Exacerbations in patients with chronic obstructive pulmonary disease receiving physical therapy: a cohort-nested randomised controlled trial

Abstract

Background: Physical exercise training aims at reducing disease-specific impairments and improving quality of life in patients with chronic obstructive pulmonary disease (COPD). COPD exacerbations in particular negatively impact COPD progression. Physical therapy intervention seems indicated to influence exacerbations and their consequences. However, information on the effect of physical therapy on exacerbation occurrence is scarce. This study aims to investigate the potential of a protocol-directed physical therapy programme as a means to prevent or postpone exacerbations, to shorten the duration or to decrease the severity of exacerbations in patients with COPD who have recently experienced an exacerbation. Besides, this study focuses on the effect of protocol-directed physical therapy on health status and quality of life and on cost-effectiveness and cost-utility in patients with COPD who have recently experienced an exacerbation.

Methods/design: A prospective cohort of 300 COPD patients in all GOLD stages will be constructed. Patients will receive usual multidisciplinary COPD care including guideline-directed physical therapy. Patients in this cohort who have GOLD stage 2 to 4 (post-bronchodilator FEV1/FVC < 0.7 and FEV1 < 80% of predicted), who receive reimbursement by health insurance companies for physical therapy (post-bronchodilator Tiffeneau-index < 0.6) and who experience a COPD exacerbation will be asked within 56 days to participate in a cohort-nested prospective randomised controlled trial (RCT). In this RCT, the intervention group will receive a strict physical therapy programme for patients with COPD. This protocol-directed physical therapy (pdPT) will be compared to a control group that will receive sham-treatment, meaning no or very low-intensity exercise training (ST). An economic evaluation will be embedded in the RCT. Anthropometric measurements, comorbidities, smoking, functional exercise capacity, peripheral muscle strength, physical activity level, health related quality of life, patients' perceived benefit, physical therapy compliance, motivation level, level of effective mucus clearance, exacerbation symptoms and health care contacts due to COPD will be recorded. Follow-up measurements are scheduled at 3 and 6 weeks, 3, 6, 12 and 24 months after inclusion.

Discussion: Ways to minimise potential problems regarding the execution of this study will be discussed.

Trial registration: The Netherlands National Trial Register NTR1972.

Figure 1

Framework of the study: a cohort-nested, prospective, randomised controlled trial. Definition of abbreviations: COPD = Chronic Obstructive Pulmonary Disease; RCT = Randomised Controlled Trial; Tiffeneau < 0.6 = Tiffeneau index (FEV₁/VC) < 0.6*; FEV₁ = Forced Expiratory Volume in one second*; FVC = Forced Vital Capacity*; GOLD I = mild COPD, FEV₁/FVC < 0.7 and FEV₁ ≥ 80% of predicted*; GOLD II = moderate COPD, FEV₁/FVC < 0.7 and 50% ≤ FEV₁ < 80% of predicted*; GOLD III = severe COPD, FEV₁/FVC < 0.7 and 30% ≤ FEV₁ < 50% of predicted*; GOLD IV = very severe COPD, FEV₁/FVC < 0.7 and FEV₁ < 30% of predicted or FEV₁ < 50% of predicted* plus chronic respiratory failure. *All lung functions are post-bronchodilator values.

Figure 2

Flowchart of the RCT. Definition of abbreviations: COPD = chronic obstructive pulmonary disease; pdPT = protocol-directed physical therapy; ST = sham-treatment, including no or very low-intensity exercise training.

Figure 3

Planning of outcome measurements in the RCT. The diary cards are not included in the Figure, but they are used by the patient every day of every month until T₆. In the cohort, the baseline measurement is followed by the same measurements as on T₃ in the RCT and are repeated every three months for at least twelve consecutive months. Definition of abbreviations: T₀ = baseline measurement; T₁ – T₁₀ = consecutive measurements in time after the baseline measurement; A = Anthropometric measures; B = Bicycle test results (maximal cardiopulmonary exercise test (CPET)); S = Spirometry results; 6 = 6MWT + Borg score and mGUG + Borg; M = peripheral muscle strength; P = physical activity in daily life with accelerometer; Q = CCQ*, CRQ-SR, EQ-5D*, DS14, MRC and level of effective mucus clearance, level of motivation, physical activity, physical therapy compliance*; C = questionnaire to assess direct and indirect costs; and G = Global Perceived Effect*. Measurement occasions are explained in the Table above the Figure. *The only measurements on T₁ and T₂.