Obstructive sleep apnea and immunity: relationship of lymphocyte count and apnea hypopnea index

Can the complete blood count be used as a reliable screening tool for obstructive sleep apnea?

PURPOSE

Since hypoxia increases erythropoietin production and inflammation, the complete blood count (CBC) has been proposed as an inexpensive alternative for obstructive sleep apnea (OSA) screening. The objective of this study was to determine whether or not intermittent hypoxia and OSA severity, as measured by the mean oxygen saturation (SpO₂) and apnea-hypopnea index (AHI), affect parameters measured by the CBC.

METHODS

This retrospective study included a total of 941 surgical patients who had a pre-operative home sleep study. The pre-operative CBC was extracted from the electronic patient records. Patients were stratified according to their AHI scores, into mild (AHI ≥ 5 - < 15), moderate (AHI ≥ 15 - < 30), and severe (AHI ≥ 30) OSA groups.

RESULTS

There were 244 patients without OSA, 294 with mild, 223 with moderate, and 180 with severe OSA. Our analysis showed that hemoglobin (P = 0.010), hematocrit (P = 0.027), and basophils (P = 0.006) showed significant changes among the different severities of OSA. For mean SpO₂, there were negative associations with body mass index (r =  - 0.287; P < 0.001), age (r =  - 0.077; P = 0.021), hemoglobin (r =  - 0.208; P < 0.001), hematocrit (r =  - 0.220; P < 0.001), red blood cells (r =  - 0.107; P = 0.001), mean corpuscular volume (MCV) (r =  - 0.159; P < 0.001), mean corpuscular hemoglobin (r =  - 0.142; P < 0.001), and basophils (r =  - 0.091; P = 0.007). All analyzed parameters remained within normal clinical range. Multivariable regression identified hemoglobin, MCV, and basophils to be independent predictors of mean SpO₂ and AHI.

CONCLUSION

Hemoglobin, MCV, and basophils were independently associated with intermittent hypoxia defined by mean SpO₂ and AHI. Adding CBC parameters to other screening tools for OSA may have additional value due to its association with changes in mean SpO_2.

Identification of Sleep Apnea Severity Based on Deep Learning from a Short-term Normal ECG

BACKGROUND

This paper proposes a novel method for automatically identifying sleep apnea (SA) severity based on deep learning from a short-term normal electrocardiography (ECG) signal.

METHODS

A convolutional neural network (CNN) was used as an identification model and implemented using a one-dimensional convolutional, pooling, and fully connected layer. An optimal architecture is incorporated into the CNN model for the precise identification of SA severity. A total of 144 subjects were studied. The nocturnal single-lead ECG signal was collected, and the short-term normal ECG was extracted from them. The short-term normal ECG was segmented for a duration of 30 seconds and divided into two datasets for training and evaluation. The training set consists of 82,952 segments (66,360 training set, 16,592 validation set) from 117 subjects, while the test set has 20,738 segments from 27 subjects.

RESULTS

F1-score of 98.0% was obtained from the test set. Mild and moderate SA can be identified with an accuracy of 99.0%.

CONCLUSION

The results showed the possibility of automatically identifying SA severity based on a short-term normal ECG signal.

Cholinergic Markers and Cytokines in OSA Patients

The role of inflammation and dysfunction of the cholinergic system in obstructive sleep apnea (OSA) has not exhaustively clarified. Thus, in this study, we explore the non-neuronal cholinergic system and the balance of T helper (Th) 17- and T regulatory (Treg)-related cytokines in OSA patients. The study includes 33 subjects with obstructive sleep apnea and 10 healthy controls (HC). The expression levels of cholinergic system component, RAR-related orphan receptor (RORc), transcription factor forkhead box protein 3 (Foxp3) and cytokines were evaluated. Th17- and Treg-related cytokines, choline levels and acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) activity were quantified in OSA and control subjects. AChE and nicotinic receptor α 7 subunit (α7nAChR) gene expression and serum levels of choline, AChE and BuChE were lower in OSA patients than in the HC group. Compared with the HC group, OSA patients exhibited an increased expression, secretion and serum levels of pro-inflammatory cytokines, a reduced expression, secretion and serum levels of transforming growth factor (TGF)β and reduced Foxp3 mRNA levels. The Th17/Treg-related cytokine ratio was higher in the OSA group. Our results confirm and reinforce the hypothesis that OSA may be considered a systemic inflammatory disease, and that an imbalance of non-neuronal cholinergic and pro/anti-inflammatory cytokines may contribute to development and progression of comorbidities in OSA subjects. The evaluation of Th17/Treg-related cytokine may provide an additional explanation for OSA pathogenesis and clinical features, opening new directions for the OSA management.

The association of hemocyte profile and obstructive sleep apnea

BACKGROUND

The hemocyte profile is one of the most frequently requested clinical laboratory tests. However, the analysis of blood cell indexes of obstructive sleep apnea (OSA) patients in previous studies was not comprehensive. And, this study aimed to fully analyze the blood routine in OSA patients.

METHODS

A retrospective study was conducted on 1087 male patients, who were admitted to the sleep center of Nanfang Hospital from May 2013 to February 2018. According to the apnea hypopnea index (AHI), patients were divided into four groups: control group (AHI < 5, n = 135), mild OSA (5 ≦ AHI < 15, n = 185), moderate OSA (15 ≦ AHI < 30, n = 171), and severe OSA (AHI ≧ 30, n = 596). Data collected included sleep parameters, complete blood routine, body mass index (BMI), age, and comorbidities.

RESULTS

In our study, leukocytes, neutrophils, lymphocytes, monocytes, eosinophils, basophils, erythrocytes, hemoglobin, hematocrit, platelets, MPV, and PDW-SD were statistically significant among the four groups based on AHI (P < 0.05), but no significant differences were found in MCV, RDW-SD, N/L, and P/L ratio (P > 0.05). Neutrophils, lymphocytes, monocytes, eosinophils, basophils, hemoglobin, hematocrit, platelets, and MPV were significantly correlated with AHI. Moreover, multiple linear regression analysis demonstrated that hematocrit (β = 73.254, P = 0.001), neutrophils (β = 1.414, P = 0.012), and lymphocytes (β = 4.228, P < 0.001) were independently associated with AHI.

CONCLUSION

Neutrophils, lymphocytes, and hematocrit were independently associated with OSA severity. And combining these three blood cell indicators could contribute to the diagnosis of OSA.

Recognition and treatment of sleep-disordered breathing: an important component of chronic disease management

Sleep-disordered breathing (SDB) is a highly prevalent condition, and is associated with many debilitating chronic diseases. The role of untreated obstructive sleep apnea (OSA) in arterial hypertension has been recognized in international guidelines. Treatment with continuous positive airway pressure (CPAP) is associated with clinically-relevant reductions in blood pressure. In heart failure (HF), SDB is associated with worse prognosis and increased mortality. Major HF guidelines recommend that patients should be treated for sleep apnea to improve their HF status. Severe OSA increases the risk of arrhythmias, including atrial fibrillation, influences risk management in stroke, and is highly prevalent in patients with type 2 diabetes. Effective treatment with CPAP improves the success of antiarrhythmic interventions, improves outcomes in stroke and reduces hyperglycemia in diabetes. Patients with coronary artery disease also have a high prevalence of SDB, which is independently associated with worse outcomes. The role of CPAP for secondary cardiovascular prevention remains to be determined. Data from large, well-conducted clinical trials have shown that noninvasive ventilation, targeted to markedly reduce hypercapnia, significantly improves survival and reduces readmission in stable hypercapnic chronic obstructive pulmonary disease. The association of SDB with chronic diseases contributes to the high healthcare costs incurred by SDB patients. SDB also has an important negative impact on quality of life, which is reversed by CPAP treatment. The high prevalence of SDB, and its association with diseases that cause significant morbidity and mortality, suggest that the diagnosis and management of SDB is an important therapeutic goal. First, adherent CPAP treatment significantly improves the quality of life of all patients with SDB; second, it eliminates the negative impact of untreated SDB on any associated chronic diseases; and third, it significantly reduces the increased costs of all hospital and medical services directly associated with untreated SDB. In short, the recognition and treatment of SDB is vital for the continued health and wellbeing of individual patients with SDB.

Assessment of the role of serum ischemia-modified albumin in obstructive sleep apnea in comparison with interleukin-6

OBJECTIVES

There is limited and contradictory information regarding the role of serum ischemia-modified albumin (IMA) in obstructive sleep apnea (OSA). In this study we examine the effects of OSA and obesity on IMA and interleukin-6 (IL-6), and detect whether IMA and IL-6 may be potential biomarkers in OSA.

METHODS

Fifty-one males who underwent all night polysomnography test were included into the study. Body-mass index (BMI) and apnea-hypopnea index (AHI) of all patients were determined. Serum IMA and IL-6 levels, erythrocyte sedimentation rate (ESR), complete blood count, routine blood biochemistry and thyroid function tests were performed.

RESULTS

Mean IMA [0.36 (± 0.04) U/ml, 0.89 (± 0.15) U/ml], mean IL-6 [1.01 (± 0.19) pg/ml, 2.02 (± 1.19) pg/ml] and mean ESR [4.14 (± 2.5) mm/h, 14.35 (± 13.7) mm/h] levels showed significant difference between non-OSA and OSA groups (P = 0.005, P < 0.001, P < 0.001, respectively). Sensitivity of IMA in distinction of non-OSA/OSA was equal to IL-6 and higher than ESR. IMA was also a stronger predictive factor than IL-6 and ESR in the evaluation of OSA groups (severe/mild/moderate OSA and non-OSA). IMA was the sole distinctive biomarker in assessment of obese and non-obese cases. IMA correlated with IL-6, AHI and ESR.

CONCLUSION

Serum IMA may be a valuable oxidative stress indicator for OSA and could act as a better biomarker than IL-6 for reflecting the presence and the severity of OSA.

The Significance of the Relative Lymphocyte Count as an Independent Predictor of Cardiovascular Disease in Patients with Obstructive Sleep Apnea Syndrome

OBJECTIVE

The aim of this study was to determine whether or not relative lymphocyte count (RLC) is associated with cardiovascular disease (CVD) in patients with obstructive sleep apnea syndrome (OSAS).

SUBJECTS AND METHODS

In this study, 141 patients diagnosed with OSAS using polysomnography were enrolled. Patients were classified according to the severity of OSAS as determined by the apnea-hypopnea index (AHI) and presence of CVD. Lymphocyte count and other hematological parameters at complete blood count were determined and compared between patients with and without CVD. Multivariate regression analysis was used to estimate the associated factors for presence of CVD.

RESULTS

Absolute and relative lymphocyte counts were lower in the OSAS patients with CVD compared to those without CVD (mean absolute lymphocyte counts: 2.0 × 103 vs. 2.5 × 103 µl, p = 0.004, and mean RLC: 28.3 vs. 33.9%, p = 0.001, respectively). OSAS patients with CVD (14.2) had higher red cell distribution width values than the patients without CVD (13.4) (p = 0.005). Multivariate analysis identified RLC as an independent predictor of CVD in patients with OSAS (odds ratio = 0.9, 95% CI: 0.85-1.0, p = 0.042).

CONCLUSION

RLC was identified as an independent predictor of CVD in patients with OSAS. Since RLC is a widely available diagnostic tool with no additional costs over the routinely performed complete blood count, it can be used for predicting CVD in patients with OSAS.

Sleep apnoea patients have higher mortality when confronting sepsis

BACKGROUND

Sleep is essential for the maintenance of an intact immune function. Patients with sleep apnoea experience frequent sleep interruption due to apnoea-related arousals, possibly adversely impacting their immunity and affecting their outcomes when confronting sepsis. This case-control study aimed to compare the outcomes of sepsis patients with and without sleep apnoea.

METHODS

From 2000 to 2009, 168 sleep apnoea patients who were first admitted for sepsis were identified from the Taiwan National Health Insurance Research Database. Also, 672 sepsis patients without sleep apnoea, who were matched by age, gender and Charlson's comorbidity index scores, served as controls. Hospital outcomes of the two groups were compared. Binary logistic regression was employed for multivariate analysis.

RESULTS

The mortality rates of sepsis patients with and without sleep apnoea were 60.1% and 47.9%, respectively (P = 0. 005). After multivariate adjustment, sleep apnoea (OR: 1.805, 95% CI: 1.227-2.656, P = 0.003), presence of shock (OR: 3.600, 95% CI: 2.144-6.046, P < 0.001) and number of organs with dysfunction (OR: 1.591, 95% CI: 1.087-2.329, P = 0.017) were found to be independently associated with mortality. Sleep apnoea patients who needed continuous positive airway pressure treatment had an even higher risk of mortality.

CONCLUSIONS

Sepsis patients with sleep apnoea may have poorer hospital outcomes than those without sleep apnoea.

The treg/th17 imbalance in patients with obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is a chronic inflammatory disease regulated by T lymphocytes. Our purpose is to assess the pattern of Th17 cells and CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells in peripheral blood of patients with OSAS. Fourty-four OSAS men and 20 healthy volunteers were enrolled. Twenty-three patients were classified into mild to moderate group and 21 cases were classified into severe group according to the severity of OSAS. We detected the frequencies of Th17 and Treg and related serum cytokines secretion and expressions of key transcription factors. OSAS patients revealed significant increase in peripheral Th17 number, Th17-related cytokines (IL-17 and IL-6), and RORγt mRNA levels. They also presented a significant decrease in Treg number, Treg-related cytokines (TGF-β₁), and Foxp3 mRNA levels as compared with normal persons. As a result, the Th17/Treg ratios were markedly more upregulated in OSAS patients than those in control group. Furthermore, the Th17/Treg ratio was positively related to the severity of OSAS and serum levels of C-reactive protein. The development of OSAS may be associated with peripheral Th17/Treg imbalance and characterized by a proinflammatory cytokine microenvironment. These results opened an alternative explanation for the substantial activation of immune cells in OSAS and the development of related complications.