Ventilators designed for home care provide clinicians with built-in software that records items such as compliance, leaks, average tidal volume, total ventilation, and indices of residual apnea and hypopnea. Recent studies have showed, however, an important variability between devices regarding reliability of data provided. In this study, we aimed to compare apnea-hypopnea indices (AHI) provided by home ventilators (AHINIV) versus data scored manually during polysomnography (AHIPSG) in subjects on noninvasive ventilation (NIV) for obesity-hypoventilation syndrome.