A decision rule for diagnostic testing in obstructive sleep apnea.
Obstructive sleep apnea (OSA) is traditionally diagnosed using overnight polysomnography. Decision rules may provide an alternative to polysomnography. A consecutive series of patients referred to a tertiary sleep center underwent prospective evaluation with the upper airway physical examination protocol, followed by determination of the respiratory disturbance index using a portable monitor. Seventy-five patients were evaluated with the upper airway physical examination protocol. Historic predictors included age, snoring, witnessed apneas, and hypertension. Physical examination-based predictors included body mass index, neck circumference, mandibular protrusion, thyro-rami distance, sterno-mental distance, sterno-mental displacement, thyro-mental displacement, cricomental space, pharyngeal grade, Sampsoon-Young classification, and over-bite. A decision rule was developed using three predictors: a cricomental space of 1.5 cm or less, a pharyngeal grade of more than II, and the presence of overbite. In patients with all three predictors (17%), the decision rule had a positive predictive value of 95% (95% confidence interval [CI], 75-100%) and a negative predictive value of 49% (95% CI, 35-63%). A cricomental space of more than 1.5 cm (27% of patients) excluded OSA (negative predictive value of 100%, 95% CI, 75-100%). Comparable performance was obtained in a validation sample of 50 patients referred for diagnostic testing. This decision rule provides a simple, reliable, and accurate method of identifying a subset patients with, and perhaps more importantly, without OSA.
Department of Medicine, University of Calgary, AB, Canada. tsai@ucalgary.ca
Willis H
WH
Tsai
John E
JE
Remmers
Rollin
R
Brant
W Ward
WW
Flemons
Jan
J
Davies
Colin
C
Macarthur
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000886:Anthropometry; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010614:Pharynx / Q000033:anatomy & histology / Q000502:physiology; D010808:Physical Examination / Q000379:methods; D017286:Polysomnography / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology