All-cause mortality and obstructive sleep apnea severity revisited

Area of Science:

• Sleep Medicine
• Cardiovascular Health
• Public Health

Background:

• Obstructive sleep apnea syndrome (OSAS) affects millions globally and is linked to hypertension, coronary artery disease, and stroke.
• The precise association between OSAS severity and all-cause mortality remains unclear.
• A comprehensive analysis of a large patient cohort is needed to quantify this risk.

Purpose of the Study:

• To investigate the association between obstructive sleep apnea syndrome severity and all-cause mortality.
• To identify specific sleep study metrics that correlate with mortality risk.
• To analyze these associations across different age groups.

Main Methods:

• A large-scale database study involving over 77,000 patients who underwent validated, portable sleep studies.
• Patients were matched to the Social Security Death File to determine all-cause mortality.
• Survival analysis with multivariate Cox proportional hazards regression was used to correlate OSAS severity and confounding factors with mortality.

Main Results:

• Increasing age, body mass index, and male sex were associated with increased all-cause mortality.
• The Epworth sleepiness score also showed a significant association with mortality.
• While the Apnea-Hypopnea Index (AHI) was not associated with mortality overall, specific metrics like the desaturation index, apnea index, and AHI were significantly linked to mortality in patients younger than 50 years.

Conclusions:

• Increasing OSAS severity, measured by AHI, apnea index, and desaturation index, is independently associated with modestly increased all-cause mortality.
• This association is particularly evident in patients younger than 50 years after adjusting for major confounding factors.
• In older patients (>50 years), age, sex, and BMI were the dominant factors associated with mortality.