LAUSR

Background: We conducted meta-analyses to identify relationships between obstructive sleep apnea (OSA) severity, muscle sympathetic nerve activity (MSNA), and blood pressure (BP). We quantified the effect of OSA treatment on MSNA. Methods: Structured searches of electronic databases were performed until June 2021. All observational designs (except reviews) were included: population (individuals with OSA); exposures (OSA diagnosis and direct measures of MSNA); comparator (individuals without OSA or different severity of OSA); outcomes (MSNA, BP, and heart rate). Results: Fifty-six studies (N=1872) were included. MSNA burst frequency was higher in OSA (27 studies; n=542) versus controls (n=488; mean differences [MDs], +15.95 bursts/min [95% CI, 12.6–17.6 bursts/min]; I2=86%). As was burst incidence (20 studies; n=357 OSA, n=312 Controls; MD, +22.23 bursts/100 hbs [95% CI, 18.49–25.97 bursts/100 hbs]; I2=67%). Meta-regressions indicated relationships between MSNA and OSA severity (burst frequency, R2=0.489; P<0.001; burst incidence, R2=0.573; P<0.001). MSNA burst frequency was related to systolic pressure (R2=0.308; P=0.016). OSA treatment with continuous positive airway pressure reduced MSNA burst frequency (MD, 11.91 bursts/min [95% CI, 9.36–14.47 bursts/min] I2=15%) and systolic (n=49; MD, 10.3 mm Hg [95% CI, 3.5–17.2 mm Hg]; I2=42%) and diastolic (MD, 6.9 mm Hg [95% CI, 2.3–11.6 mm Hg]; I2=37%) BP. Conclusions: MSNA is higher in individuals with OSA and related to severity. This sympathoexcitation is also related to BP in patients with OSA. Treatment effectively reduces MSNA and BP, but limited data prevents an assessment of the link between these reductions. These data are clinically important for understanding cardiovascular disease risk in patients with OSA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: CRD42021285159.