INTRODUCTION: Evidence suggests biological sex-related differences in sleeping patterns possibly due to hormonal effects in sleep.

OBJECTIVES: To assess potential sleeping pattern differences between male and female patients.

METHODS: Retrospective study including patients submitted to polysomnography between January-December 2022 without Obstructive Sleep Apnea (OSA) diagnosis.

RESULTS: 119 patients were included, 65,5% female, with a mean age of 48,5±14,1 years. The most frequent clinical suspicion was OSA (n=49), followed by hypersomnia (n=26), parasomnia (n=22) and insomnia (n=20); females were more prevalent in all clinical suspicion groups except OSA (p<0.001). Median pre-test Epworth Sleeping Scale (ESS) was 10 (0;22); reported median ESS was significantly higher for females (11 vs 7; p=0.032). Median total sleeping time was 386 minutes (min) (13,5;556), with median sleep efficiency of 83,4% (2,6;98); no statistically significant sex-related differences were found. Likewise, there were no differences in N1, N2, N3 and REM sleep proportions when adjusted to age and medication. Females showed higher median REM sleep latency (140,5 min vs 98,8 min; p=0.009) and fewer sleep cycles (3 vs 4; p=0.011). Median oxygen saturation (SpO2) was lower in males (94,9% vs 96%; p=0.003), who presented higher cumulative time with SpO2 below 90% (0,1% vs 0%; p=0.023). Most patients (n=83) were diagnosed with some form of sleep disturbance. Biological sex significantly predicted REM latency independently of age, antidepressant intake and underlying sleep disturbance (?=37.6, p=0.033).

CONCLUSION: Our sample showed significant sex-related differences in the clinical pre-test setting and sleep parameters in patients without OSA.