HYPERTENSION AND OBSTRUCTIVE SLEEP APNEA: INSTRUMENTAL-CLINICAL CORRELATION IN A GROUP OF PATIENTS FROM SOUTHERN ITALY

Background. Sleep disordered breathing has been associated with hypertension. Obstructive sleep apnea (OSAS) is considered one of hypertension secondary causes. The OSAS-related intermittent hypoxia is associated with an increased sympathetic tone leading to hypertension. Aims. Aim of this study was to evaluate the clinical features of a cohort of patients presenting with OSAS and their eventual correlation with the degree of associated hypertension. Materials and methods. We have retrospectively studied 521patients referred to our Sleep Medicine Center in Messina (Italy) because of snoring and poor sleep quality. Each patient was clinically evaluated to detect antropometric parameters (BMI, neck and waist circumference). Blood pressure (BP) was detected at baseline in all patietns. Three hundred twenty-nine of 521 were suspected for OSAS and underwent Holter-PSG to detect the Apnea/Hypopnea index (AHI). They were then subdivided into 4 groups according to the AHI: C (healthy patients), L (mild OSAS), M (moderate OSAS), S (severe OSAS). Statistical analysis was performed by means of a specialized software (SPSS) with parametric and non-parametric tests; statistical significance was set at p<0.05. Results. The clinical features of each groups were statistically different. Patients in Group S were older and had the highest BMI, neck and waist circumference. A prevalence of male (69.5%) was present in all groups, with an M/F ratio around 2:1 in group M and S. In group S both systolic and diastolic BP values had a trend toward an increase. Moreover we found a trend to a positive correlation between AHI and BP values, more for systolic (Spearman’s R = 0.16) than for diastolic values (Sparman’s R = 0.14). Higher BP values prevailed in males (81,6%) over females (18.4%). However, no correlation between AHI, mean nocturnal SaO2, BMI and age was statistically associated with an increased risk for hypertension. Discussion Our results confirm a higher prevalence of hypertension in elderly obese patients with the highest AHI, especially in male subjects. This male preponderance might be related to the overall higher prevalence of male patients in our population, rather than to a real statistical difference related to AHI. We were able to detect hypertension in patients with higher AHI despite no clear association of BP values to the OSAS severity degree. Conclusions Hypertension and OSAS are two important clinically associated conditions. Their specific correlation needs to be further investigated considering their important cerebrovascular and cardiovascular consequences.