38 Copyright © 2020 The Korean Society of Sleep Medicine pISSN 2093-9175 / eISSN 2233-8853 ORIGINAL ARTICLE Background and ObjectiveaaTe conventional criteria for body-mass index (BMI > 35 kg/m 2 ) and neck circumference (NC > 40 cm) in the snoring, tiredness, observed apnea, high blood pres- sure, BMI, age, NC, and gender (STOP-Bang) Questionnaire may be too high to screen Korean ob- structive sleep apnea (OSA) patients properly. We hypothesized that using a modifed STOP-Bang Questionnaire with lower BMI and NC criteria may be more appropriate when screening South Korean patients with OSA. We aimed to evaluate the utility of the modifed STOP-Bang Question- naires and to compare it with that of conventional STOP or STOP-Bang Questionnaire. MethodsaaTis was a cross-sectional single-center study done at Kyung Hee University Hospital at Gangdong. Consecutive patients who underwent polysomnography and had done the STOP- Bang Questionnaire between November 2010 and December 2017 were reviewed. We used alterna- tive cut-of criteria for BMI as 30 kg/m 2 and for NC as 36.3 cm. ResultsaaA total of 778 patients was evaluated; 73.1% of them had some OSA [apnea-hypopnea index (AHI) > 5/hr] and 54.5% had moderate to severe OSA (AHI > 15/hr). Te area under the curve (AUC) of the modifed STOP-Bang was slightly larger than for the conventional STOP-Bang or STOP for having any OSA (AUC 0.787, 0.781, and 0.765, respectively) or for moderate to severe OSA (AUC 0.749, 0.747, and 0.721). Te conventional STOP-Bang Questionnaire with a cut-of score of 3 identifed all OSA and moderate to severe OSA patients with a sensitivity of 94.7% and 96.9%, re- spectively. Te modifed STOP-Bang showed improved sensitivity for any or moderate to severe OSA of 95.6% and 98.1%, respectively, with a decrease in exchange for lower specifcity. ConclusionsaaBecause of the high prevalence of undiagnosed OSA, the modifed STOP-Bang might be more appropriate in screening South Korean patients with OSA. Sleep Med Res 2020;11(1):38-43 Key Wordsaa STOP-Bang Questionnaire, Obstructive sleep apnea, Body mass index. INTRODUCTION Te STOP-Bang Questionnaire was frst developed in 2008 and validated for screening pa- tients for obstructive sleep apnea (OSA) surgery [1]. Te questionnaire includes eight dichot- omous items related to the clinical features of OSA: four subjective (STOP: snoring, tiredness, observed apnea, and high blood pressure) and four demographics items [Bang: body-mass in- dex (BMI), age, neck circumference (NC), and gender]. Te cut-of criteria of 3 for STOP-Bang is known to indicate a high risk of OSA, with sensitivity and specifcity of 83.6% and 56.4%, re- spectively [1]. Given its ease of use and high sensitivity, the STOP-Bang Questionnaire has been widely used in preoperative clinics, sleep clinics, the general population, and other special pop- ulations to detect patients at high risk of OSA [2]. https://doi.org/10.17241/smr.2020.00591 Usefulness of Using Alternative Body-Mass Index and Neck Circumference Criteria for STOP-Bang Questionnaire in Screening South Korean Obstructive Sleep Apnea Patients Jung-Ick Byun, MD, PhD 1,2 *, Dong-Ha Kim, MD 1 *, Jeong-Su Kim, MD 1 , Won Chul Shin, MD, PhD 1,2 1 Department of Neurology, Kyung Hee University Hospital at Gangdong, Seoul, Korea 2 Department of Neurology, School of Medicine, Kyunghee University, Seoul, Korea Received: May 23, 2020 Revised: June 11, 2020 Accepted: June 20, 2020 Correspondence Won Chul Shin, MD, PhD Department of Neurology, Kyung Hee University at Gangdong, 892 Dongnam-ro, Gangdong-gu, Seoul 05278, Korea Tel +82-2-440-6166 Fax +82-2-440-7242 E-mail shin1chul@gmail.com *Tese authors contributed equally to this work. ORCID Jung-Ick Byun https://orcid.org/0000-0002-6224-4575 Dong-Ha Kim https://orcid.org/0000-0003-1879-9976 Jeong-Su Kim https://orcid.org/0000-0002-2892-0365 Won-Chul Shin https://orcid.org/0000-0003-3044-9397 cc Tis is an Open Access article distributed un- der the terms of the Creative Commons Attribu- tion Non-Commercial License (https://creative- commons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.