OBJECTIVES : Obstructive sleep apnea (OSA) is caused by complete or partial obstruction of the upper airway and has been demonstrated to be a risk factor for several diseases and to be correlated with other non-medical consequences that increase OSA’s clinical and economic burden. This study aims at systematically identifying all the conditions associated to OSA, with the ultimate objective of estimating OSA’s prevalence and economic burden in Italy.

METHODS : A systematic literature review was performed, limited to systematic reviews and meta-analyses. We excluded studies that did not provide quantitative data on the direct association of OSA with other conditions and that met predefined exclusion criteria (e.g., condition only a risk factors for OSA, pediatric population, etc). A research board with clinicians from different disciplines was performed to validate and integrate the list of associated conditions and the results from the literature for forthcoming cost-of-illness study.

RESULTS : 92 articles were included. Results show that OSA significantly increases all-cause mortality and is a risk factor for more than 50 clinical conditions in adults. These conditions are extremely heterogeneous and, inter alia, include diseases of the circulatory system (e.g., hypertension), endocrine/metabolic diseases (e.g., diabetes) and mental/behavioral disorders (e.g., depression). Among non-clinical conditions, road accidents, work-related consequences and decreased quality of life have been demonstrated to be significantly influenced by OSA. Among clinicians, there was high consensus on most of the identified conditions. For some conditions, clinicians reported heterogeneous opinions, reflecting the uncertainty found in the literature around the boundaries of OSA.

CONCLUSIONS : The clinical and economic impact of OSA is often underestimated. This study aims at providing reliable estimates of the extent of OSA consequences. This will allow to assess the total economic burden of OSA for a society and inform evidence-based policies, fundamental to ensure appropriate and sustainable therapeutic pathways for patients.