RESUMEN
Objective To investigate the prevalence of hypertension in patients with obstructive sleep apnea hypopnea syndrome (OSA) and the relationship between blood pressure (BP) with respiratory ventilation function. Methods Patients with OSA (n=3 607) were included in this study and divided into 4 groups based on their apnea-hypopnea index (AHI) scores:control group (control, n=354) with AHI<5;mild OSAHS (mild, n=658) with 5≤AHI<15;moderate OSAHS (moder?ate, n=753) with 15≤AHI<30;and severe OSA (severe, n=1 842) with AHI≥30. BP were measured at 4 time points (daytime, evening, midnight, and morning). The midnight/ daytime average BP (RN/D) and morning/evening average BP (RM/E) ratios were calculated. Finally, the general profiles, prevalence of hypertension and average BP of 4 time points were compared among 4 groups. The correlations of MBP with AHI and LSaO2 were also analyzed. Results The prevalence of hypertension as well as MBP at daytime and in the morning in the mild group (34.65%), moderate group (39.04%) and severe group (55.37%) were all higher than that in control group (22.32%)(all P<0.05). The prevalence of hypertension as well as MBP at daytime and in the morning were both higher in severe group than those in mild and moderate groups. MPB in the evening and at midnight was higher in severe group than that in moderate group than that in mild group than in control group (P<0.05). Average MBP of all four time points rise with increasing AHI (all P<0.05). The ratios of nighttime to daytime MBP (RN/D) and of morning to evening MBP (RM/E) increased with the severity of the illness (F=9.821, 18.957;P<0.001). The day? time BP correlated well with AHI and lowest oxygen saturation (LSaO2;systolic BP, r=0.195,-0.206;diastolic BP, r=0.248,-0.251, P<0.01). Daytime MBP increased gradually with increasing AHI until MPB reached 61-65, at which point it either plateaued or dropped slightly. Conclusion OSA patients have a significant increase in midnight and morning BP and lose normal BP nycterohemeral rhythm. OSA is an independent risk factor for hypertension.