FIG. 16: The trial was a UK-based, multicenter, randomized clinical trial that was powered to detect a reduction in readmission rate of approximately 55% at 1 year and a reduction to 25% NIV use.[1] The trial design required 116 patients to be recruited to achieve a power level of 80%, assuming a dropout rate of approximately 22% over the trial period.

Because the clinical trial was relatively modest in size, owing to the nature of recruiting patients to this intervention, the design minimized the number of important variables that might predict admission-free survival, in order to ensure balance between the groups.