Effects of Continuous Positive Airway Pressure (CPAP) on Glucose Metabolism
Condition: Obstructive Sleep Apnea; Sleep Apnea; Sleep-disordered Breathing
MeSH terms: Apnea; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Respiratory Aspiration
Study type: Interventional

Summary: 
      Obstructive sleep apnea affects approximately 2-4% of middle-aged adults in the general
      population and is associated with several medical conditions including hypertension and
      coronary artery. Research over the last decade has shown that obstructive sleep apnea may
      also increase the propensity for insulin resistance, glucose intolerance, and type 2 diabetes
      mellitus. Positive airway pressure (PAP) is the first line therapy for the treatment of
      obstructive sleep apnea. While PAP therapy has several favorable effects such as improvements
      in daytime sleepiness and quality of life, it is not clear whether using PAP therapy can
      alter metabolic risk. The overall objective of this study is to examine whether treatment of
      obstructive sleep apnea with positive airway pressure therapy improves glucose tolerance and
      insulin sensitivity. The primary hypothesis of this study is that PAP therapy of obstructive
      sleep apnea will improve in insulin sensitivity and glucose metabolism.
    

Detailed description: 
      Type 2 diabetes mellitus is one of the most prevalent medical conditions, affecting a
      staggering 246 million people worldwide. Obstructive sleep apnea is a relatively common and
      often undiagnosed condition in the general population. Cross-sectional studies of clinic and
      population-based samples suggest that up to 40% of patients with obstructive sleep apnea have
      type 2 diabetes and up to 75% of patients with type 2 diabetes have obstructive sleep apnea.
      There is increasing evidence that the pathophysiological features of intermittent hypoxia and
      sleep fragmentation may be responsible for altering glucose homeostasis and worsening insulin
      sensitivity. The mechanisms through which obstructive sleep apnea impairs glucose metabolism
      are largely unknown. While intermittent hypoxemia and sleep fragmentation are likely to play
      an essential role, the relative contribution of each in the causal pathway remains to be
      determined. Moreover, whether the adverse effects of intermittent hypoxia and sleep
      fragmentation are mediated through an increase in sympathetic nervous system activity,
      alterations in corticotropic function, and/or systemic inflammation is not known.
      Furthermore, it remains to be determined whether positive pressure therapy for obstructive
      sleep apnea has salutary effects on glucose metabolism. Many of the available studies
      examining the effects of PAP on glucose tolerance and insulin sensitivity are plagued by
      small sample sizes, lack of a control group, and limited data on compliance with positive
      pressure therapy. The current study will assess, using a community-based sample, whether
      treatment of obstructive sleep apnea with positive pressure therapy will improve insulin
      sensitivity, as assessed by the frequently sample intravenous glucose tolerance test (primary
      outcome measure).
    

Intervention name(s): Positive Pressure Therapy (PAP); LifeStyle Counseling
Intervention type(s): Device; Behavioral
Intervention description(s): Positive pressure therapy is the standard of care for managing obstructive sleep apnea. It entails wearing a mask that is connected to the PAP device which deliver pressure to the upper airway during sleep.; Subjects randomized to the lifestyle (and nutritional) counseling arm will be given advice on a balanced dietary and exercise plan.
Other intervention name(s): CPAP; Dietary and Lifestyle Counseling
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Obstructive sleep apnea; Sleep Apnea; Sleep-disordered breathing; Insulin sensitivity; Glucose tolerance; Type 2 diabetes