Screening for obstructive sleep apnea/hypopnea syndrome: Subjective and objective factors

Abstract

Objectives: To determine the sensitivity and specificity of the Berlin Questionnaire and the Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS) score for individually predicting a diagnosis of OSAHS, and to propose a method for OSAHS screening incorporating objective and subjective factors. Study Design: Cross-sectional survey. Setting: Tertiary care center. Methods: Charts were reviewed from 223 consecutive patients for whom complete data regarding the Berlin questionnaire, OSAHS score (Friedman tongue position + tonsil size + body mass index grade), Epworth Sleepiness Scale, and visual analog scale for snoring were obtained prior to polysomnography (PSG). Sensitivity and specificity were determined for the Berlin questionnaire and OSAHS score for predicting an apnea hypopnea index (AHI) ≥ 5. Patient data were subjected to multivariate stepwise discriminant analysis and used to construct a screening system based on the Fisher's linear classification equation. Results were cross-validated by PSG findings. Results: In predicting an AHI ≥ 5, the sensitivity and specificity, respectively, were 0.615 and 0.226 for the Berlin questionnaire, 0.863 and 0.468 for OSAHS score, and 0.82 and 0.834 for our predictive equation. When applied case-wise to the study population, this equation correctly predicted 82.5 percent of diagnoses. Accuracy was highest for severe OSAHS (87.4%) and lowest for mild disease (77.0%). Sensitivity was lowest for mild OSAHS (0.50). Conclusions: Neither the Berlin questionnaire nor the OSAHS score alone was both highly sensitive and specific for diagnosing OSAHS. By incorporating subjective and objective metrics into a single predictive equation, sensitivity and specificity were maximized, and 82.5 percent of diagnoses were accurately predicted.