[Relationship between obstructive sleep apnea-hypopnea syndrome and hypertension]

To explore the relationship between obstructive sleep apnea-hypopnea syndrome (OSAHS) and hypertension.

There were 1149 middle aged patients who were suspected to have OSAHS underwent polysomnography (PSG) from Jan, 1999 to June, 2011. The age of the patients ranged from 45 to 65 years. The patients were divided into 10 groups according to sleep apnea hypopnea index (AHI), group 1: AHI < 5; group 2: 5 ≤ AHI < 15; group 3: 15 ≤ AHI < 30; group 4: 30 ≤ AHI < 40; group 5: 40 ≤ AHI < 50; group 6: 50 ≤ AHI < 60; group 7: 60 ≤ AHI < 70; group 8: 70 ≤ AHI < 80; group 9: 80 ≤ AHI < 90; group 10: AHI ≥ 90. The incidence of hypertension in each group was tested using crosstabs method. The correlation between AHI, lowest oxygen saturation (LSaO2), age, body mass index (BMI) and hypertension were analyzed.

Among 1149 suspected OSAHS patients, 1004 were diagnosed as OSAHS by PSG. There were positive correlation between AHI and diastolic, systolic blood pressure (r were 0.239 and 0.305, respectively, P < 0.01). AHI was independent risk factor of hypertension (P < 0.001). No statistically significant difference in the incidence of hypertension was found among group 1 and group 2, 3, group 4 and group 5, group 6 to group 10 (χ(2) were 3.821, 0.005 and 1.325, P > 0.05, respectively). There was significant difference in the incidence of hypertension among group 4 and group 1, 2, 3, group 5 and group 6 (χ(2) were 2.615 and 4.300, P < 0.05, respectively). There were two cutoff points at the AHI of 30 and 50.

With OSAHS exacerbations, the incidence of hypertension was significantly increased.