Optimizing the step-by-step diagnosis in obstructive sleep apnea: Comparison of Epworth sleepiness scale, Erlangen Questionnaire and biomarker NAP-2

In case of suspected obstructive sleep apnea (OSA) a step-by-step diagnosis should be carried out. The recommended levels 1 – 3 (medical history, questionnaires, examination, polygraphy) prove to be time-consuming and costly in clinical routine. The aim of this pilot study is therefore the development of an effective screening procedure for the optimization of the diagnostic levels 1 – 3 upstream of the gold standard polysomnography. The diagnostic tools Epworth Sleepiness Scale (ESS), Erlangen Questionnaire (EQ) and the biomarker NAP-2 were compared with regard to their sensitivity and specificity.

In the period from 01/2015 to 04/2018 a total of 123 persons (n = 123) were included in the pilot study at the Department of Otorhinolaryngology of the University Hospital Erlangen. 90 patients with OSA, confirmed by polysomnography (mean AHI = 36, age = 52, BMI = 32) and 33 controls (mean age = 39, BMI = 25). The completion of the questionnaires ESS and EQ as well as the blood samples for quantifying NAP-2 serum levels by means of ELISA were carried out before the polysomnography.

The ESS and the EQ achieved a sensitivity and specificity of 48% and 82%, respectively of 81% and 54% in this study group. The biomarker NAP-2 achieved a sensitivity of 81% and a specificity of 61%, with a positive predictive value of 85% and a negative predictive value of 54%.

In the context of non-invasive diagnostics, the EQ seems to be superior to the internationally renowed ESS due to its higher sensitivity. The use of the biomarker NAP-2 achieves the highest sensitivity and specificity compared to the questionnaires (ESS, EQ). In this pilot study serum level of NAP-2 appear to be comparable to the current gold standard polygraphy.

Publication History

Publication Date:
23 April 2019 (online)