title: The effect of continuous positive airway pressure treatment on insulin sensitivity in patients with obstructive sleep apnoea syndrome and type 2 diabetes.
abstract: BACKGROUND
  The obstructive sleep apnoea syndrome (OSA) is a frequent condition, as well as type 2 diabetes mellitus. Both diseases are characterized by insulin resistance.
  
  
  OBJECTIVE
  The aim of this study was to establish whether OSA is an independent risk factor for increased insulin resistance in diabetics. For this purpose, we tested the hypothesis that the insulin sensitivity in patients with type 2 diabetes and OSA can be improved by 2 days or 3 months of continuous positive airway pressure (CPAP) treatment.
  
  
  METHODS
  In 9 obese patients with type 2 diabetes and OSA [apnoea/hypopnoea index 43.1 +/- 21.3; body mass index (BMI) 37.3 +/- 5.6 kg/m2] and good glycaemic control on oral antidiabetics or on diet alone (HbA1c 6.4 +/- 0.7%), the insulin sensitivity index (ISI) was established by euglycaemic hyperinsulinaemic clamp tests at baseline, after 2 days and after 3 months of effective CPAP treatment.
  
  
  RESULTS
  ISI was unchanged after 2 days of CPAP treatment, but was significantly improved after 3 months (4.38 +/- 2.94 vs. 2.74 +/- 2.25 at baseline; p = 0.021), without any significant changes in BMI. Glycaemic control was unaffected after 3 months (HbA1c 6.3 +/- 0.6%; not significant). Fasting leptin levels showed no significant changes.
  
  
  CONCLUSIONS
  These results indicate that OSA itself is an independent risk factor for insulin resistance. This effect may be explained by the elevated sympathetic activity in OSA.
authors.affiliation: 1st Department of Medicine, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany. igor.harsch@med1.imed.uni-erlangen.de
authors.forename: Igor Alexander
authors.initials: IA
authors.lastname: Harsch
authors.forename: Simin Pour
authors.initials: SP
authors.lastname: Schahin
authors.forename: Kerstin
authors.initials: K
authors.lastname: Brückner
authors.forename: Martin
authors.initials: M
authors.lastname: Radespiel-Tröger
authors.forename: Florian S
authors.initials: FS
authors.lastname: Fuchs
authors.forename: Eckhart Georg
authors.initials: EG
authors.lastname: Hahn
authors.forename: Peter Christopher
authors.initials: PC
authors.lastname: Konturek
authors.forename: Tobias
authors.initials: T
authors.lastname: Lohmann
authors.forename: Joachim Hans
authors.initials: JH
authors.lastname: Ficker
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology; D016896:Treatment Outcome