Nocturnal Hypoxemia Increases Afib Risk in Obstructive Sleep Apnea

OSA obstructive sleep apnea illustration
Severe nocturnal hypoxemia was associated with a greater risk for atrial fibrillation vs milder or no hypoxemia.

In patients with suspected obstructive sleep apnea (OSA), nocturnal hypoxemia increased the risk for incident hospitalized atrial fibrillation (AF), according to a study published in CHEST.

A total of 8256 adults without arrhythmia who had been diagnosed with or suspected of having OSA and were referred to an academic hospital in Ontario between1994 and 2010 for a diagnostic sleep study were included. Using Cox regression analyses, researchers evaluated associations between the severity of OSA, as defined by the apnea-hypopnea index (AHI) and the degree of nocturnal hypoxemia, with incident hospitalized AF. Up to >30% of sleep time with oxygen saturation <90% defined severe nocturnal hypoxemia. Time from enrollment to first hospital admission for AF or atrial flutter comprised the primary outcome. The International Classification of Diseases-9 (427.3) and International Classification of Diseases-10 (I48) codes identified AF in this study.

During a median 10-year follow-up (interquartile range, 7-13 years), a total of 173 participants met the primary outcome. Compared with no OSA (AHI <5), patients with severe OSA (AHI >30) had an increased risk for AF (hazard ratio [HR], 2.64; 95% CI, 1.67-1.41). In addition, severe nocturnal hypoxemia was associated with a greater AF risk vs milder or no hypoxemia (HR, 4.76; 95% CI, 3.30-6.87).

In the analysis adjusted for age, sex, alcohol consumption, prior congestive heart failure, chronic obstructive pulmonary disease, pulmonary embolism, and smoking status, the association between AHI >30 and incident AF was significant (HR, 1.29; 95% CI, 0.79-2.11). The significant association between severe nocturnal hypoxemia and AF persisted (HR, 1.77; 95% CI, 1.15-2.74).

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Findings from this study may be limited in generalizability because only adults from a single Canadian center were included in the analysis.

“These findings support a relationship between OSA, chronic nocturnal hypoxemia, and the development of [AF], and may be used to identify those patients with OSA who are at greatest risk [for AF] developing,” the researchers concluded.


Kendzerska T, Gershon A, Atzema C, et al. Sleep apnea increases the risk of new hospitalized atrial fibrillation: a historical cohort study [published online September 19, 2018]. CHEST. doi:10.1016/j.chest.2018.08.1075