FIG. 54: There was a clear improvement in patients in the intervention arm with the addition of home NIV, as highlighted in this Figure:[1] PaCO2 improved by >0.5 kPa during the first 3 months of the trial (P=0.015), although the significance of the improvements in respiratory failure were attenuated towards the end of the trial.[1]

There are several factors that may explain this attenuation. By 12 months there was a reduction in the number of patients achieving this level of follow-up owing either to death or to patient withdrawal, and of course this reduced the power to detect a significant difference at this time point.

Further, inclusion of the safety criteria for addition of home ventilation in the initial HOT arm of the trial showed that by 6 months approximately 50% of the patients had home NIV, therefore suggesting amelioration or improvement in their respiratory failure may have been due to this addition, although the analysis was based on intention-to-treat.