Question: Is this describing a (1) directly correlative relationship, (2) conditionally causative relationship, (3) causative relationship, or (0) no relationship.

This pilot study showed in real life conditions the possibility of a  systematic switch of NIV to CPAP, in most stable patients with OHS, with similar  efficacy on diurnal and nocturnal alveolar gas exchange, quality of life and quality of sleep.
user
This is a directly correlative relationship
assistant