Sensitivity of a sequential model based on a questionnaire (STOP-Bang vs Dixon) and nocturnal pulse oximetry for screening obstructive sleep apnea in patients with morbid obesity candidates for bariatric surgery.

Introduction: Obstructive sleep apnea (OSA) has a high incidence in patients with morbid obesity who are candidates for bariatric surgery (BS). Adequate screening would decrease the number of respiratory polygraphies (RPs).

Objective: To analyze the value of a sequential model consisting of a questionnaire (modified Dixon [DXM] vs STOP-Bang) and nocturnal pulse oximetry in patients who were candidates for BS.

Methods: A prospective study was conducted from July 1, 2014 to July 1, 2015 on candidates for BS, excluding those who have already undergone RP.

Variables: questionnaires (Epworth, STOP-Bang, and DXM), anthropometric measurements, RP, and blood and gas tests. The sample was divided into patients with no or mild OSA (no OSA) and those with moderate to severe OSA (AHI>15).

Results: A total of 70 patients were analyzed, 46 (65.7%) of them females. Moderate to severe OSA was diagnosed in 26 (37.1%) patients. STOP-Bang and DXM were compared using ROC curves, and greater area under the curve (AUC) was found for the latter (0.873 [0.74 -0.930] vs 0.781 [0.673-0.888]). STOP-Bang had greater sensitivity, 100%, as compared to 73.1% for DXM. ODI3% showed greater diagnostic yield (AUC=0.982 [0.970-1]). Use of the sequential model with STOP-Bang>3, DXM>5, and DXM>3 would have avoided 41 (58.5%), 50 (71.4%), and 41 (58.5%) RPs and 0, 7 (10%), and 0 false negatives, respectively.

Conclusion: Use of a sequential model based on the STOP-Bang and nocturnal pulse oximetry is a useful tool for screening OSA in patients with morbid obesity candidates for BS, decreasing the number of RPs.