Clinical Aspects of Obesity Hypoventilation Syndrome

Abstract

Obesity hypoventilation syndrome (OHS) represents the most severe form of sleep disordered breathing occurring in obese individuals and results in hypoventilation, both during sleep and in wakefulness. OHS is associated with significant morbidity and increased health, social and economic burdens for the individual and health care system. Mortality in OHS has been shown to be significantly higher than in individuals with eucapnic obstructive sleep apnoea (OSA), even when effective treatment with positive airway pressure (PAP) therapy has been established. In these individuals, it is cardiovascular disease rather than respiratory failure, which is the most common cause of death. The work presented in this thesis focuses on 3 aspects of OHS: development of a predictive model for early identification of obese patients with nocturnal-only hypoventilation, thought to represent an earlier stage of OHS; comparison of neurocognitive function pre and post PAP therapy in OHS and equally obese individuals with OSA; and the impact of PAP therapy on cardio-metabolic and renal biomarkers in OHS patients, comparing this with equally obese individuals with OSA.