[BMJ Publishing Group Ltd and British Thoracic Society British Thoracic Society Winter Meeting 2017, QEII Centre Broad Sanctuary Westminster London SW1P 3EE, 6 to 8 December 2017, Programme and Abstracts - ()] Hot topics in home-based mechanical ventilation - S38 Home mechanical ventilation (hmv) and home oxygen therapy (hot) following an acute exacerbation of copd in patients with persistent hypercapnia: predicting 1 year admission-free survival in the hot-hmv uk trial