Obstructive sleep apnea syndrome: The relationship between some cardiovascular disease and different apnea-hypopne index definition

OSAS is characterized by repetitive apnea and hypopneas during sleep and closely associated with cardiovascular diseases, hypertension and excessive daytime sleepiness. In this study, we investigated whether there is an association between newly defined apnea-hypopnea index (AHI) criteria and cardiovascular diseases, hypertension and excessive daytime sleepiness.We evaluated all patients who referred from the Departments of Chest Diseases and Ear-Nose and Throat to Sleep Center in Karadeniz Technical University, School of Medicine between Sep 2008 and Sep 2009. Of them, 120 patients who diagnosed as OSAS were included in the study. 28 patients were included as control who have AHI<5. Currently, for the definition of apnea or hypopnea, the duration of respiratory event are considered to be at least 10 sec. In this study, in addition to the currently used AHI criteria, we also investigated new AHI indexes using different durations (lasting at least 15, 20 and 25 sec) and analyzed their association with OSAS complications using Chi-square, Student-t, Mann-Whitney U tests and one-way-ANOVA test. Factors that might predict OSAS complications (hypertension, cardiovascular events and excessive daytime sleepiness) were analyzed using univariate and multivariate logistic regression analyses.The frequency of hypertension and excessive daytime sleepiness in OSAS patients was significantly higher than control group. Contrary to hypertension, the frequency of other cardiovascular complications was not different than the control. However, we found no correlation between the severity of OSAS and the frequency of hypertension, other cardiovascular complications and excessive daytime sleepiness. Similarly, there were no correlation between newly defined AHI criteria and the OSAS complications.In conclusion, our study showed that frequency of hypertension and the excessive daytime sleepiness in OSAS patients were significantly higher, but other cardiovascular complications were not different than the control. Again, there were no relationship between the newly defined AHI indexes and the given OSAS complications.Key words: OSAS, cardiovascular diseases, hypertension