Association between nocturnal and morning blood pressure in patients with obstructive sleep apnea analysis: according to sex.

Background: Previous study focused on the relationship between morning blood pressure (BP) and OSA severity, and the effect of sex on hypertension in OSA. This study was undertaken to investigate the potential effect of evening systolic BP (SBP) and diastolic BP (DBP) on morning SBP and DBP for different genders in OSA patients. Methods: We conducted a retrospective study of 911 patients diagnosed with OSA via polysomnography (PSG). The association between evening and morning blood pressure was evaluated using multivariable-adjusted logistic regression models and restricted cubic splines (RCS) to assess linearity and dose-response relationships. All analyses were stratified by sex. Results: Of the 911 participants, 766 (84.08%) were male and 145 (15.92%) were female. Multivariable-adjusted analyses revealed a consistent positive association between evening and morning BP in both sexes. However, subgroup analyses identified distinct effect modifiers: in males, the association was intensified by diabetes mellitus, whereas in females, it was most evident among those with non-severe OSA. Furthermore, severe OSA significantly exacerbated morning BP surges in males with high evening BP, a synergistic effect notably absent in females. Conclusion: Evening SBP and DBP exhibited a linear association with morning BP across both sexes. However, this relationship was subject to significant effect modification: in males, diabetes mellitus intensified the association, whereas in females, it was most evident among those with non-severe OSA. Consequently, elevated evening BP precipitated marked morning BP surges in males, a phenomenon notably absent in females.