Metabolic assessments of neurostimulation therapy to reduce apnea (MANTRA) trial: rationale and methods

To investigate the effects of hypoglossal nerve stimulation (HGNS) therapy on energy balance and insulin resistance among patients stabilized on HGNS.

In this randomized, within-subject crossover trial, we compare energy balance and insulin resistance during active HGNS ("HGNS-on") versus HGNS withdrawal ("HGNS-off") among 30 patients with OSA who have been stabilized on HGNS for ≥3 months. Participants will undergo between 2-4 weeks of each study phase (HGNS-on and HGNS-off), with the duration of HGNS-on and HGNS-off standardized within participants. Between the two study phases (HGNS-on and HGNS-off), patients resume HGNS for 1 week. At the end of each study phase, participants undergo fasting anthropometric measurements, blood sample collection, and home sleep testing. A subset of participants undergo additional assessments of energy expenditure (via doubly labeled water technique) and energy intake.

The primary outcome is energy balance, as calculated from the difference between energy expenditure and energy intake. The secondary outcome is insulin resistance, as assessed by the homeostatic model assessment for insulin resistance.

There is a dearth of mechanistic data examining the metabolic effects of HGNS. We present methods of the Metabolic Assessments of Neurostimulation Therapy to Reduce Apnea (MANTRA) trial, the first randomized crossover study designed to examine the metabolic effects of HGNS.