Keywords
SASREM phenotype - ESS - polysomnography
Introduction: Sleep is a physiological stage divided into REM (rapid eye movement) and non-REM
(non-rapid eye movement) sleep, each of them with different characteristics and functions.
Sleep apnea syndrome (SAS) is one of the most common sleep disorders and is characterised
by successive airflow interruptions during sleep associated with oxygen desaturation,
with direct consequences on sleep quality, daytime sleepiness, cognitive, cardiovascular
and metabolic effects, among others. Obstructive respiratory events predominate during
REM sleep, when muscle relaxation is most pronounced. The clinical manifestations
and consequences of SAS are not the same in all individuals, and it is currently believed
that there is an SAS phenotype in which respiratory events predominate in REM sleep
(SAS/REM).
Objective: Our aims are to identify, in relation to the SAS/REM phenotype, the existence (or
not) of a pattern in monitoring parameters and their relationship with excessive daytime
sleepiness.
Methods: A retrospective observational study was performed, including 155 level I and II polysomnographies
(PSG) performed between January and July 2024. All PSG parameters were analysed, as
well as the Epworth Sleepiness Scale (ESS) score, the Stop-Bang (SB) score, and cervical
(CP) and abdominal perimeter (AP) measurements. The polysomnograms were analysed according
to the American Academy of Sleep Medicine v3.0 guidelines. A non-parametric statistical
approach was used; non-parametric tests were chi-squared, an extension of Fisher's
exact test, and polychoric correlation using the R language. The alpha error was set
at 5%.
Results: The majority of the sample (53.6%) was female, with a median age of 52 years (±13.5)
and a median body mass index (BMI) of 27.4 kg/m2 (±3.7). The sample means ESS score
was 7.16; SB score was 3.29; CP and AP were 37.2 cm and 95.7 cm respectively. Only
31 individuals had the SAS/REM phenotype (64.5% ♀ vs 35.5% ♂), of which only 12.9%
had an ESS score greater than 11. Chi-squared test showed no association between ESS
score and SAS/REM phenotype (p-value=0.3094). Individuals with the SAS/REM phenotype
showed strong positive correlations between age, weight, BMI, AP and SB score and
strong negative correlations between ESS score, REM sleep time and mean SpO2.
Conclusion: The sample's prevalence of SAS/REM was 20%, very similar to that found in the literature.
It is more frequent in women and although the ESS score is lower in SASREM, it is
not statistically significant.
