Sudden death in individuals with obstructive sleep apnoea: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 34108135 · doi:10.1136/bmjresp-2020-000656
What was done
Researchers conducted a systematic review and meta-analysis across MEDLINE, Cochrane Library, Scopus, and Joanna Briggs Institute databases from inception through January 1, 2020. They included observational studies evaluating sudden death and cardiovascular mortality in individuals with and without obstructive sleep apnea. Study quality was evaluated using the Newcastle-Ottawa Scale, and random-effects models were used to pool risk ratios with 95% confidence intervals.
What was found
Twenty-two observational studies comprising 42,099 participants (mean age 62 years, 64% men) were analyzed. Obstructive sleep apnea was significantly associated with all-cause sudden death (RR 1.74, 95% CI 1.44 to 2.10, I2 = 72%) and cardiovascular mortality (RR 1.94, 95% CI 1.39 to 2.70, I2 = 32%). A dose-response relationship by severity was present (p for interaction = 0.05): mild apnea RR 1.16 (95% CI 0.70 to 1.93), moderate RR 1.72 (95% CI 1.11 to 2.67), and severe RR 2.87 (95% CI 1.70 to 4.85). Meta-regression identified older age as a significant contributing factor.
Why it matters
This review demonstrates that obstructive sleep apnea is associated with a near doubling of cardiovascular mortality risk, with the hazard scaling directly with disease severity and age.
Limits
The analysis is restricted to observational studies, precluding causal inference. Substantial statistical heterogeneity was present for all-cause sudden death (I2 = 72%). The abstract does not report whether individual studies adjusted for critical confounders such as obesity and cardiovascular comorbidities, nor whether sleep apnea treatment status was controlled for.
Cited by
- supports Sleep apnea is strongly associated with increased long-term mortality risk, impaired cognitive function, mood dysregulation, reduced athletic performance and recovery, and poor metabolic health.