Diagnostic accuracy of overnight oximetry for the diagnosis of sleep-disordered breathing in atrial fibrillation patients

Background: Sleep-disordered breathing (SDB) is highly prevalent in patients with atrial fibrillation (AF) and its treatment can improve rhythm control. Polysomnography (PSG) is the gold standard for the diagnosis of SDB but its high cost and limited availability constrain its role as a standard SDB screening tool. We sought to assess the diagnostic utility of overnight oximetry in predicting SDB in AF patients.

Methods: We analyzed prospectively collected data on 439 patients with documented AF (62% paroxysmal AF) who underwent PSG. Overnight oximetry was used to determine the oxygen desaturation index (ODI, number of desaturation/h) by a novel automated computer algorithm. ODI was validated against PSG derived apnea-hypopnea index (AHI).

Results: The sample consisted of 69% men with a mean age of 59.9 ± 11.3 years and body mass index of 30 ± 5 kg/m². The median AHI was 9.5 [3.6-21.0]/h and the prevalence of moderate (AHI 15-29/h) and severe SDB (AHI ≥ 30/h) was 17.3% and 16.6% respectively. The ODI was able to detect moderate-to-severe SDB (AHI ≥ 15/h; area under the receiver-operating-characteristic curve (AUC): 0.951, 95% CI: 0.929-0.972) and severe SDB (AHI ≥ 30/h; 0.932, 95% CI: 0.895-0.968) with high diagnostic accuracy. An ODI cut-off of 4.1/h resulted in a 91% sensitivity and 83% specificity in discriminating between patients with and without AHI ≥ 15/h. An ODI of 7.6/h yielded a sensitivity and specificity for AHI ≥ 30/h of 89% and 83%, respectively.

Conclusions: ODI derived from a simple and low-cost overnight oximetry can be used as an accessible and reliable screening tool, particularly to rule out SDB.