Effects of combined morbid insomnia and sleep apnea on long-term cardiovascular risk and all-cause mortality in elderly patients: a prospective cohort study

Purpose It is reported that insomnia and obstructive sleep apnea (OSA) increase the incidence of adverse cardiovascular events. The aim of this study was to analyze the risk of cardiovascular disease and mortality in elderly patients with comorbid insomnia and obstructive sleep apnea (COMISA). Methods We included 868 elderly patients with OSA who underwent sleep monitoring at a multicenter sleep room from January 2015 to October 2017. We collected demographic data, clinical features, medical history, sleep parameters, and laboratory findings. Cox proportional hazards analysis was used to identify the relationship between COMISA and adverse cardiovascular events and all-cause mortality. Results There were 181 elderly patients with COMISA. The median follow-up was 43 months, during which we observed major adverse cardiac events (MACE) in 90 patients. The Kaplan-Meier survival curve indicated a significant relationship between COMISA and MACE (P-log Rank < 0.001). Multivariate Cox regression analysis showed that COMISA increased the incidence of MACE (HR = 2.328, 95% CI: 1.349-4.018, P = 0.002), hospitalization for unstable angina (HR = 2.915, 95% CI: 1.397-6.081, P = 0.004), and the combination of all events (HR = 2.301, 95% CI: 1.393-3.803, P = 0.001). However, there were no significant differences in cardiovascular death, all-cause mortality, myocardial infarction, or hospitalized heart failure in patients with COMISA (P > 0.05). Subgroup analyses showed that among COMISA patients, male sex (HR = 2.800, 95% CI: 1.458-5.377, P = 0.002), age < 70 years (HR = 4.050, 95% CI: 2.022-8.115, P < 0.001), and overweight and obesity (HR = 2.482, 95% CI: 1.383-4.453, P = 0.002) were associated with a higher risk of MACE. Conclusions Our results showed that COMISA increased the risk of MACE, unstable angina, and the compound occurrence of all events. Male, overweight or obese COMISA patients under 70 years of age have an increased risk of MACE.