The association between obstructive sleep apnea of varying severity and cardiovascular risk: a systematic review and meta-analysis
C Niu, J W Dong, P Y Zhang, S Y Li, L J ZhangAbstract
Background
Obstructive sleep apnea (OSA) is closely associated with cardiovascular diseases and mortality risk. The severity of OSA may have varying effects on cardiovascular health; however, current studies have not systematically assessed the relationship between different severities of OSA and cardiovascular diseases, cardiovascular mortality, and all-cause mortality. This study aims to investigate the impact of varying severities of OSA on cardiovascular diseases and mortality risk through a systematic review and meta-analysis.
Methods
Following the PRISMA guidelines, we conducted a systematic literature search of prospective cohort studies published from the establishment of the databases to December 2025, retrieved from PubMed, Web of Science, Cochrane Library, and Embase. Studies that examined the relationship between different severities of OSA and cardiovascular diseases, as well as mortality risks (cardiovascular mortality and all-cause mortality), were selected. A random-effects model was used to calculate hazard ratios (HR) and their 95% confidence intervals (CI), and heterogeneity and statistical significance were assessed.
Results
A total of 13 high-quality studies involving 29,618 patients were included. The results showed that varying severities of OSA were significantly associated with cardiovascular diseases and mortality risks:Mild OSA had a risk ratio for cardiovascular disease of 1.18 (95% CI: 0.97-1.43), which was not statistically significant.Moderate OSA had a risk ratio of 1.74 (95% CI: 1.21-2.50), significantly increasing the risk of hypertension, coronary artery disease, and other cardiovascular conditions. The risk of cardiovascular death was 1.61 (95% CI: 1.32-1.90), and the risk of all-cause mortality was 1.23 (95% CI: 1.02-1.49).Severe OSA had a risk ratio for cardiovascular disease of 2.22 (95% CI: 1.56-3.15), and both cardiovascular mortality (2.22, 95% CI: 1.56-3.15) and all-cause mortality (1.67, 95% CI: 1.38-2.06) were significantly increased.
Conclusions
The severity of OSA is significantly positively correlated with cardiovascular diseases, cardiovascular mortality, and all-cause mortality. Severe OSA patients face the most significant cardiovascular risk and should be prioritized for cardiovascular health management. Moderate OSA also presents a significant cardiovascular risk and requires regular assessment. Although mild OSA shows a weaker association with cardiovascular diseases, its potential risks should not be overlooked. The severity of OSA should be considered a critical factor in cardiovascular risk assessment.Study Selection FlowchartCharacteristics of Included Studies Char