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NCT Number: NCT01503164

Effects of Continuous Positive Airway Pressure (CPAP) on Glucose Metabolism

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.

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Key information

Conditions

Obstructive Sleep Apnea Apnea Diabetes Mellitus Diabetes Mellitus, Type 2 Dyssomnias Endocrine System Diseases Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Metabolic Diseases Nervous System Diseases Nutritional and Metabolic Diseases Respiration Disorders Respiratory Tract Diseases Sleep Apnea Sleep Apnea Syndromes Sleep Apnea, Obstructive Sleep Disorders, Intrinsic Sleep Wake Disorders Sleep-Disordered Breathing

Age range

21 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Johns Hopkins Bayview Medical Center

Baltimore, Maryland, 21224, United States

About this study

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).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Ability to give informed consent
  • Obstructive sleep apnea (untreated)
  • Ability to comply with study-related assessments

Exclusion criteria

  • Inability to consent or commit to the required visits
  • Diabetes mellitus (fasting glucose > 126 mg/dl)
  • Use of insulin or oral hypoglycemic agent
  • Weight change of 10% in last six months
  • Use of oral steroids in the last six months
  • Severe pulmonary disease (i.e., COPD)
  • Renal or hepatic insufficiency
  • Recent Myocardial Infarction (MI) or stroke (< 3 months)
  • Occupation as a commercial driver
  • Active substance use
  • Untreated thyroid disease
  • Pregnancy
  • Anemia (Hematocrit < 30%)
  • Any history of seizures or other neurologic disease
  • Poor sleep hygiene or sleep disorder other than sleep apnea
  • Excessive subjective sleepiness (Epworth score > 18)

Treatment and study plan

Positive Pressure Therapy (PAP)

Device

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.

Other names: CPAP

Lifestyle Counseling

Behavioral

Subjects randomized to the lifestyle (and nutritional) counseling arm will be given advice on a balanced dietary and exercise plan.

Other names: Dietary and Lifestyle Counseling

Primary outcomes

  1. Insulin Sensitivity (SI)

    Time frame: Baseline

    Insulin sensitivity will be determined with the insulin-modified frequently sampled intravenous glucose tolerance test (IVGTT) before and 2-months after study intervention. This test requires administration of a weight-adjusted dose of D50W as an IV bolus at time "zero". After the glucose bolus, blood samples are drawn at the scheduled times for 3-hours. At the 20-minute mark, a weight-adjusted dose of regular insulin is administered. The resulting serum is analyzed for glucose and insulin and the "minimal model" (MINMOD) will be used to derive insulin sensitivity. A low SI signifies low insulin sensitivity and high SI represents high insulin sensitivity.

  2. Insulin Sensitivity (SI)

    Time frame: 2 months after intervention

    Insulin sensitivity will be determined with the insulin-modified frequently sampled intravenous glucose tolerance test (IVGTT) before and 2-months after study intervention. This test requires administration of a weight-adjusted dose of D50W as an IV bolus at time "zero". After the glucose bolus, blood samples are drawn at the scheduled times for 3-hours. At the 20-minute mark, a weight-adjusted dose of regular insulin is administered. The resulting serum is analyzed for glucose and insulin and the "minimal model" (MINMOD) will be used to derive insulin sensitivity. A low SI signifies low insulin sensitivity and high SI represents high insulin sensitivity.

Secondary outcomes

  1. Glucose Effectiveness (SG)

    Time frame: Baseline

    Glucose effectiveness is the ability for glucose to move intracellularly in the absence of insulin. It is a parameter that results from the MINMOD analysis of the serum glucose and insulin levels derived from the frequently sampled intravenous glucose tolerance test. Low SG indicates a lower predisposition for glucose disposal independent of any effects of insulin.

  2. Glucose Effectiveness (SG)

    Time frame: 2 months after intervention

    Glucose effectiveness is the ability for glucose to move intracellularly in the absence of insulin. It is a parameter that results from the MINMOD analysis of the serum glucose and insulin levels derived from the frequently sampled intravenous glucose tolerance test. Low SG indicates a lower predisposition for glucose disposal independent of any effects of insulin.

  3. Disposition Index (DI)

    Time frame: Baseline

    The disposition index is the mathematical product of insulin sensitivity (SI) and acute insulin response to glucose (AIRG) both of which are derived from the MINMOD analysis of the frequently sampled intravenous glucose tolerance test data. A low DI is indicative of a higher risk of developing diabetes.

  4. Disposition Index (DI)

    Time frame: 2 months after intervention

    The disposition index is the mathematical product of insulin sensitivity (SI) and acute insulin response to glucose (AIRG) both of which are derived from the MINMOD analysis of the frequently sampled intravenous glucose tolerance test data.

  5. Acute Insulin Response to Glucose (AIRG)

    Time frame: Baseline

    The acute insulin response to glucose (AIRG) value is derived from the MINMOD analysis of the glucose and insulin levels obtained during the frequently sampled intravenous glucose tolerance test. A low AIRG indicates decreased ability of the pancreas to secrete insulin.

  6. Acute Insulin Response to Glucose (AIRG)

    Time frame: 2 months after intervention

    The acute insulin response to glucose (AIRG) value is derived from the MINMOD analysis of the glucose and insulin levels obtained during the frequently sampled intravenous glucose tolerance test. A low AIRG indicates decreased ability of the pancreas to secrete insulin.

  7. Endothelial Function

    Time frame: Baseline

    Endothelial function will be assessed using peripheral arterial tonometry using the Endo-PAT device. Using the EndoPat device, the relative vasoconstriction of occluded versus non-occluded arms was derived and provided the relative hyperemic index.

  8. Endothelial Function

    Time frame: 2 month after intervention

    Endothelial function will be assessed using peripheral arterial tonometry using the Endo-PAT device. Using the EndoPat device, the relative vasoconstriction of occluded versus non-occluded arms was derived and provided the relative hyperemic index.

  9. Area Under the Curve Assessed by Oral Glucose Tolerance Test

    Time frame: Baseline

    Results of the oral glucose tolerance test will be analyzed using indices derived from the serial glucose and insulin levels over the 2 hour period. This will be the area under the glucose/ insulin curves

  10. Area Under the Curve Assessed by Oral Glucose Tolerance Test (OGTT)

    Time frame: 2 month after intervention

    Results of the oral glucose tolerance test will be analyzed using indices derived from the serial glucose and insulin levels over a 2 hour period 2 months post intervention. This will be the area under the glucose/ insulin curves

Sponsors and collaborators

Lead sponsor

Johns Hopkins University

Other

Collaborators

  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

Sleep, Obesity, and Metabolism in Normal and Overweight Subjects: Effects of CPAP on Glucose Metabolism

Acronym: SOMNOS

Important dates

Study start
2011
Primary completion
2013
Study completion
2013
First posted
Jan 2, 2012
Registry last updated
Oct 19, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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