Blood pressure response to treatment of obese vs non-obese adults with sleep apnea.

Many patients with obstructive sleep apnea (OSA), but not all, have a reduction in blood pressure (BP) with positive airway pressure (PAP) treatment. Our objective was to determine whether the BP response following PAP treatment is related to obesity. A total of 188 adults with OSA underwent 24-hour BP monitoring and 24-hour urinary norepinephrine collection at baseline. Obesity was assessed by waist circumference, body mass index, and abdominal visceral fat volume. Participants adherent to PAP treatment were reassessed after 4 months. Primary outcomes were 24-hour mean arterial pressure (MAP) and 24-hour urinary norepinephrine level. Obstructive sleep apnea participants had a significant reduction in 24-hour MAP following PAP treatment (-1.22 [95% CI: -2.38, -0.06] mm Hg; P = .039). No significant correlations were present with any of the 3 obesity measures for BP or urinary norepinephrine measures at baseline in all OSA participants or for changes in BP measures in participants adherent to PAP treatment. Changes in BP measures following treatment were not correlated with baseline or change in urinary norepinephrine. Similar results were obtained when BP or urinary norepinephrine measures were compared between participants dichotomized using the sex-specific median of each obesity measure. Greater reductions in urinary norepinephrine were correlated with higher waist circumference (rho = -0.21, P = .037), with a greater decrease from baseline in obese compared to non-obese participants (-6.26 [-8.82, -3.69] vs -2.14 [-4.63, 0.35] ng/mg creatinine; P = .027). The results indicate that the BP response to PAP treatment in adults with OSA is not related to obesity or urinary norepinephrine levels.

Physical Activity Following Positive Airway Pressure Treatment in Adults With and Without Obesity and With Moderate-Severe Obstructive Sleep Apnea.

STUDY OBJECTIVES: To examine the level of physical activity (PA) before and following positive airway pressure (PAP) treatment in adults who have obstructive sleep apnea (OSA) with obesity versus without obesity. METHODS: Simultaneous waist accelerometer and wrist actigraphy recordings were obtained in 129 adults with obesity and 69 adults without obesity and who had OSA prior to and following 4 months of PAP therapy and in 52 patients in a control group. Primary PA measurements were average steps per day on waist accelerometry and average counts per minute (CPM) per day on wrist actigraphy. RESULTS: At baseline, participants with obesity and OSA exhibited fewer steps per day on waist accelerometer and fewer CPM per day on wrist actigraphy compared to participants without obesity and with OSA (despite similar apnea-hypopnea index between groups). Following PAP treatment, participants with OSA had modestly increased CPM per day on wrist actigraphy (17.69 [95% confidence interval (CI), 5.67-29.71], P = .005) and increased light PA time (0.26 [95% CI, 0.07-0.44] hours, P = .008) on waist accelerometer. Participants without obesity and with OSA had greater improvements in PA measures on average compared to participants with obesity and OSA, although the differences were not statistically significant. Weight increased following PAP treatment in the participants with obesity and OSA (1.71 [95% CI, 0.41-3.02] kg, P = .010) but was unchanged in the group without obesity (0.93 [95% CI, -0.89 to 2.76] kg, P = .311). CONCLUSIONS: Compared to study participants without obesity and with OSA, participants with obesity and OSA had reduced PA at baseline. PA increased significantly in participants without obesity, with OSA, and who were adherent to PAP treatment. Results indicate that treatment of OSA is unlikely to be associated with a change in PA in adults with obesity and OSA and help explain the absence of weight loss following PAP treatment in adults with OSA. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov, title: The Effects of Treating Obese and Lean Patients With Sleep Apnea (PISA), identifier: NCT01578031, URL: https://clinicaltrials.gov/ct2/show/NCT01578031.

Carotid Artery Wall Thickness in Obese and Nonobese Adults With Obstructive Sleep Apnea Before and Following Positive Airway Pressure Treatment.

Study objectives: Debate persists as to whether obstructive sleep apnea (OSA) is an independent risk factor for atherosclerosis. The purpose of this study was to compare carotid intima-media thickness (IMT), an early sign of atherosclerosis, in obese and nonobese adults with OSA before and following positive airway pressure (PAP) treatment. Methods: A total of 206 adults newly diagnosed with OSA with an apnea-hypopnea index (AHI) of 15-75 events/hour and 53 controls with AHI <10 were studied. Waist circumference was used to classify participants as obese and nonobese. Bilateral common carotid artery B-mode ultrasound was performed at baseline to assess IMT, arterial diameter, arterial-wall mass, and circumferential wall stress. Measurements were repeated in 118 participants with OSA who completed a 4-month PAP treatment and had an average daily use over that period of ≥4 hours/day. Results: No significant differences in carotid IMT, diameter, or arterial-wall mass were present at baseline between participants with OSA and controls stratified by waist circumference, after adjusting for other cardiovascular risk factors. In participants with OSA, who had adequate PAP adherence over the 4-month treatment, carotid artery diameter significantly increased (mean change [95% confidence interval] = 0.13 [0.06, 0.20] mm; p = .0004), but no significant changes in carotid IMT, arterial-wall mass, and circumferential stress were observed in obese and nonobese participants. Conclusions: Regardless of obesity status, carotid IMT is not increased in adults with moderate to severe OSA versus controls and does not change following 4 months of PAP treatment.