Efficacy and safety of erythrocytapheresis in chronic mountain sickness: a randomised controlled trial protocol (ESCAPE-CMS).

introductionChronic mountain sickness (CMS) is a clinical syndrome affecting more than 4 million individuals living at high altitudes, primarily characterised by excessive polycythaemia. Current CMS consensus recommends therapies targeting haematocrit (HCT), such as phlebotomy or isovolemic haemodilution. However, the clinical benefit of HCT-reduction strategies in CMS has yet to be established. This trial aims to evaluate whether erythrocytapheresis, regarded as one of the most precise and effective approaches for HCT-reduction, could improve clinical outcomes in patients with CMS. METHODS AND ANALYSIS: Efficacy and safety of erythrocytapheresis in chronic mountain sickness is an investigator-initiated, multicentre, randomised controlled superiority trial with blinded outcome assessment. A total of 112 eligible CMS patients will be consecutively randomised to receive either standard care alone or standard care plus erythrocytapheresis with a 1:1 ratio. The primary efficacy endpoint is the net change in CMS symptom score assessed at 48 hours post-erythrocytapheresis or prior to discharge for controls. The primary safety outcome is treatment-related adverse events before discharge. The primary outcome will be analysed using an analysis of covariance, with a clinical threshold for superiority. ETHICS AND DISSEMINATION: Ethics approval was obtained from the Medical Ethics Committees of the coordinating centre (Xinqiao Hospital, 2020-014-02) and each participating centre. Written informed consent will be acquired prior to enrolment. The trial results will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04557995.