Predicting Obstructive Sleep Apnea in Patients with Insomnia: A Comparative Study with Four Screening Instruments

Purpose: Obstructive sleep apnea (OSA) and insomnia are very prevalent disorders, especially in sleep-lab setting, and insomnia may be the presenting complaint of OSA. Here, we aimed to validate No-Apnea as screening tool for OSA in patients with self-reported insomnia complaints and to compare its performance with other models. Methods: This cross-sectional study involved evaluation of No-Apnea as well as STOP-Bang, NoSAS and Epworth Sleepiness Scale (ESS) in subjects with insomnia being evaluated with full in-lab polysomnography. Discrimination was assessed by area under the curve (AUC), while predictive parameters were calculated by contingency tables. OSA severity was classified based on the apnea/hypopnea index: ≥ 5.0/h as any OSA (OSA _≥5 ), ≥ 15.0/h as moderate/severe OSA (OSA _≥15 ), and ≥ 30.0/h as severe OSA (OSA _≥30 ). Results: Overall, 2591 patients with a clinical diagnosis of insomnia were included. Diagnosis of OSA _≥5 , OSA _≥15 , and OSA _≥30 was of 76.3%, 53.1%, and 32.6%, respectively. At all levels of OSA severity, No-Apnea had sensitivity ranging from 84.5 to 94.1% and specificity ranging from 58.2 to 35.1%. For screening of OSA _≥5 , OSA _≥15 , and OSA _≥30 , discriminatory ability (AUC) of No-Apnea was: 0.790 [95% confidence interval (CI) 0.770–0.810], 0.758 (95% CI 0.740–0.777), and 0.753 (95% CI 0.734–0.772), respectively. Based on AUCs, No-Apnea, STOP-Bang, and NoSAS performed similar at all levels of OSA severity. The ESS did not present satisfactory discrimination as OSA screening model. Conclusions: In a large sample of patients with insomnia, No-Apnea, STOP-Bang, and NoSAS, but not ESS, enable satisfactory and similar discrimination at all levels of OSA severity.