'REM-related OSA': a forgotten diagnostic? Possible path to under-diagnosing sleep apnea.

Introduction: Restrictive criteria are proposed to define the disorder 'REM-related OSA' disorder, and questions remain about its nosological transcendence and clinical management.

Aim: To evaluate the criteria proposed to define 'REM-related OSA', its relationship with cardio-metabolic comorbidity, and aspects related to it diagnostic.

Patients And Methods: Retrospective observational study of clinical and polysomnographic data from outpatients. 525 patients over 18 years old who had an Apnea Hypopnea Index (AHI) = 5 (total, or partial, in REM and/or NREM) were included.

Results: 'Phase-dependent' subgroups were formed using a criterion based on the 'ratio = 2' and another 'strict' criterion based on a partial AHI = 5 compared to another partial AHI <5 (in REM or in NREM). In the 'strict REM-related OSA' subgroup, half of the patients showed an overall AHI < 5, with less severity in the respiratory parameters, but with lower comorbidity percentages. With the current diagnostic criteria, these patients would be excluded from the sleep apnea diagnosis.

Conclusions: The application of the strict criterion to detect 'REM-related OSA' makes it possible to filter milder forms of sleep apnea associated with percentages of cardiovascular and/or metabolic comorbidity that are not significantly different from other more severe forms of sleep apnea. To avoid under-diagnosis, it would be advisable to review the sleep apnea diagnostic criteria and the indications of the reduced sleep apnea diagnostic techniques.