Association of Metabolic Syndrome With Long-Term Cardiovascular Risks and All-Cause Mortality in Elderly Patients With Obstructive Sleep Apnea

Abstract

BackgroundEvidence suggests that an increased risk of major adverse cardiac events (MACE) and all-cause mortality is associated with obstructive sleep apnea (OSA), particularly in the elderly. Metabolic syndrome (MetS) increases cardiovascular risk in the general population; however, less is known about its influence in patients with OSA. We aimed to assess whether MetS affected the risk of MACE and all-cause mortality in elderly patients with OSA.MethodsFrom January 2015 to October 2017, 1,157 patients with OSA, aged ≥60 years, no myocardial infarction (MI), and hospitalization for unstable angina or heart failure were enrolled at baseline and were followed up prospectively. OSA is defined as an apnea-hypopnea index of ≥5 events per hour, as recorded by polysomnography. Patients were classified on the basis of the presence of MetS, according to the definition of the National Cholesterol Education Program (NCEP). Incidence rates were expressed as cumulative incidence. Cox proportional hazards analysis was used to estimate the risk of all events. The primary outcomes were MACE, which included cardiovascular death, MI, and hospitalization for unstable angina or heart failure. Secondary outcomes were all-cause mortality, components of MACE, and a composite of all events.ResultsMetS was present in 703 out of 1,157 (60.8%) elderly patients with OSA. During the median follow-up of 42 months, 119 (10.3%) patients experienced MACE. MetS conferred a cumulative incidence of MACE in elderly patients with OSA (log-rank, P < 0.001). In addition, there was a trend for MACE incidence risk to gradually increase in individuals with ≥3 MetS components (P = 0.045). Multivariate analysis showed that MetS was associated with an incidence risk for MACE [adjusted hazard ratio (aHR), 1.86; 95% confidence interval (CI), 1.17–2.96; P = 0.009], a composite of all events (aHR, 1.54; 95% CI, 1.03–2.32; P = 0.036), and hospitalization for unstable angina (aHR, 2.01; 95% CI, 1.04–3.90; P = 0.039). No significant differences in the risk of all-cause mortality and other components of MACE between patients with and without MetS (P > 0.05). Subgroup analysis demonstrated that males (aHR, 2.23; 95% CI, 1.28–3.91, P = 0.05), individuals aged <70 years (aHR, 2.36; 95% CI, 1.27–4.39, P = 0.006), overweight and obese individuals (aHR, 2.32; 95% CI, 1.34–4.01, P = 0.003), and those with moderate-severe OSA (aHR, 1.81;95% CI: 1.05–3.12, P = 0.032) and concomitant MetS were at a higher risk for MACE.ConclusionMetS is common in elderly patients with OSA in the absence of MI, hospitalization for unstable angina or heart failure. Further, it confers an independent, increased risk of MACE, a composite of all events, and hospitalization for unstable angina. Overweight and obese males, aged <70 years with moderate-severe OSA combined with MetS presented a significantly higher MACE risk.

Associations between abdominal obesity and the risk of stroke in Chinese older patients with obstructive sleep apnea: Is there an obesity paradox?

“…Polysomnography is a gold standard for diagnosis of OSA and all participants completed standardized full nocturnal PSG testing (from 21:00 to 07:00 the next day) in a sleep laboratory within 7 days after admission ( Liu et al, 2022 ). Participants were asked to strictly abstain from consuming caffeine, sedatives, and hypnotic drugs in the 24 h preceding the full-night sleep study.…”

“…Participants were asked to strictly abstain from consuming caffeine, sedatives, and hypnotic drugs in the 24 h preceding the full-night sleep study. The sleep analysis was performed on-site using laboratory-based PSG equipment (Compumedics, Melbourne, VIC, Australia) and standard methods that have been described previously ( Liu et al, 2022 ). All essential parameters of the sleep tests with specific respiration events were recorded and included electroencephalography, electrooculography, electrocardiography, nasal and oral airflow, thoracic/abdominal movements, pulse oxygen saturation, tracheal microphone for snoring, body position, and sleep parameters, such as the AHI, oxygen desaturation indices (ODI), mean oxygen saturation (MSpO 2 ), lowest oxygen saturation (LSpO 2 ), and total sleep time (TST).…”

The Metabolic Syndrome, a Human Disease

“…Sleep apnea and its consequences on adrenergic signaling have also been related to AHT [330] and other cardiovascular effects [331,332]. The induction of atrial fibrillation is a known path for these interactions [301,333,334].…”

“…Its epidemiology [1010] and consequences are, however, better known, with a close relationship with the irregular discharge of catecholamines as response to the extended/repeated periods of hypoxia [877]. This situation alters the heart's rhythm [333] and elicits cardiovascular consequences [332], in addition to the problems caused by disordered sleep [1011] and respiratory complications [1012]. These problems have a multiplying effect when translated to their effect on behavior [1013].…”

Cardiovascular Risk Factors in China

“…Compared with non-MS controls, the HR for CVD was 1.84 (95% CI: 1.31-2.57) in the MS onset age < 45 years group, 1.67 (95% CI: 1.42-1.95) for the 45-54 years group, 1.36 (95% CI: 1.18-1.58) for the 55-64 years group, and 1.28 (95% CI: 1.10-1.50) for the ≥ 65 years group, respectively. [141] A total of 1,157 patients with obstructive sleep apnea (OSA), aged ≥ 60 years, no myocardial infarction, and hospitalization for unstable angina or heart failure at baseline were enrolled. During the median follow-up of 42 months, MS was present in 703 out of 1,157 (60.8%) elderly patients with OSA.…”