P129 Neck circumference versus body mass index to predict moderate to severe obstructive sleep apnoea

INTRODUCTION: Neck circumference (NC) and body mass index (BMI) are both markers of obesity and established parameters in clinical models for the prediction of obstructive sleep apnoea (OSA). It is unclear if one parameter is superior for the prediction of OSA severity or if the addition of both parameters significantly enhances the accuracy of the clinical model. In this study, we evaluated the performance of NC and BMI as predictors for moderate to severe OSA (AHI≥15) when adjusted for age and male gender. METHODS: A retrospective chart review of all diagnostic sleep studies (SS) conducted from November 2017 to October 2018 was performed. All SS which were reported as normal and all SS with a diagnosis of OSA were included. Three multiple regression models were constructed with AHI≥15 as the dependent variable and the following independent variables: NC + Age + Gender (NAG), BMI + Age + Gender (BAG), and BMI + NC + Age + Gender (BNAG). The Akaike information criterion (AIC) was used for model comparison. A model that was more than 2 AIC units lower was considered to be the superior model. RESULTS: 112 SS had AHI<15 and 193 SS had AHI≥15. The AIC for NAG, BAG and BNAG models were 333.9, 343.8 and 334.7 respectively. DISCUSSION: The NAG model had the lowest AIC. NC was superior to BMI for the prediction of AHI≥15. The performance of the clinical model incorporating both NC and BMI was not significantly different from the model incorporating only NC.