PURPOSE: The use of screening OSA questionnaires and overnight oximetry in conjunction with airflow monitoring is used for screening OSA prior to expensive in-lab polysomnography. The accuracy of the STOP-BANG OSA screening questionnaire and the in-home ApneaLink™ test in the clinical setting is not well established despite their extensive use in clinical practice. This study was done to evaluate the positive predictive value of the STOP-BANG screening questionnaire and the ApneaLink™ test when compared to the gold standard of attended polysomnography.
METHODS: Medical records of patients that underwent ApneaLink™ testing (AL) and an attended polysomnography (PSG) were reviewed. Only those patients that had both studies done within a 6 month window were analyzed. Charts were reviewed for the following: 1. STOP-BANG Questionnaire elements: Presence of snoring, male sex, age>50, hypertension, neck circumference >40 cm, tiredness/fatigue, witnessed apneas, and BMI > 35 kg/m2. The STOP-BANG Questionnaire has shown in prior studies an association with OSA risk. 2. AL testing results: The apnea-hypopnea index (AL-AHI) reported by automated scoring was used. 3. PSG data from an AASM-accredited sleep facility Categories of AHI abnormalities obtained during PSG and were compared to different combinations of AL-AHI and STOP-BANG total scores and STOP-BANG elements.
RESULTS: 110 patient charts were reviewed, sufficient information was available for 75 (68%) patients. The mean age of the subjects was 60 years, 44% were male, and the mean BMI was 34 kg/m2. The AL-AHI demonstrated a sensitivity and specificity at a PSG AHI cutoff ≥ 15 of 67% and 78% respectively. The total STOP-BANG score ≥ 4 at PSG AHI cutoff ≥15 (moderate-severe sleep apnea) had a sensitivity and specificity of 85% and 44% respectively. When evaluating individual elements of STOP-BANG combined with AHI ≥15, sensitivities and specificities were noted in 3 elements as follows: HTN 79% and 89%, Neck size 74%and 92% and male 75% and 93% respectively.
CONCLUSIONS: The AL-AHI or the Stop Bang questionnaire are not sensitive enough to use as screening tools. The combination of AL-AHI ≥ 15 and the presence of HTN, male, or neck size > 40cm results in a high sensitivity and specificity for the diagnosis of moderate to severe OSA.
CLINICAL IMPLICATIONS: The combination of AL test with 1 of 3 elements of the STOP-BANG Questionnaire (HTN, male, or neck size > 40cm) is a quick, inexpensive method of determining patients at risk for moderate to severe OSA.
DISCLOSURE: The following authors have nothing to disclose: Dixie Harris, Benjamin Sokolow, Krishna Sundar, Karl Ludwig
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