The Sleep Apnea-Specific Hypoxic Burden Predicts Incident Heart Failure

Background

Heart failure (HF) is a leading cause of morbidity and mortality and although it is linked to sleep apnea, which physiological stressors most strongly associate with incident disease is unclear. We tested whether sleep apnea-specific hypoxic burden (SASHB) predicts incident HF in two independent cohort studies.

Research Question

In comparison with apnea-hypopnea index (AHI), how does sleep apnea-specific hypoxic burden predict incident HF?

Study Design and Methods

The samples were derived from two cohort studies: The Sleep Heart Health Study (SHHS), which included 4,881 middle-aged and older adults (54.4% women), age 63.6 ± 11.1 years; and the Outcomes of Sleep Disorders in Older Men (MrOS), which included 2,653 men, age 76.2 ± 5.4 years. We computed SASHB as the sleep apnea-specific area under the desaturation curve from pre-event baseline. We used Cox models for incident HF to estimate the adjusted hazard ratios (HRs) for natural log-transformed SASHB and AHI adjusting for multiple confounders.

Results

The SASHB predicted incident HF in men in both cohorts, whereas AHI did not. Men in SHHS and MrOS had adjusted HRs (per 1SD increase in SASHB) of 1.18 (95% CI, 1.02-1.37) and 1.22 (95% CI, 1.02-1.45), respectively. Associations with SASHB were observed in men with both low and high AHI levels. Associations were not significant in women.

Interpretation

In men, the hypoxic burden of sleep apnea was associated with incident HF after accounting for demographic factors, smoking, and co-morbidities. The findings Suggest that quantification of an easily measured index of sleep apnea-related hypoxias may be useful for identifying individuals at risk for heart disease, while also suggesting targets for intervention.