Influence of nCPAP on Metabolic Consequences Associated With OSAS
Condition: Obstructive Sleep Apnea Syndrome; Obesity
MeSH terms: Apnea; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Syndrome
Study type: Interventional

Summary: 
      Context: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular morbidity.
      Recurrent episodes of occlusion of upper airways during sleep result in hormonal changes that
      may predispose to high cardiovascular risk.These risks can rapidly be reduced by effective
      nasal continuous positive airway pressure (nCPAP) therapy Objective: To evaluate hypothalamic
      pituitary adrenal axis, insulin resistance, blood pressure values and adipokines in severe
      obese patients with and without OSAS and to determine if continuous positive airway pressure
      therapy (nCPAP) influenced responses.
    

Detailed description: 
      Background: There is evidence that obstructive sleep apnea syndrome (OSAS) increases the risk
      of cardiovascular events. Sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA)
      axis activation may be the mechanism of this relationship. We evaluate HPA axis and metabolic
      consequences in obese patients with and without OSAS and we determine if continuous positive
      airway pressure therapy (nCPAP) influenced responses.

      Methods: Plasma inflammatory cytokines, insulin resistance index, 24-hour ambulatory blood
      pressure monitoring and overnight cortisol suppression test with 0.25 mg of dexamethasone
      were performed in 22 severe obese patients with OSAS and 23 obese controls. Ten patients with
      severe apnea were re-evaluated three months after nCPAP therapy.

      Results: Body mass index, abdominal circumference, blood pressure levels and insulin
      resistance indexes of OSAS patients and obese controls were very similar. In OSAS patients,
      adiponectin (p<0.05) and salivary cortisol suppression pos DEX (p<0.05) were lower, while
      heart rate (p<0.05) and TNF-alpha levels (p<0.05) were higher compared with obese controls.
      After nCPAP therapy, patients showed a reduction in heart rate (p=0.036) and a higher
      cortisol suppression after dexamethasone (p=0.001) and there were no differences in insulin
      resistance (HOMA p=0.139), arterial blood pressure (p=0.183) and adipokines compared with
      baseline. Cortisol suppression was positively correlated with the improvement of apnea
      hypopnea index while on nCPAP therapy (r= 0.799, p=0.010).

      Conclusions: Patients with OSAS present nocturnal hypercortisolism, hyperactivity of
      sympathetic central nervous system, a higher degree of inflammation and hypoadiponectinemia
      independent of the body mass index. Furthermore, hyperactivity of HPA axis and sympathetic
      nervous system are recovered by nCPAP.
    

Intervention name(s): nasal continuous positive airway pressure
Intervention type(s): Procedure
Intervention description(s): After an average interval of three months, 10 patients with severe OSAS (AHI of more than 30 events per hour of sleep) treated with a mean nCPAP pressure of 11.2 ± 0.7 cm of H2O were reassessed and all mentioned measurements above were repeated
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Sleep apnea,; adiponectin ,; HPA axis