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. / Sensibilidad de un modelo secuencial basado en cuestionario (STOP-Bang vs. Dixon) y pulsioximetría nocturna para el screening de apnea obstructiva del sueño en pacientes obesos mórbidos candidatos a cirugía bariátrica.

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.

Epigenetics dysfunction in morbid obesity with or without obstructive sleep apnoea: the EPIMOOSA study.

BACKGROUND: Obstructive sleep apnoea (OSA) and morbid obesity (MO), defined by a body mass index ≥35 kg/m2, are two closely related conditions. Recent studies suggest that circulating microRNA (miRNA) plays a potential role in the physiopathology of both conditions. To date, circulating miRNA expression has been studied separately in both conditions, but never jointly. The primary treatment of OSA is continuous positive airway pressure (CPAP), whereas bariatric surgery (BS) is the treatment of choice for MO. We have thus initiated the Epigenetics modification in Morbid Obesity and Obstructive Sleep Apnoea (EPIMOOSA) study (ClinicalTrials.gov identifier: NCT03995836). METHODS/DESIGN: EPIMOOSA is a prospective non-interventional cohort study aiming to recruit 45 MO patients who are candidates for BS. Three groups will be formed: MO without OSA, MO with OSA without CPAP and MO with OSA and CPAP. All of them will be followed up in 4 visits: baseline, 6 months prior to BS and 3, 6 and 12 months post-BS. At baseline, OSA status will be assessed by home sleep polygraphy (HSP), and CPAP will be adopted according to national guidelines. A specific standardized questionnaire (including medical conditions and AOS-related symptoms) and anthropometrical examination will be performed at each visit. Blood samples will be obtained at each visit for immediate standard biochemistry, haematology and inflammatory cytokines. For bio-banking, serum, plasma, and circulating exosomes will also be obtained. Twenty-four hours of blood pressure and electrocardiogram (ECG) Holter monitoring will be performed at all visits. A new HSP will be performed at the last visit. Finally, the three groups will be sex- and age- matched with participants in the EPIOSA study, an ongoing study aimed at understanding epigenetic changes in non-obese OSA patients. DISCUSSION: EPIMOOSA will evaluate changes in circulating miRNA in MO with or without OSA for the first time. In addition, EPIMOOSA will be able to elucidate the influence of OSA in MO patients and how specific and combined treatments alter miRNA expression.