NoSAS score and the 5-year risk of incident cerebrovascular disease: a retrospective cohort study

Obstructive sleep apnea (OSA) is a common but often underdiagnosed disorder linked to various adverse health outcomes, especially cerebrovascular events. This study aims to evaluate the utility of the NoSAS score in screening for high risk of cerebrovascular disease, facilitating early identification and improving clinical management of OSA in susceptible populations.

This retrospective study enrolled patients from two sleep centers who underwent sleep apnea monitoring between September 2016 and December 2019. Individuals with pre-existing cerebrovascular disease were excluded from the study. Follow-up data on 5-year incident cerebrovascular events were collected via medical records or telephone interviews. Cerebrovascular events were primarily identified based on patient self-report and available clinical documentation; systematic neuroimaging confirmation was not routinely available. Participants were categorized by NoSAS score into high-risk (≥8) and low-risk (<8) groups. Logistic regression was used to assess the association between NoSAS risk classification and cerebrovascular disease incidence, and Nelson-Aalen were used to compare compared cumulative risk between groups over the 5-year period.

A total of 1,348 participants with complete NoSAS score data who completed follow-up were included in the analysis. Among the 690 participants in the high-risk group, the 5-year incidence of cerebrovascular disease was 9.71%. In the adjusted model, the NoSAS high-risk group had a 1.8-fold increased risk of cerebrovascular disease compared to the low-risk group (OR: 1.85, 95% CI: 1.01∼3.38; p = 0.045). ESS-stratified analyses showed significant associations between NoSAS risk classifications and cerebrovascular disease in ESS scores ≤ 9.

The NoSAS high-risk group showed a higher incidence of cerebrovascular disease, which could be used as an independent predictor of the disease and may have higher predictive value in the high-risk group of non-sleepy OSA.