Hypoxic burden in men with obstructive sleep apnoea foretells heart failure

The hypoxic burden associated with obstructive sleep apnoea (OSA) may predict the development of heart failure (HF) in men, a study has found.

The analysis included 4,881 middle-aged and older adults (mean age, 63.6 years; 54.4 percent female) from the Sleep Heart Health Study (SHHS) and 2,653 men (mean age, 76.2±5.4 years) from the Outcomes of Sleep Disorders in Older Men (MrOS). Overall, 7,534 individuals (20.1 percent) from both cohorts had moderate-to-severe OSA (apnoea-hypopnea index [AHI] ≥15).

Researchers computed the Sleep Apnea-Specific Hypoxic Burden (SASHB) as the sleep apnoea-specific area under the desaturation curve from pre-event baseline.

In the SHHS cohort, men had significantly higher mean SASHB (62.0 vs 37.0 %minute/hour; p<0.001) and AHI (11.0 vs 6.17 events/hour; p<0.001) compared with women. Over a mean follow-up of 10.4 years, 543 individuals developed HF, with the rate higher in men (11.9 vs 9.2 per 1,000 person-years for women) and increasing accordingly with higher AHI and SASHB.

In the MrOS cohort, 145 men developed HF over a mean follow-up of 8.8 years. The resulting incident rate was 6.05 per 1,000 person-years of follow-up, and this rose with increasing AHI and SASHB in the same way as in the SHHS cohort.

Multivariable Cox proportional hazard analysis revealed that SASHB predicted incident HF in men in both cohorts, whereas AHI did not. The resulting adjusted hazard ratios for HF per 1-SD increase in SASHB were 1.18 (95 percent confidence interval [CI, 1.02–1.37) in the SHHS cohort and 1.22 (95 percent CI, 1.02–1.45) in the MrOS cohort.

The association between HF and SASHB was observed in men with either low or high AHI levels. This was not seen in women.

“The findings suggest that quantification of an easily measured index of sleep apnoea-related hypoxias may be useful for identifying individuals at risk for heart disease while also suggesting targets for intervention,” the researchers said.