Obesity hypoventilation syndrome (OHS) is a condition that occurs in small percentage of obese people that causes high carbon dioxide and low oxygen levels in the blood. OHS is associated with respiratory failure, pulmonary hypertension, and death. The cause of OHS is unclear. Since not all obese people develop OHS, it is believed that hormone imbalances can contribute to the breathing problem. Some diets can change the body's hormones. For example, low-carbohydrate, high fat "ketogenic" diets (KD) may decrease insulin and glucose levels and increase sensitivity to other hormones. The investigators hypothesize that a KD will improve breathing in OHS patients, even in the absence of weight loss.
Obesity hypoventilation syndrome (OHS) is a condition that occurs in small percentage of obese people, that leads to high carbon dioxide levels and low oxygen levels in the blood. OHS is associated with respiratory failure, pulmonary hypertension, hospital admissions, and death. Unfortunately, there is no treatment for OHS besides massive weight loss which often requires bariatric surgery. In this study, the investigators are examining whether switching from a regular diet to a ketogenic diet will improve breathing, oxygen, and carbon dioxide levels in OHS patients. After a few days-weeks on KD, hormone changes are known to occur and the investigators are examining whether these hormonal changes could stimulate breathing. This is a pilot study to examine the effects of a 12 day KD on OHS. The outcomes of the study include blood oxygen, carbon dioxide levels, plasma levels of hormones such as insulin, leptin, sleep studies, body composition a, weight, and metabolic rate.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
24
Subjects will undergo ketogenic diet at a 2.5:1 (fat: carb + protein) ratio for a 2-week period.
Johns Hopkins Bayview Medical Center
Baltimore, Maryland, United States
Change in Awake venous carbon dioxide (PvCO2) Level
Measured in mmHg.
Time frame: Baseline (pre keto diet) and 2 weeks post keto diet
Change in Venous pH
Measured in moles per liter.
Time frame: Once per week, over 4 weeks
Change in Glucose level
Measured in g/dL.
Time frame: Once per week, over 4 weeks
Change in Insulin level
Measured in mIU/L.
Time frame: Once per week, over 4 weeks
Change in leptin level
Measured in ng/mL.
Time frame: Once per week, over 4 weeks
Change in beta-Hydroxybutyrate level
Measured in mg/dL.
Time frame: Once per week, over 4 weeks
Glucose profile
Using continuous glucose monitoring (CGM), to measured glucose level (g/dL) each day at home.
Time frame: Continuously measured over 4 weeks
Change in Body weight (kg)
Time frame: Once per week, over 4 weeks
Change in Oxygen saturation
Measured as a percentage.
Time frame: Once per week, over 4 weeks
Change in Blood Pressure
Measured in mmHg.
Time frame: Once per week, over 4 weeks
Change in percentage of body fat
The investigators will measure percentage body fat using the Bioelectrical impedance analysis (BIA).
Time frame: Once every 2 weeks, over 4 weeks
Change in Apnea Hypopnea Index
The apnea hypopnea index (AHI) is derived from combined information from EEG signals, flow sensors, respiratory belts, and carbon dioxide censors and is a measure of severity of sleep apnea. AHI \< 5 is considered normal. AHI 5-15 is considered mild sleep apnea. AHI 15-30 is considered moderate sleep apnea. AHI \>30 is considered severe sleep apnea.
Time frame: Once every 2 weeks, over 4 weeks
Change in LDL Cholesterol
Measured in mg/dL.
Time frame: Once per week, over 4 weeks
Change in HDL Cholesterol
Measured in mg/dL.
Time frame: Once per week, over 4 weeks
Change in Triglyceride level
Measured in mg/dL.
Time frame: Once per week, over 4 weeks
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