Clinical Characteristics are Not Significant Predictors of Advanced Obstructive Sleep Apnea in the Severely Obese

Abstract

Introduction: Obstructive Sleep Apnea (OSA), present in 30-93% of bariatric patients, is an independent predictor of post-bariatric surgery complications. Universal screening with Polysomnography (PSG), the gold standard test for OSA, would be difficult to access and costly to perform. The purpose of this study was to identify clinically important, statistically significant predictors of moderate-to-severe OSA in a bariatric population that would enable providers to stratify or prioritize patients needing PSG. Methods: A cross-sectional study was performed in patients referred for clinical suspicion of OSA. All patients underwent PSG. From a list of potential covariates deemed clinically important, multivariable binary logistic regression was used to identify statistically significant predictors (p<0.05) of moderate-to-severe OSA. Subjects were recruited from a bariatric specialty program in Edmonton, Alberta, with a central, region-wide, single-point-ofaccess referral system. Results: Of 169 patients undergoing PSG, 161 (95.3%) had complete data. Mean age was 48.7 ± 9.1 years, 45(28%) were men, mean body mass index (BMI) was 49.5 ± 9.7 kg/m2. 96(60%) patients had moderate-to-severe OSA and the mean Apnea-Hypopnea Index (AHI) was 27.0 ± 27.3. The strongest predictors of OSA were neck circumference (OR 1.08; 95% CI 0.99-1.18) and hypertension (OR 1.95, 95% CI 0.93-4.09). However, no variable reached statistical significance. Conclusion: Despite a model adequately powered to identify 16-32 statistically significant predictors, none was found. Given the high prevalence of OSA in patients undergoing bariatric care, the lack of identifiable predictors mandates that objective sleep testing be performed in all patients clinically suspected to have OSA.