Dynamic chest radiography evaluation of the effects of tiotropium/olodaterol combination therapy in COPD: EMBODY study protocol

Rationale: To date, there is limited evidence of the effects of bronchodilators on the respiratory dynamics in chronic obstructive pulmonary disease (COPD). Dynamic chest radiography (DCR) is a novel radiographic modality that provides real-time, objective, and quantifiable kinetic data, including changes in the lung area, diaphragm kinetics, and pulmonary ventilation during respiration, at a lower radiation dose than fluoroscopic or computed tomography imaging. Aim: This study aims to evaluate the effects of bronchodilator therapy on the respiratory kinetics in patients with COPD using DCR. Methods: This is an open-label, prospective, single-center, comparative study. A total of 35 patients with COPD, aged 40-85 years, with a forced expiratory volume in the first second of 30-80% will be enrolled. After a 2-week washout period, patients will receive tiotropium/olodaterol therapy for 6 weeks. Treatment effects will be evaluated based on DCR, pulmonary function tests, and patient-related outcomes obtained before and after treatment. The primary endpoint is the change in lung area during respiration as evaluated by DCR after the treatment. Secondary endpoints include differences in other DCR parameters (diaphragm kinetics, tracheal diameter change, and maximum pixel value change rate), pulmonary function test results, and patient-related outcomes between pre- and post-therapy. All adverse events will be reported. Conclusions: The EMBODY study is the first to evaluate the effects of bronchodilator therapy on the respiratory kinetics in COPD using DCR. The study could provide additional evidence of the potential of DCR for evaluating COPD therapy.