Sleep apnea increases the risk of new hospitalized atrial fibrillation: a historical cohort study

Objectives — This study examined the relationship between newly diagnosed OSA and incident hospitalized atrial fibrillation (AF) over the subsequent 10 years in a large arrhythmia-free cohort.

Methods — Adults referred between 1994 and 2010 to a large academic hospital with suspected OSA who were arrhythmia-free at the time of first diagnostic sleep study were included. Clinical data were linked to provincial health administrative data to define outcome. We used Cox regressions to investigate the relationship between OSA severity as measured by the apnea-hypopnea index (AHI) and degree of nocturnal hypoxemia, and incident hospitalized AF.

Results — In total, 8,256 subjects were included in this study. Their median age was 47 years, 62% were men, 28% had an AHI > 30 events per hour, and 6% spent >30% of sleep time with oxygen saturation < 90%. Over a median follow-up of 10 years (interquartile range, 7-13 years), 173 participants (2.1%) were hospitalized with AF. Controlling for age, sex, alcohol consumption, smoking status, prior heart failure, COPD, and pulmonary embolism, nocturnal hypoxemia (but not AHI) was a significant predictor of incident AF: hazard ratio, 2.47 (95% CI, 1.64-3.71). After further controlling for BMI and hypertension, this association was attenuated but remained significant (hazard ration, 1.77 [95% CI, 1.15-2.74]).

Conclusions — In a large arrhythmia-free clinical cohort with suspected OSA, nocturnal hypoxemia was independently associated with a 77% increased hazard of incident hospitalized AF. These findings further support a relationship between OSA, nocturnal hypoxemia, and new-onset AF, and they may be used to enhance AF prevention in patients with OSA and severe nocturnal hypoxemia.