title: Effect of Short Term CPAP Therapy in Obstructive Sleep Apnea Patients with Metabolic Syndrome.
abstract: BACKGROUND
  Patients of obstructive sleep apnea (OSA) with metabolic syndrome (MetS) are at increased risk of cardiovascular morbidity and mortality. The role of oxidative stress in pathogenesis of OSA and MetS has been widely reported. Continuous positive airway pressure (CPAP) therapy remains the first-line of treatment in OSA. The beneficial effect of long term CPAP therapy in OSA is well-known. However, the effect of short term CPAP on the components of MetS and oxidative stress-antioxidant levels is still unclear.
  
  
  OBJECTIVE
  The present study explored the effects of one night of CPAP therapy on the oxidant-antioxidant status and components of MetS in patients of OSA with MetS.
  
  
  METHODS
  Twenty adult males and postmenopausal females with MetS and symptoms suggestive of OSA were enrolled in the study. None of the subjects were smoker or alcoholic. They did not consume any drugs that would alter their antioxidant levels. Overnight polysomnography was done to confirm diagnosis and assess CPAP pressure. Following which they spent one night in the sleep lab for CPAP therapy. Blood pressure data and blood samples were collected at baseline and after CPAP. Collected samples were transferred immediately to the laboratory for analysis of serum thiol, lipid peroxidation, insulin resistance (HOMA-IR) and lipid profile.
  
  
  RESULTS
  Paired t-test with two-tail significance was used to compare the changes in study parameters in the same patient before and after treatment. The antioxidant level increased and oxidative stress decreased as evidenced by serum thiol concentration (204.2±65.7 vs 254.9±72 μmol/L, p<0.001) and lipid peroxidation levels (13.1±6.2 vs 8.4±3.1 μmol/L, p<0.01).There was a significant decrease in both systolic (132.1±16.1 vs 127.2±14.3 mmHg, p<0.01) and diastolic blood pressure (86.4±9.4 vs 81.2±9.8 mmHg, p<0.01) after one night of CPAP. However, there was no change in lipid parameters and the reduction seen in insulin resistance was not statistically significant.
  
  
  CONCLUSIONS
  One night of CPAP therapy seems to be helpful in reducing oxidative stress, improving antioxidant levels and decreasing the severity of various components of MetS.
authors.affiliation: Assistant Professor, Department of Physiology, SRM MCH & RC , Chennai, India .
authors.forename: Kanimozhi
authors.initials: K
authors.lastname: S
authors.affiliation: Associate Professor, Department of Paediatrics, SRM MCH & RC , Chennai, India .
authors.forename: Balaji
authors.initials: B
authors.lastname: C
authors.affiliation: Professor and HOD, Department of Physiology, SRM MCH & RC , Chennai, India .
authors.forename: Saravanan
authors.initials: S
authors.lastname: A
authors.affiliation: Professor and HOD, Department of Physiology, V.P. Chest Institute , Delhi, India .
authors.forename: Ravi
authors.initials: R
authors.lastname: K
keywords: Blood pressure; Insulin resistance; Lipid profile; Oxidative stress