Fig. 1. Receiver-operator characteristic (ROC) curves for the SA-SDQ for an AHI cutoff of ≥5/hour and ≥15/hour. The ROC curve is a graphical plot displaying the ability to distinguish between subjects with and without a disease. Overall accuracy of the ROC curve is expressed as the area under the ROC curve (AUC), which ranges between 0 and 1. The closer AUC to 1, the better the overall diagnostic accuracy of the test. The AUC is given in the legend of each graph. SA-SDQ, Sleep Apnea of Sleep Disorder Questionnaire; AHI, apnea-hypopnea index.