The role of screening questionnaires in the assessment of risk and severity of obstructive sleep apnea - polysomnography versus polygraphy.

Obstructive sleep apnea (OSA) is a disease of significant importance, which may lead to numerous severe clinical consequences. The gold standard in the diagnosis of this sleep-related breathing disorder (SRBD) is polysomnography (PSG). However, due to the need for high expertise of staff who perform this procedure, its complexity, and relatively low availability, some simpler substitutes have been developed; among them is polygraphy (PG), which is most widely used. Also, there is a variety of questionnaires suitable to assess the pre-test probability and severity of OSA. The most frequently used ones are the STOP-BANG questionnaire (SBQ), NoSAS questionnaire, and Berlin questionnaire (BQ). However, they have different sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) when being used in various populations. The aim of this study is to provide a concise and clinically-oriented review of the most frequently used questionnaires, with special attention to its strengths and limitations. Moreover, we discuss whether PSG or PG would be more preferred for confirming OSA diagnosis with the highest likelihood.