A systematic review of exercise studies for individuals hospitalized with an acute exacerbation of chronic obstructive pulmonary disease: Focus on the principles of exercise training.

Background: For exercise interventions to be effectively reproduced or applied in a "real world" clinical setting, clinical trials must thoroughly document all components of the exercise prescription and ensure that participants adhere to each component. However, previous reviews have not critically examined the quality of exercise prescription of inpatient Pulmonary Rehabilitation (PR) programs.

Objective: The objectives of this review were to evaluate the (a) application of the principles of exercise training, (b) reporting of the frequency, intensity, time and type (FITT) components of exercise prescription, and (c) reporting of patient's adherence to the FITT components in intervention studies for patients admitted to hospital for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods: Relevant scientific databases were searched for randomized controlled trials (RCTs) that compared in-hospital PR with usual care for people hospitalized with AECOPD. Title and abstract followed by full-text screening were conducted independently by two reviewers. Data were extracted and synthesized to evaluate the application of the principles of exercise training and the reporting/adherence of the FITT components.

Results: Twenty-seven RCTs were included. Only two applied all principles of exercise training. Specificity was applied by 70%, progression by 48%, overload by 37%, initial values by 89% and diminishing returns and reversibility by 37% of trials. Ten trials adequately reported all FITT components. Frequency and type were the components most reported (85% and 81%, respectively), while intensity was less frequently reported (52%). Only three trials reported on the patient's adherence to all four components.

Conclusions: Studies have not adequately reported the exercise prescription in accordance with the principles of exercise training nor reported all the FITT components of the exercise prescription and patient's adherence to them. Therefore, interpretation of the current literature is limited and information for developing exercise prescriptions to individuals hospitalized with an AECOPD is lacking.