FIG. 57: Although HOT-HMV was not powered to assess mortality, we felt it was important to assess any impact on morality and also to investigate the causes of death in these patients, since in patients with mild COPD the cause of death can often be attributed to ischemic heart disease rather than COPD per se. However, the patients were recruited into this study with severe exacerbations of COPD and chronic respiratory failure, and the causes of death were almost always respiratory-related in 34 out of 35 cases over the 12-month trial period.[1] Although there was no statistically significant difference between the mortality rates in the HOT arm (orange line in the Figure) and the home NIV arm (blue line) over the 12-month period, there was a nonsignificant trend for the benefit of the home NIV arm.