Measurement of dyspnea in patients with obstructive sleep apnea

Purpose

Patients with obstructive sleep apnea (OSA) frequently complain of exertional dyspnea. We aimed to assess its related factors and the significance of its measurement in OSA.

Methods

We evaluated 301 subjects with suspected OSA for dyspnea during activities of daily living using the Medical Research Council (MRC) scale. We analyzed the relationships between MRC grades and various subjective and objective indices. Further, the relationship of disease severity based on the apnea/hypopnea index (AHI) with these indices was examined. Results were compared between those obtained using MRC grades and the AHI.

Results

Of 301 subjects, 265 were diagnosed with OSA. Their MRC scores were worse than in non-OSA patients. Among OSA patients, 125 had MRC grade 1 (mild), 121 had MRC grade 2 (moderate), and 19 had MRC grade 3 or more (severe) dyspnea. Various measurements differed significantly between groups categorized according to the MRC scale although determinants between mild and moderate groups and between moderate and severe groups differed. AHI categorizations were not significantly related to patient-reported measurements such as the Medical Outcomes Study 36-item short form, Pittsburgh Sleep Quality Index, and Hospital Anxiety and Depression Scale scores, unlike categorization based on the MRC scale.

Conclusions

Dyspnea is an important outcome in OSA although dyspnea in OSA patients is unrelated to the sleep disorder per se. Measurement of dyspnea in patients with OSA might provide further insights into the health of these patients and clinical manifestations of this disease.     

Comparison of upper airway collapse patterns and its clinical significance: drug-induced sleep endoscopy in patients without obstructive sleep apnea,positional and non-positional obstructive sleep apnea

Purpose

To compare patient characteristics, upper airway (UA) collapse patterns and treatment outcome in obstructive sleep apnea (OSA) patients, including non-positional OSA patients (NPP) and positional OSA patients (PP), and non-OSA.

Methods

Cohort study of patients screened for OSA in 2012. Polysomnography was performed and UA was evaluated using the VOTE classification during drug-induced sleep endoscopy (DISE). Treatment outcome of MAD and UA surgery was evaluated.

Results

Eight hundred sixty patients were included. Higher BMI, larger neck circumference, and greater age were independent significant predictors for OSA. DISE was performed in 543 patients: 119 non-OSA and 424 OSA patients of whom 257 PP and 167 NPP patients. PP were younger, had smaller neck circumference, lower BMI and apnea-hypopnea index (AHI) than NPP. Collapse at velum (p?<?0.001) and oropharynx (p?<?0.001) significantly increased the odds for having OSA. Tongue base and epiglottis collapse were, on group level, not determinative for OSA or non-OSA. Complete concentric collapse (CCC) was observed less frequently in PP (31.5%) as compared to NPP (46.1%). After UA surgery, OSA often was cured or improved to less severe positional OSA. Lower efficacy of UA surgery was observed in PP as compared to NPP. No differences were observed in MAD treatment outcome.

Conclusions

Current study provides insight in patients screened for OSA: collapse at velum and oropharynx significantly determined presence of OSA and CCC occurred less frequently in PP compared to NPP. In addition, residual positional dependency is common after UA surgery. More trials are needed to gain insight in pathophysiology and treatment outcome.

     

High Prevalence of Obstructive Sleep Apnea and Its Association with Renal Function among Nondialysis Chronic Kidney Disease Patients in Japan: A Cross-Sectional Study

Summary

Background and objectives

Obstructive sleep apnea (OSA) affects one of five adults in the general population. Although a high prevalence of OSA has been reported among dialysis patients, the association between nondialysis chronic kidney disease (CKD) and OSA has not been fully investigated. This cross-sectional study aimed to investigate the prevalence of OSA among nondialysis CKD patients in Japan and the association between renal function and OSA.

Design, setting, participants, & measurements

Consecutive nondialysis CKD patients hospitalized mainly for CKD educational program, regardless of their sleep complaints, were enrolled. The diagnosis of OSA and its severity were measured using a type 3 portable monitor.

Results

Overall (n = 100, 68.0% male, median age 66.5 years, body mass index [BMI] 23.1 kg/m², estimated GFR [eGFR] 28.5 ml/min per 1.73 m²), 65% were diagnosed as OSA: mild OSA (apnea-hypopnea index [AHI] 5.0 to 14.9) in 32%, moderate OSA (AHI 15.0 to 29.9) in 25%, and severe OSA (AHI ≥ 30.0) in 8%. Multivariate logistic regression analysis revealed that a 10-ml/min per 1.73 m² decrease in eGFR was associated with a 42% increased odds of OSA after adjustment for age, BMI, and diabetes mellitus. Moreover, in a generalized linear model, eGFR was inversely correlated with AHI after adjustment for covariates.

Conclusions

This study demonstrated a high prevalence of OSA among nondialysis CKD patients in Japan and that the increased risk of OSA was significantly associated with decreased GFR among these patients. Further investigations are warranted to determine OSA''s direct influence on cardiovascular disease.     

Tissue Doppler atrial conduction times and electrocardiogram interlead P-wave durations with varying severity of obstructive sleep apnea

Objectives

Obstructive sleep apnea (OSA) has been reported to be associated with an increased risk of atrial fibrillation. The aim of this study was to investigate atrial electromechanical couplings in patients with OSA and the relationship between these parameters and P-wave dispersion (Pd).

Methods

One hundred twenty-six patients were enrolled in this study. All patients underwent polysomnographic examination. The apnea-hypopnea index (AHI) was defined as the number of apneas and hypopneas per hour of sleep. An AHI score of 5 or more was diagnosed as OSA, and an AHI score of less than 5 was diagnosed as OSA (−). Thirty-nine of the patients had an AHI score of less than 5 (group 1), 42 of the patients had AHI score between 5 and 30 (mild and moderate, group 2), 45 of the patients had an AHI score more than 30 (severe, group 3). Atrial electromechanical coupling (PA), intra-atrial, and interatrial electromechanical delay were measured with tissue Doppler imaging. P-wave dispersion was calculated from 12-lead electrocardiogram.

Results

Maximum P-wave duration was higher in group 3 compared with groups 2 and 1 (126.0 ± 16.7 vs 111.0 ± 12.5 [P < .001] and 126.0 ± 16.7 vs 99.9 ± 10.0 [P < .001], respectively). Maximum P-wave duration was higher in group 2 than in group 1 (111.0 ± 12.5 vs 99.9 ± 10.0, P < .001). P-wave dispersion was higher in group 3 compared with groups 2 and 1 (50.9 ± 11.5 vs 37.0 ± 8.6 [P < .001] and 50.9 ± 11.5 vs 27.9 ± 6.8 [P < .001], respectively). P-wave dispersion was higher in group 2 than in group 1 (37.0 ± 8.6 vs 27.9 ± 6.8, P < .001). Minimum P-wave duration did not differ between the groups. Atrial PA at the left lateral mitral annulus (lateral PA), septal mitral annulus (septal PA), and right ventricular tricuspid annulus (RV PA) were significantly higher in group 3 than in group 2 (P < .001, P = .001, and P = .009, respectively). Lateral PA, septal PA, and RV PA were higher in group 2 compared with group 1 (P < .001, P = .003, and P = .009, respectively). Interatrial electromechanical delay (lateral PA − RV PA) was significantly longer in group 3 compared with groups 2 and 1 (33.6 ± 12.1 vs 22.4 ± 9.4 [P < .001] and 33.6 ± 12.1 vs 14.9 ± 9.2 [P < .001], respectively). Interatrial electromechanical delay was longer in group 2 than in group 1 (22.4 ± 9.4 vs 14.9 ± 9.2, P = .001). There was a positive correlation between AHI and Pd, lateral PA, septal PA, RV PA, interatrial electromechanical delay, and left-sided intra-atrial electromechanical delay.

Conclusion

Prolongation of electromechanical delay and increased Pd are associated with apnea-hypopnea index (AHI) and hence the severity of disease.     

Independent association between obstructive sleep apnea and subclinical coronary artery disease

BACKGROUND: Obstructive sleep apnea (OSA) is associated with coronary risk factors, but it is unknown if OSA is associated with development of coronary disease. We evaluated the association between OSA and the presence of subclinical coronary disease assessed by coronary artery calcification (CAC). METHODS: Consecutive patients with no history of coronary disease who underwent electron-beam CT within 3 years of polysomnography between March 1991 and December 2003 were included. OSA was defined by an apnea-hypopnea index (AHI) > or = 5 events per hour, and patients were grouped by quartiles of AHI severity. Logistic regression modeled the association between OSA severity and presence of CAC. RESULTS: There were 202 patients (70% male; median age, 50 years; mean body mass index, 32 kg/m(2); 8% diabetic; 9% current smokers; 60% hypercholesterolemic; and 47% hypertensive). OSA was present in 76%. CAC was present in 67% of OSA patients and 31% of non-OSA patients (p < 0.001). Median CAC scores (Agatston units) were 9 in OSA patients and 0 in non-OSA patients (p < 0.001). Median CAC score was higher as OSA severity increased (p for trend by AHI quartile < 0.001). With multivariate adjustment, the odds ratio for CAC increased with OSA severity. Using the first AHI quartile as reference, the adjusted odds ratios for the second, third, and fourth quartiles were 2.1 (p = 0.12), 2.4 (p = 0.06), and 3.3 (p = 0.03), respectively. CONCLUSIONS: In patients without clinical coronary disease, the presence and severity of OSA is independently associated with the presence and extent of CAC. OSA identifies patients at risk for coronary disease and may represent a highly prevalent modifiable risk factor.     

Screening for hypothyroidism in sleep apnea.

Primary sleep apnea-hypopnea syndrome (obstructive sleep apnea [OSA]) and hypothyroidism have many signs and symptoms in common. The overlap in clinical presentation, and the sleep-disordered breathing that can accompany hypothyroidism, create a significant risk of misdiagnosis of sleep apnea among patients referred to sleep clinic who have undiagnosed hypothyroidism. We determined the point prevalence of hypothyroidism in our sleep clinic patients with newly diagnosed sleep-disordered breathing. Of 290 sequential patients referred to sleep clinic, 200 (69%) patients judged at high risk for OSA underwent polysomnography (PSG) and biochemical screening for hypothyroidism. Of these, 124 (62%) were judged to have sleep apnea. This included three patients (1.5% of patients undergoing PSG or 2. 4% of those judged to have OSA) who were also discovered to have previously undiagnosed hypothyroidism. These three patients with "secondary" sleep apnea were treated with thyroxine therapy alone, and followed with sequential sleep studies and serum thyroid hormone assays; symptoms, sleep-disordered breathing, nocturnal hypoxia, and thyroid deficiency resolved simultaneously. We conclude that biochemical screening for hypothyroidism is required to prevent inadvertent misdiagnosis of hypothyroid sleep-disordered breathing as primary sleep apnea, and that it is a cost-effective component of the investigation of sleep apnea.     

Influence of subclinical hypothyroidism and T4 treatment on the prevalence and severity of obstructive sleep apnoea syndrome (OSAS)

BACKGROUND: Obstructive sleep apnoea (OSA) and subclinical hypothyroidism are relatively frequent disorders that may be causally linked. However, discordant results exist on the prevalence and severity of OSA in subclinical hypothyroidism. The aim of this study was to compare the prevalence and severity of sleep-disordered breathing in individuals with or without subclinical hypothyroidism, and to investigate the possible effect of levothyroxine treatment on these patients. PATIENTS AND METHODS: One hundred and eight subjects were consecutively enrolled and divided in 3 groups, according to the TSH levels and levothyroxine therapy. The first group (Group A) was represented by 63 subjects with normal TSH and thyroid function. The other two groups included patients affected by subclinical hypothyroidism; one group (Group B) treated with levothyroxine, while the other group (Group C) was never treated with levothyroxine. Anthropometric, respiratory and polysomnographic data were evaluated in all individuals. RESULTS: The percentage of OSA, neck circumference, and body mass index (BMI) were not statistically different among the 3 groups. Respiratory disturbance index (RDI) as well as the percentage of the total number of events (apnoea-hypopnoea) by total sleep time (TST) with <90% oxyhemoglobin saturation (TSTSaO2 <90%) were not different among the groups. When we observed OSA patients, the only significant difference between groups B and C was represented by the Epworth Sleepiness Scale (ESS) (p=0.005). CONCLUSION: This study shows that subclinical hypothyroidism and treatment with levothyroxine do not influence the prevalence and severity of OSA, while sleep propensity is increased by untreated subclinical hypothyroidism.     

Predicting uptake of continuous positive airway pressure (CPAP) therapy in obstructive sleep apnoea (OSA): a belief-based theoretical approach

Purpose

Obstructive sleep apnoea (OSA) is a common disorder, for which continuous positive airway pressure (CPAP) therapy is a standard treatment. Despite its well-established efficacy, many patients choose not to initiate CPAP treatment. The present study investigated the degree to which biological measures (e.g. Apnoea–Hypopnoea Index [AHI]), symptom experiences (e.g. fatigue) and illness representations (e.g. perceived consequences) predict the decision of individuals newly diagnosed with OSA to undergo a trial of CPAP therapy.

Methods

Four hundred forty-nine individuals (316 males) newly diagnosed with OSA. Epworth sleepiness scale (ESS), Fatigue Severity Scale, Depression Anxiety Stress Scale and Illness Perception Questionnaire-Revised (IPQ-R) were administered at time of sleep study. These, patient demographics and sleep study variables were used to determine factors predicting patient decision to proceed with a trial of CPAP.

Results

The participants were most likely to attribute their OSA to unchangeable and psychological factors. For those with moderate OSA (AHI, 15 to 30) IPQ-R illness consequence was predictive of decision to initiate CPAP (p = 0.002). For severe OSA (AHI >30) age, ESS and IPQ illness causal beliefs were predictive of decision to initiate CPAP (p < 0.001).

Conclusions

Illness beliefs are important determinants of the choice of recently diagnosed OSA patients whether or not to undertake a trial of CPAP therapy. Concerns about illness consequences were important in those with moderate OSA. In severe OSA, sleepiness symptoms are more prominent and a more significant determinant of CPAP uptake along with age and causal beliefs.     

NREM-AHI greater than REM-AHI versus REM-AHI greater than NREM-AHI in patients with obstructive sleep apnea: clinical and polysomnographic features

Purpose  

Previous studies show a high prevalence of obstructive sleep apnea (OSA) patients with a higher non-rapid eye movement (NREM) apnea–hypopnea index (AHI) (NREM-AHI) than rapid eye movement (REM) AHI (REM-AHI). However, the clinical significance of this phenomenon in patients with OSA is unknown. This study aimed to investigate whether there were significant differences in clinical and polysomnographic features between the NREM-AHI > REM-AHI group and the REM-AHI > NREM-AHI group and to determine whether NREM-AHI > REM-AHI or REM-AHI > NREM-AHI is a specific clinical entity.     

Accuracy of positive airway pressure titration through telemonitoring of auto-adjusting positive airway pressure device connected to a pulse oximetry in patients with obstructive sleep apnea

Purpose

In COVID-19 era, all forms of access of patients to the sleep units should be reduced as much as possible when implementing telemedicine. In the field of obstructive sleep apnea (OSA) therapy with positive airway pressure (PAP) devices, telemedicine includes the use of built-in software (BIS) and storage of PAPs and remote-controlled data (BISrc data) that are processed and transmitted daily to sleep units. We compared two methods of evaluating the final residual severity of OSA patients in home PAP titration: BISrc data versus nocturnal portable multichannel monitoring (PM) data in PAP (reference method) and to verify whether the efficacy PAP therapy guided by BISrc data was clinically adequate.

Methods

We conducted a real-life prospective study in newly diagnosed patients with OSA. Patients used an auto-adjusting positive airway pressure (AirSense 10 ResMed) with a pulse oximeter that allows daily transfer of BISrc data (apnea hypopnea index [AHI] and SaO₂) and remote changes in ventilator setting. Once the PAP titration was completed, the pressure value or ranges were kept constant for 3 days and home PM was repeated.

Results

There were 41 patients with moderate to severe OSA who completed the study. When considering AHI only, the diagnostic accuracy of BISrc on the third day was equal to 97.5%; when considering AHI > 10/h, ODI > 10/h, and SaO₂ < 90%, the diagnostic accuracy slightly decreased to 90.2%.

Conclusion

In clinical practice, the two measurement methods are equivalent. The use of BISrc data for home titration would reduce the access to sleep units. We urge that widespread use of BISrc be promoted in the current practice of management of OSA.     

Soft palate length and upper airway relationship in OSA and non-OSA subjects

Background  

The narrowest area of the airway between the posterior nasal opening and the epiglottis is usually located in the retro palatal area. Many consider this the most likely site of airway obstruction during an obstructive sleep apnea (OSA) event. The aim of this study was to investigate the differences in soft palate and airway length between OSA and non-OSA patients.     

Severity of obstructive sleep apnea is associated with elevated plasma fibrinogen in otherwise healthy patients

Purpose

Obstructive sleep apnea (OSA) has been implicated in both cardiovascular and cerebrovascular diseases. Systemic inflammation and coagulation may be related to cardiovascular pathophysiology in patients with OSA. Fibrinogen is a major coagulation protein associated with inflammation, and long-term elevated plasma fibrinogen is associated with an increased risk of major cardiovascular diseases. We assessed whether severity of OSA is associated with levels of fibrinogen in newly diagnosed, untreated, and otherwise healthy OSA patients.

Methods

We studied 36 men with OSA and 18 male control subjects (apnea–hypopnea index [AHI] <5 events/h). OSA patients were divided into mild (AHI ≥5?Results Fibrinogen levels were significantly elevated in patients with severe OSA compared to both control (P?=?0.003) and mild OSA (P?=?0.02) subjects after adjustment for covariates. However, there were no significant differences in fibrinogen levels between mild OSA and control subjects. Fibrinogen levels were directly related to AHI and arousal index and inversely related to mean and lowest oxygen saturation during sleep.

Conclusions

Severity of OSA was associated with increased fibrinogen level independent of other factors, suggesting that apneic events and oxygen desaturation during sleep are mechanisms for increased fibrinogen levels in patients with OSA.     

Elevated Posture for the Management of Obstructive Sleep Apnea

This study aimed to evaluate the effectiveness of elevated posture in the management of obstructive sleep apnea (OSA). Fourteen subjects presenting with mild-moderate OSA, (apnea-hypopnea index [AHI] 10 to 60/h), were included in a randomized crossover investigation. A shoulder-head elevation pillow (SHEP) was compared with nasal continuous positive airway pressure (nCPAP) therapy. Treatment success was defined as AHI 10/h and partial success as AHI > 10 < 16/h. Four subjects achieved treatment success with the SHEP and three achieved partial success. The remaining seven subjects were treatment failures. In contrast, success was achieved with nCPAP in 12 subjects. One subject achieved partial success and one was a treatment failure. With the SHEP, the mean AHI decreased from 27 ± 12/h to 21 ± 17/h. With nCPAP, the mean AHI was 5 ± 3/h; (p= 0.008 for the difference between treatments). Although somewhat variable, these data provide evidence that elevated posture during sleep is helpful in the management of OSA in some individuals. Results support the use of elevated posture as second-line therapy in the management of OSA. However, no relationships could be identified between baseline data, including the identification of positional OSA, and objective outcomes that might predict patients who are likely to benefit from treatment in an elevated position.     

Nocturnal hypoxemia biomarker predicts sleepiness in patients with severe obstructive sleep apnea

Purpose

This study aims to assess the association between excessive daytime sleepiness (EDS) and variables extracted from the pulse-oximetry signal obtained during overnight polysomnography.

Methods

A cross-sectional design was used to study the relation between four hypoxemia variables and EDS as determined by Epworth Sleepiness Scale scores (ESSS) in 200 consecutive patients, newly diagnosed with obstructive sleep apnea (OSA), as defined by an apnea–hypopnea index (AHI)?≥?15. Hypoxemia measurements were compared between sleepy (ESSS?≥?10) and nonsleepy (ESSS?<?10) patients before and after dichotomizing the cohort for each hypoxemia variable (and for AHI) such that there were 35 (165) patients in each of the corresponding higher (lower) subcohorts. The hypoxemia variables were combined into a biomarker, and its accuracy for predicting sleepiness in individual patients was evaluated. We planned to interpret prediction accuracy above 80 % as evidence that hypoxemia predicted EDS.

Results

Hypoxemia was unassociated with sleepiness in OSA patients with AHI in the range of 15 to 50. In patients with AHI?>?50, the hypoxemia biomarker (but not individual hypoxemia variables) predicted sleepiness with 82 % accuracy.

Conclusion

Nocturnal hypoxemia as determined by a polyvariable biomarker reliably predicted EDS in patients with severe OSA (AHI?>?50), indicating that oxygen fluctuation had a direct role in the development of EDS in patients with severe OSA.     

Overnight fluid shifts in subjects with and without obstructive sleep apnea

Objective

To investigate the characteristics of baseline body fluid content and overnight fluid shifts between non-obstructive sleep apnea (non-OSA) and obstructive sleep apnea (OSA) subjects.

Methods

A case-controlled study was performed between February 2013 and January 2014, with 36 (18 OSA and 18 non-OSA) outpatients enrolled in this study. Polysomnographic parameters and results of body fluid were compared between the two groups.

Results

There were no differences in age, weight, and body mass index (BMI) between groups. Compared with the non-OSA group, OSA group had significantly higher neck circumference (NC) and fluid volume shift in the legs. OSA patients had higher left and right leg fluid indices than non-OSA subjects. There were significant correlations between apnoea-hypopnoea index and baseline fluid indices in both legs as well as the reduction in overnight change in both legs fluid volume. The increase in NC was also significantly correlated with the reduction in overnight change in both legs fluid volume, but not with the change in head and neck fluid volume. There were significant correlations between change in NC and increased fluid shifts in head and neck volume.

Conclusions

OSA patients had a higher baseline fluid content in both legs as compared with non-OSA subjects, which may be the basic factor with regards to fluid shifts in OSA patients. The increase in head and neck fluid shift volume did not directly correlate with the severity of OSA.     

Etiologic discussion and clinical relevance of thyroid ultrasonography in subclinical hypothyroidism. A retrospective study in 1845 patients

Background

Acquired subclinical hypothyroidism in adulthood is mainly due to autoimmune thyroiditis. In the absence of a goiter or a palpable firm thyroid, measurement of thyroid antibodies can improve the diagnosis. Whether thyroid antibodies are detected or not, what might be the clinical relevance of ultrasonography in this setting?

Methods

We studied 1845 cases of subclinical hypothyroidism in adults recruited for symptoms indicative of hypothyroidism or thyroid pathology. All patients were screened for thyroid antibodies and underwent an ultrasonographic thyroid examination.

Localisation

Multicentric retrospective study.

Results

Chronic autoimmune thyroiditis was confirmed in 70% of patients. Thyroid antibodies were undetectable in 30% of patients. In all patients, thyroid ultrasound facilitated measurement of the thyroid volume and detection of non-palpable nodules and therefore allowed biopsy. In patients negative for thyroid antibodies, ultrasonography suggested autoimmune thyroiditis in 31% of cases. Ultrasonography did not contribute to diagnosis in a large number of patients without nodules and in case of normal echostructure. The strategy of thyroid hormone replacement therapy was not influenced by ultrasonographic data. Thyroid biopsies detected smears suspected to be cancerous in 10 patients (4%). Cancer was confirmed in nine patients after surgery. Ultrasonography displayed suspicious aspects in six patients.

Conclusion

In subclinical hypothyroidism, thyroid ultrasonography is not required for the diagnosis of autoimmune thyroiditis but is useful for patients with abnormal thyroid palpation and allows detection of non-palpable thyroid nodules. For patients that were negative for thyroid antibodies, thyroid ultrasonography can improve diagnosis for some patients, allowing detection of autoimmune thyroiditis.     

Serum levels of magnesium and their relationship with CRP in patients with OSA

Background

Low levels of magnesium (Mg) are associated with chronic inflammatory stress. Some animal studies have reported that a moderate deficiency of Mg, similar to that which occurs in humans, may increase inflammatory or oxidative stress stimulated by other factors, such as disrupted sleep or sleep deficiency.

Purpose

This cross-sectional study evaluated the relationship between serum levels of Mg and the inflammatory response in patients with a new diagnosis of obstructive sleep apnea (OSA).

Methods

This clinical, retrospective study registered 68 patients with newly diagnosed mild to severe OSA and 30 without OSA. The Apnea–Hypopnea Index (AHI), oxygen desaturation index (ODI), time until blood hemoglobin oxygen saturation <90 % (SpO₂ <90 %), and mean blood hemoglobin SpO₂ were measured. Serum levels of Mg, plasma C-reactive protein (CRP), and total sleep time (TST) by polysomnography were also measured.

Results

Mg levels were lower in patients with OSA than those in controls matched for age, sex, and body mass index (BMI). Patients with OSA had substantially higher plasma CRP concentrations than controls. A negative correlation was observed between the AHI and ODI and Mg levels. Significant differences in Mg and CRP levels were observed between patients with AHI scores of 5–15 and scores ≥30 based on OSA severity but independent of BMI. Furthermore, the AHI, ODI, TST <90 %, and mean SpO₂ significantly correlated with CRP. A significant negative correlation was observed between Mg and CRP levels (p < 0.0001).

Conclusion

Our results show that Mg levels changed depending on the presence and severity of OSA. Low levels were associated with a higher CRP concentration in patients with OSA.

     

Obstructive sleep apnea and the metabolic syndrome in an elderly healthy population: the SYNAPSE cohort

Background

Obstructive sleep apnea syndrome (OSA) has been recently considered as a cause and a component of the metabolic syndrome (MetS), previous studies showing the presence of OSA in about half of middle-aged patients having MetS. To date, no study has considered the association of OSA and MetS in the elderly. In this study we examine the prevalence of MetS and its strength association among healthy elderly OSA subjects.

Methods

A cohort of 806 subjects aged 68.5?years, participants of a 7-year follow-up study, was examined. All subjects underwent clinical evaluation, blood sample measurements, and an at-home polygraphy. OSA was assessed as an apnea/hypopnea index (AHI) >15, and MetS was diagnosed according to the Adult Treatment Panel III.

Results

In the total group, 9.8% of cases met criteria for MetS with a prevalence similar in men and women. Of the entire group with Mets, 51.3% were women and 48.7% men. OSA was diagnosed in 55.9% of the sample, and among the OSA group, 12.5% had MetS. Oxyhemoglobin desaturation index (ODI, p?p?=?0.003) were found significantly higher in subjects with MetS than in those without it. Most of MetS components were significantly associated with AHI and ODI, the relationship stronger with ODI. After adjustment for covariables such as obesity, gender, and presence of diabetes, ODI was independently associated with three MetS components, glycemia (p?p?=?0.002), and triglyceride levels (p?=?0.02). Sleepiness, autonomic arousal index, and sleep duration had no effect on the metabolic parameters.

Conclusions

In elderly subjects, the association between OSA and MetS was stronger for hyperglycemia and hypertension. Among factors explaining this association, hypoxemia appears to be the most important factor without any effect of indices of sleep fragmentation, sleep duration, and sleepiness.     

Clinical and cardiovascular characteristics of patients with obstructive sleep apnoeas without excessive daytime sleepiness

Objectives

To investigate whether patients with obstructive sleep apnoea (OSA) without excessive daytime sleepiness (EDS) have cardiovascular problems and different clinical characteristics from OSA with EDS.

Methods

Two groups of patients were compared retrospectively, one without EDS (Epworth <11) and another control group with EDS (Epworth>10), adjusted for sex, age, body mass index (BMI) and apnoea-hypopnoea index (AHI). The diurnal and nocturnal symptoms of OSA were analysed along with, polysomnography variables, prevalence of hypertension, diabetes mellitus, hyperlipaemia and history of previous cardiovascular events. A logistic regression was performed adjusted for multiple confounding factors to identify the variables associated with OSA without EDS.

Results

A total of 166 patients without EDS were studied (Epworth 7.2±2.4) and 295 with EDS (Epworth 14.5±2.5). In the adjusted multivariate logistic regression, OSA without EDS is independently associated with a feeling of restful sleep (95% CI: 1.70 to 3.93), less intellectual deterioration (95% CI: 0.30 to 0.95) and less effective sleep (95% CI: 0.96 to 0.99). No differences were found as regards prevalence of cardiovascular comorbidity, previous cardiovascular events, sleep structure or nocturnal clinical symptoms of OSA. When the patients who were in the extreme quartiles of the Epworth scale were analysed, the results obtained were equivalent to those of the whole series, with only intellectual deterioration disappearing from the final model.

Conclusions

After adjusting for confounding variables, OSA without EDS has a similar prevalence of cardiovascular comorbidities and less diurnal symptoms than OSA with EDS.     

The relationship between high-sensitivity C-reactive protein levels and the severity of obstructive sleep apnea

Background and objective  

There is an increased risk of cardiovascular and cerebrovascular events in patients with obstructive sleep apnea (OSA). High-sensitivity C-reactive protein (hs-CRP) is a marker that predicts atherosclerotic complications. However, there are contradictory results about the correlation between serum hs-CRP levels and OSA severity. The purpose of this work was to evaluate the relationship between hs-CRP levels and the severity of OSA in newly diagnosed OSA patients.