in all groups (all p 0.05) but only high FEC group demonstrated further increases at 8-wk of training. Only moderate FEC group showed further increases of 6MWD during follow-ups; in contrast, low FEC group showed a declining trend through follow-ups. Compared to baseline, maximal leg-press strength increased significantly after training in all groups and were maintained for the following two months.
Conclusion(s): Patients with COPD showed distinct patterns of 6MWD changes in response to exercise training. Factors for low FEC in patients with COPD included poor lower-extremity strength, supplemental oxygen requirement and disease severity.
Implications: Influencing factors associated with FEC improvement in response to exercise training for patients with COPD warrants further investigations.
Keywords: Chronic obstructive pulmonary disease, Functional exercise capacity, Trajectory
Funding acknowledgements: No specific financial support was obtained for this study.
Topic: Cardiorespiratory
Ethics approval required: Yes
Institution: National Taiwan University Hospital
Ethics committee: National Taiwan University Hospital Research Ethics Committee
Ethics number: 201805017RINB
All authors, affiliations and abstracts have been published as submitted.
