Obstructive sleep apnea, preserved ratio impaired spirometry (PRISm), and all-cause mortality: a community-based prospective study

The association between obstructive sleep apnea (OSA) and preserved ratio impaired spirometry (PRISm) has not been well studied. This prospective cohort study enrolled 3408 adults aged 20-79 years without airflow obstruction. The median follow-up time was 11.8 years. Probable OSA (pOSA) was defined based on symptoms (snore, snort/stop breathing, sleepy) and was divided into a normal lung function group (FEV1 ≥ 80% predicted) and a PRISm group (FEV1 < 80% predicted) according to spirometry. Multivariable regression was used to analyze the association between pOSA and PRISm, and Cox regression and Kaplan-Meier analysis were used to assess the effects of pOSA alone, PRISm alone, and both on the risk of mortality. All analyses used survey weights. At baseline, 28.5% of participants presented with pOSA, and 11.4% had PRISm. Multivariable analysis showed an independent association between pOSA and PRISm (adjusted OR = 1.40, 95% CI 1.01-1.94, p = 0.04). Individuals with comorbid pOSA and PRISm had the highest risk of death (adjusted HR = 2.34, 95% CI 1.55-3.55) compared with individuals with PRISm alone (adjusted HR = 1.78, 95% CI 1.3-2.44), while individuals with pOSA alone were not significantly associated with death (adjusted p = 0.893). Kaplan-Meier analysis confirmed significant survival differences between the groups (p < 0.0001). Our results show that individuals with suspected OSA are associated with a higher prevalence of PRISm and individuals with comorbid OSA and PRISm have a higher risk of all-cause death. Although the limitations of the observational study do not allow us to determine causality, it emphasizes that the association between OSA and PRISm deserves further in-depth study.