A new approach for the assessment of sleepiness and predictivity of obstructive sleep apnea in drivers: A pilot study

Background: Falling asleep behind the wheel is one of the most relevant consequences of obstructive sleep apnea (OSA). We created a new screening questionnaire, named the Driver Sleepiness Score (DSS), aiming to assess sleepiness in drivers with suspected OSA. The primary aim of our study was to evaluate sleepiness in drivers with a suspicion of OSA by the DSS in order to assess its correlation with the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and total sleep time with oxyhemoglobin saturation below 90% (TST90). We also aimed to assess the diagnostic accuracy of DSS for three different cutoffs of AHI (AHI = 5, AHI = 15, AHI = 30), which allow stratification of the severity of OSA.

Materials and methods: Seventy-three driving patients at risk for OSA participated in the study. DSS and the Epworth Sleepiness Scale (ESS) were both administered in operator-dependent modality and in randomized sequence.

Results: The DSS showed higher accuracy in screening patients with mild OSA [area under curve (AUC): 0.88 vs 0.74] and moderate OSA (AUC: 0.88 vs 0.79), whereas ESS showed higher accuracy in screening patients with severe OSA (AUC: 0.91 vs 0.78). A DSS score ≥ 7 is the optimal cutoff for distinguishing true positives from false positives for the presence of OSA and for its different severity levels. The administration of both questionnaires increases the accuracy for the detection of all OSA severity levels.

Conclusions: If validated, DSS may qualify as a new screening tool specifically for drivers with the suspicion of having OSA, in combination with the ESS.