The Correlated Study About Serum C-reactive Protein And Interleukin-6 Levels In Obstructive Sleep Apnea Syndrome And Hypertension Patients

[Objectives]â‘ To investigate the changes of serum interleukin-6(IL-6) and c-reactive protein (CRP) levels in obstructive sleep apnea syndrome (OSAS) patients without complications and in those with obstructive sleep apnea syndrome associated hypertension(OSAS + hypertension) and explore the relation between inflammation and OSAS or OSAS + hypertension.â‘¡To examine the association between CRP, IL-6 and the elevated levels of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean artery pressure (MAP), sleep disorder, intermittent hypoxaemia.â‘¢To explore the relationship between apnea events (with the state of oxygen saturation) and the hypertension.[Methods] Sixty no other complicated inpatients were enrolled in this study. All observed subjects, according to suffer an OSAS, hypertension or not, were divided into 3 groups: a group with OSAS and normal blood pressure patients (n=18), a group with OSAS and hypertension patients (n=21), a control group with simple snoring subjects (n=21). In addition to that, according to blood pressure all observed subjects were divided into 3 groups: a group with normal blood pressure (groupâ… ,n=29); a group with grade 1 hypertension(groupâ…¡,n=11); a group with grade 2-3 hypertension (groupâ…¢,n=20). All of the cases and some of the controls performed the nocturnal polysomnography (PSG) using a computerized system and measured the blood pressure before subjects go to bed and in the next morning when he was awake. Selected Apnea hypopnea index(AHI), the percentage of time with less than 90% hemoglobin saturation level in total sleep time(%T<90%) and minimum oxygen saturation(SaO_2-min) as Sleep-breathing monitoring markers. The levels of fasting CRP and IL-6 concentrations of serum were measured in the morning after PSG and were compared among 3 groups. Sleep-breathing parameters of the 3 groups were also compared. Furthermore, we analyzed the correlations between the two factors and sleep-breathing parameters in OSAS with normal blood pressure patients and OSAS with hypertension patients respectively.[Results]â‘ AHI, %T<90% levels were significantly higher and SaO_2-min levels were significantly lower in OSAS with hypertension group than control simple snoring group as well as OSAS with normal blood pressure group (P<0.01); AHI, %T< 90% levels were significantly higher and SaO_2-min levels were significantly lower in OSAS with normal blood pressure group than control simple snoring group(P< 0.01).â‘¡When we compared the before sleep,next morning awaken blood pressure (SBP, DBP, MAP) respectively in the three groups we found that: The before sleep blood pressure of OSAS with hypertension group were significantly higher than the other two groups(P<0.05), the blood pressure levels(SBP, DBP, MAP) were no significance between OSAS with normal blood pressure group and control simple snoring group(P>0.05); The next morning after awaken blood pressure of OSAS with hypertension group were significantly higher than the other two groups(P< 0.05), the blood pressure levels were no significance between OSAS with normal blood pressure group and control simple snoring group(P>0.05). The increase value of blood pressure in OSAS with hypertension group between after awaken and before sleep was significantly higher than the other two groups(P>0.05); the increase value of blood pressure in OSAS with normal blood pressure group was no significantly higher than the control simple snoring group(P>0.05).â‘¢When compared the CRP and IL-6 levels among the three groups respectively we found that: serum CRP and IL-6 levels showed significant differences between OSAS with hypertension group and other two groups(P< 0.05). When compared between two groups by Bonferroni we found that: serum CRP levels showed significant differences between OSAS with hypertension group and control simple snoring group(P<0.05), but not between OSAS with normal blood pressure group and control simple snoring group as well as not between OSAS with hypertension group and OSAS with normal blood pressure group(P > 0.05). Serum IL-6 levels showed significant differences between OSAS with hypertension group and control simple snoring group as well as between OSAS with normal blood pressure group and control simple snoring group(P<0.05), but not between OSAS with normal blood pressure group and OSAS with hypertension group(P>0.05). Correlation analysis between OSAS severity and CRP levels was determined by Spearman's correlation. Serum CRP levels were positively correlated with AHI and %T<90% and negatively correlated with SaO_2-min. serum IL-6 levels were uncorrelated with %T<90% and SaO_2-min, but there were positive correlation was between serum IL-6 levels and AHI. Partial correlation analysis between OSAS severity and inflammatory factors were determined after controlling for age, gender, weight, hypertension and body mass index(BMI). Serum CRP levels were only positively correlated with %T<90%, and serum IL-6 levels were uncorrelated with AHI, %T<90% and SaO_2-min.â‘£When compared between the-next-morning awaken blood pressure (SBP, DBP, MAP) and inflammatory factors we found that: serum CRP and IL-6 levels, according to blood pressure dividing groups, showed skewed distribution. Through logarithmic transformation, lgCRP levels showed significant differences with SBP between normal blood pressure and grade 1 hypertension group as well as between normal blood pressure and grade 2-3 hypertension groups, but not between grade 1 hypertension and grade 2-3 hypertension groups. Serum lgCRP levels showed significant differences with DBP between normal blood pressure and grade 2-3 hypertension group, but not between normal blood pressure and grade 1 hypertension groups as well as not between grade 1 hypertension and grade 2-3 hypertension groups. Serum lgCRP levels showed significant differences with MAP between normal blood pressure and grade 1 hypertension group as well as between normal blood pressure and grade 2-3 hypertension groups, but not between grade 1 hypertension and grade 2-3 hypertension groups. Serum lgIL-6 levels showed no significant differences among the three blood pressure groups. Correlation analysis between morning hypertension severity and inflammatory factors was determined by Pearson's correlation that serum lgCRP levels were positively correlated with the-next-morning awaken blood pressure (SBP, DBP, MAP), but no correlation was seen between serum lgIL-6 levels and the-next-morning awaken blood pressure.[Conclusions]1. Measured serum CRP and IL-6 levels in OSAS and hypertension patients were useful for the study pathogenesis of OSAS complicating cardiovascular and cerebrovascular risk events.2. Patients with OSAS and hypertension missed normal nocturnal blood pressure circadian rhythm (normal dipper profile) in OSAS and hypertension patients.3. OSAS severity was no positively correlated with inflammation factors. The more intermittent hypoxemia lasting, the inflammation reaction was the more severse. The blood pressure was positively correlated with inflammation factors which indicated causality possibly existed between blood pressure and serum CRP levels in OSAS patients.4. Patients with OSAS and hypertension presented systemic inflammation which is not only essentially secondary to hypoxaemia, sleep deprivation, but also sympathetic activity, endothelial dysfunction, tissue anoxia oxidative stress and rennin-angiotensin-aldosterone system, along with elevated blood pressure and presented OSA, together playing roles.