The correlation between frailty index and incidence, mortality in obstructive sleep apnea: Evidence from NHANES

The emergence of obstructive sleep apnea (OSA) is marked by a growing trend towards younger individuals, while its developmental trajectory remains shrouded in uncertainty, accompanied by intricate prognostic implications. While frailty and sleep problems often coexist, the relationship between them remains unclear. Hence, this study aims to utilize the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2008 to analyze and explore the relationship between the level of frailty index (FI) and the risk of OSA incidence and survival outcomes.

Specialized weighted complex survey design analysis software was employed for data analysis. Multivariate logistic regression models and restricted cubic splines (RCS) were utilized to assess the association between FI and OSA incidence in all participants. Additionally, a Cox proportional hazards model was established to estimate the association between FI and the hazard ratios (HRs) for all-cause mortality and cardiovascular disease (CVD) mortality.

A total of 8524 participants were included in this study. Compared to the Non-frail group (FI ≤ 0.1), OSA risk increased with higher FI levels. In Model 3, adjusted for multiple covariates, the Pro-frail group (0.1 0.3) [OR = 2.32, 95 % CI (1.55, 3.48)] exhibited an average 31 %, 62 %, and 132 % increase in OSA risk, respectively. RCS results demonstrated a nonlinear dose-response relationship between OSA risk and FI levels, with an increasing trend (P = 0.004). The Cox model indicated that, except for the Pro-frail group, OSA-related mortality risk also increased with higher FI levels, with a more pronounced effect on CVD-related mortality.

This study supports the hypothesis that FI may be associated with an increased risk of OSA, with a higher emphasis on OSA-related mortality risk in Mildly frail and Moderately/Severely frail populations.