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).

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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