Overall objective: To understand the feasibility of performing a randomized trial using a simple, minimally-invasive postural therapy approach to improve sleep disordered breathing (SDB).
Specific Aims: * To examine the relative efficacy of postural therapy (a 15-degree wedge mattress) on measures of chronic cardiometabolic stress in high altitude residents. * To determine the tolerability of postural therapy. Primary outcomes, at 4 and 8 weeks: * Mean nocturnal oxyhemoglobin saturation (SPO2) * Apnea-hypopnea index (AHI). Secondary outcomes * Markers of hypoxemia exposure: the investigators will evaluate for differences in average hemoglobin and erythropoietin concentrations between intervention groups using t-tests or Wilcoxon rank sum tests, as considered appropriate. If transformations are necessary, the investigators will use Box-Cox power transform to identify the best transformation for the investigators' data. * Markers of metabolic dysfunction: the investigators will evaluate for differences in average Glycated hemoglobin test (HbA1c), homeostatic model assessment of insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol (LDL), High-density lipoprotein cholesterol (HDL), triglycerides, SVEGF-R1 , and soluble Vascular Endothelial Growth Factor (SVEGF-1) concentrations between intervention groups using t-tests or Wilcoxon rank sum tests, as appropriate. If transformations are necessary, the investigators will use Box-Cox power transform to identify the best transformation for the investigators' data. * Markers of cardiometabolic stress: the investigators will evaluate for differences in average systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse, and % change in endothelial function (reactive hyperemia index) as assessed by brachial artery reactivity testing (BART) between intervention groups using t-tests or Wilcoxon rank sum tests, as considered appropriate. * Adherence (the average number of nights during the 8-week period that participants slept on the wedge mattress),
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
54
Study participants randomized to the interventional arm will be instructed to sleep on inclined wedge mattress.
Prisma Org
Puno, Peru
Change in Respiratory Disturbance Index (RDI)
The investigators will measure a change in Respiratory Disturbance Index (RDI) defined as an oxygen desaturation of at least 4 percent associated with autonomic signs of arousal. Specifically, autonomic arousals are defined as concurrent rises in heart rate and attenuation of arterial tonometry. Normal \< 5 percent 5 percent \< Mild \< 15 percent 15 percent \< Moderate \< 30 percent Severe \> 30 percent
Time frame: Baseline, 4 weeks, 8 weeks
Change in Mean oxyhemoglobin saturation (percent) during sleep
The investigators will measure mean oxyhemoglobin saturation (%SaO2) during sleep as assessed by WatchPAT home sleep study at baseline and week 8.
Time frame: Baseline, 4 weeks, 8 weeks
Tolerability of postural therapy as assessed by adherence monitor
Adherence monitor will measure sleep over the set time points and tolerability is defined as a recorded time on the wedge for a minimum of 5 hours.
Time frame: 2, 4, 6 and 8 weeks
Change in average plasma hemoglobin concentration (g/dL)
Time frame: Baseline, 8 weeks
Change in average Glycated hemoglobin test (HbA1c)
This will measure percentage (%) of HbA1c in the blood.
Time frame: Baseline, 8 weeks
Change in serum erythropoietin (EPO) concentration
The concentration of EPO in the sample is expressed in International Units per litre (U/L) and is determined by calibration against a reference standard.
Time frame: Baseline, 8 weeks
Change in soluble Vascular Endothelial Growth Factor (SVEGF-1) concentrations
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Plasma levels of SVEGF-1 (pg/mL)
Time frame: Baseline, 8 weeks
Change in homeostatic model assessment of insulin resistance (HOMA-IR)
Units of measurement is mass units.
Time frame: Baseline, 8 weeks
Change in total plasma cholesterol level (mg/dL)
Time frame: Baseline, 8 weeks
Change in plasma low-density lipoprotein (LDL) cholesterol level (mg/dL)
Time frame: Baseline, 8 weeks
Change in plasma high-density lipoprotein (HDL) cholesterol level (mg/dL)
Time frame: Baseline, 8 weeks
Change in plasma triglyceride concentration (mg/dL)
Time frame: Baseline, 8 weeks
Change in Vascular endothelial growth factor receptor 1 (SVEGF-R1) concentration
Units of measurement pg/mL
Time frame: Baseline, 8 weeks
Change in mean blood pressure (mmHg)
Time frame: Baseline, 8 weeks
Change in Brachial Artery Reactivity Testing (BART) assessment
Assessed by endothelial function using high-frequency ultrasound visualized brachial artery reactivity testing. Endothelial function is characterized by flow-mediated vasodilation of the brachial artery, which is measured by comparing the brachial artery diameter at rest to the diameter after increased forearm blood flow (reactive hyperemia). Unit of measurement is mass units.
Time frame: Baseline, 8 weeks