Association of Homocysteine and Risks of Long-Term Cardiovascular Events and All-Cause Death among Older Patients with Obstructive Sleep Apnea: A Prospective Study

Objectives This study aimed to assess whether raised baseline plasma tHcy concentrations increased the risks of major adverse cardiovascular events (MACE) and all-cause death outcomes in older patients with obstructive sleep apnea (OSA). Design A multicenter, prospective, observational study. Setting Beijing, Shandong Province, Gansu Province of China. Participants A total of 1, 290 OSA patients aged 60 to 96 years from sleep centers of six hospitals in China consecutively recruited between January 2015 and October 2017. Measurements Cox proportional models assessed the association between tHcy and the risk of new-onset all events among Chinese older OSA patients. Results The final analysis (60.1% male; median age, 66 years) used data from 1, 100 subjects during a median follow-up of 42 months, a total of 105 (9.5%) patients developed MACE and 42 (3.8%) patients died. Multivariable Cox regression analysis showed higher adjusted hazard ratios (aHRs) of MACE, myocardial infarction (MI), hospitalization for unstable angina, and composite of all events with tHcy levels in the 4th quartile (HR=5.93, 95% CI: 2.79–12.59; HR=4.72, 95% CI:1.36–4.61; HR=4.26, 95% CI:1.62–5.71; HR=4.17, 95% CI:2.23–7.81) and the 3rd quartile (HR=3.79, 95% CI:1.76–8.20; HR=3.65, 95% CI:1.04–2.98; HR=2.75, 95% CI:1.08–3.76; HR=2.51, 95% CI:1.31–4.83) compared to reference tHcy levels in quartile 1, respectively, while the aHRs (95% CIs) of all-cause death showed significantly higher only in the highest tHcy level quartile than in the lowest quartile (HR=3.20, 95% CI=1.16–8.84, P=0.025) with no significant differences in risks of cardiovascular death and hospitalisation for heart failure among groups (P>0.05). Conclusions tHcy, a marker of prognosis for older OSA patients, was significantly associated with the increased risk of MACE and all-cause death in this population independent of BMI, smoking status, and other potential risk factors, but not all clinical components events of MACE. New therapeutic approaches for older patients with OSA should mitigate tHcy-associated risks of MACE, and even all-cause death.