Weight and metabolic effects of CPAP in obstructive sleep apnea patients with obesity

Respir Res. 2011 Jun 15;12(1):80. doi: 10.1186/1465-9921-12-80.


Background: Obstructive sleep apnea (OSA) is associated with obesity, insulin resistance (IR) and diabetes. Continuous positive airway pressure (CPAP) rapidly mitigates OSA in obese subjects but its metabolic effects are not well-characterized. We postulated that CPAP will decrease IR, ghrelin and resistin and increase adiponectin levels in this setting.

Methods: In a pre- and post-treatment, within-subject design, insulin and appetite-regulating hormones were assayed in 20 obese subjects with OSA before and after 6 months of CPAP use. Primary outcome measures included glucose, insulin, and IR levels. Other measures included ghrelin, leptin, adiponectin and resistin levels. Body weight change were recorded and used to examine the relationship between glucose regulation and appetite-regulating hormones.

Results: CPAP effectively improved hypoxia. However, subjects had increased insulin and IR. Fasting ghrelin decreased significantly while leptin, adiponectin and resistin remained unchanged. Forty percent of patients gained weight significantly. Changes in body weight directly correlated with changes in insulin and IR. Ghrelin changes inversely correlated with changes in IR but did not change as a function of weight.

Conclusions: Weight change rather than elimination of hypoxia modulated alterations in IR in obese patients with OSA during the first six months of CPAP therapy.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adiponectin / blood
  • Appetite Regulation
  • Biomarkers / blood
  • Blood Glucose / metabolism
  • Body Weight*
  • Chi-Square Distribution
  • Continuous Positive Airway Pressure*
  • Female
  • Ghrelin / blood
  • Humans
  • Insulin / blood
  • Insulin Resistance*
  • Linear Models
  • Male
  • Middle Aged
  • Obesity / complications*
  • Obesity / metabolism
  • Obesity / physiopathology
  • Resistin / blood
  • Sleep
  • Sleep Apnea, Obstructive / etiology
  • Sleep Apnea, Obstructive / physiopathology
  • Sleep Apnea, Obstructive / therapy*
  • Texas
  • Time Factors
  • Treatment Outcome


  • ADIPOQ protein, human
  • Adiponectin
  • Biomarkers
  • Blood Glucose
  • GHRL protein, human
  • Ghrelin
  • Insulin
  • RETN protein, human
  • Resistin