Minimum Nocturnal Oxygen Saturation Research Articles

Prediabetes Is Associated with Increased Prevalence of Sleep-Disordered Breathing.

Type 2 diabetes leads to severe nocturnal hypoxemia, with an increase in apnea events and daytime sleepiness. Hence, we assessed sleep breathing parameters in the prediabetes stage. A cross-sectional study conducted on 966 middle-aged subjects without known pulmonary disease (311 patients with prediabetes and 655 controls with normal glucose metabolism) was conducted. Prediabetes was defined by glycated hemoglobin (HbA1c), and a nonattended overnight home sleep study was performed. Participants with prediabetes (n = 311) displayed a higher apnea–hypopnea index (AHI: 12.7 (6.1;24.3) vs. 9.5 (4.2;19.6) events/h, p < 0.001) and hypopnea index (HI: 8.4 (4.0;14.9) vs. 6.0 (2.7;12.6) events/h, p < 0.001) than controls, without differences in the apnea index. Altogether, the prevalence of obstructive sleep apnea was higher in subjects with prediabetes than in controls (78.1 vs. 69.9%, p = 0.007). Additionally, subjects with prediabetes presented impaired measurements of the median and minimum nocturnal oxygen saturation, the percentage of time spent with oxygen saturations below 90%, and the 4% oxygen desaturation index in comparison with individuals without prediabetes (p < 0.001 for all). After adjusting for age, sex, and the presence of obesity, HbA1c correlated with the HI in the entire population (r = 0.141, p < 0.001), and the presence of prediabetes was independently associated with the AHI (B = 2.20 (0.10 to 4.31), p = 0.040) as well as the HI (B = 1.87 (0.61 to 3.14), p = 0.004) in the multiple linear regression model. We conclude that prediabetes is an independent risk factor for an increased AHI after adjusting for age, sex, and obesity. The enhanced AHI is mainly associated with increments in the hypopnea events.

Influencing Factors of Daytime Sleepiness in Patients with Obstructive Sleep Apnea Hypopnea Syndrome and Its Correlation with Pulse Oxygen Decline Rate.

Objective To explore the influencing factors of daytime sleepiness in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and the correlation between daytime sleepiness and pulse oxygen decline rate in patients with severe OSAHS. Methods From January 2018 to April 2021, 246 consecutive patients with OSAHS diagnosed by polysomnography (PSG) in our hospital were selected. All patients were grouped according to the minimum nocturnal oxygen saturation and apnea hypopnea index (AHI). There were 33 cases in the no sleep hypoxia group, 34 cases in the mild hypoxia group, 119 cases in the moderate hypoxia group, and 60 cases in the severe hypoxia group. There were 30 cases in the simple snoring group, 55 cases in the mild OSAHS group, 48 cases in the moderate OSAHS group, and 113 cases in the severe OSAHS group. The Epworth Sleepiness Scale (ESS) scores of each group were compared. All patients were grouped according to ESS score. Those with score ≥9 were included in the lethargy group (n = 118), and those with score ≤10 were included in the no lethargy group (n = 128). Univariate and multivariate logistic regression analyses were used to explore the influencing factors of daytime sleepiness in OSAHS patients. Pearson correlation analysis showed the correlation between ESS score and pulse oxygen decline rate in patients with severe OSAHS. Results The ESS score of the severe hypoxia group > the moderate hypoxia group > the mild hypoxia group > the no sleep hypoxia group. There was significant difference among the groups (F = 19.700, P < 0.0001). There were significant differences between the severe hypoxia group and other groups and between the moderate hypoxia group and the no sleep hypoxia group and the mild hypoxia group (P < 0.05). The ESS score of the severe OSAHS group > the moderate OSAHS group > the mild OSAHS group > the simple snoring group. There was significant difference among the groups (F = 19.000, P < 0.0001). There were significant differences between the severe OSAHS group and other groups and between the moderate OSAHS group and the simple snoring group (P < 0.05). Univariate analysis showed that BMI, neck circumference, snoring degree, total apnea hypopnea time, AHI, micro arousal index (MAI), oxygen saturation (CT90%), lowest oxygen saturation (LSaO2), and mean oxygen saturation (MSaO2) were the influencing factors of daytime sleepiness in OSAHS patients (P < 0.05). Multiple logistic regression analysis showed that AHI and CT90% were independent risk factors for daytime sleepiness in OSAHS patients (P < 0.05). Pearson correlation analysis showed that there was a positive correlation between ESS score and pulse oxygen decline rate in patients with severe OSAHS (r = 0.765, P < 0.0001). Conclusion OSAHS patients may be accompanied by daytime sleepiness in varying degrees, which may be independently related to AHI and CT90%. The degree of daytime sleepiness in patients with severe OSAHS may be closely related to the decline rate of pulse oxygen, which should be paid great attention in clinic.

Prevalence of Cardiovascular Events and Their Risk Factors in Patients With Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea Overlap Syndrome.

Rationale: Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) have been identified as independent risk factors for cardiovascular diseases. However, the impact of COPD and OSA overlap syndrome (OS) on cardiovascular outcomes remains to be elucidated.Objective: To determine the prevalence of cardiovascular events and their risk factors in OS patients.Methods: Seventy-four patients who had OS between January 2015 and July 2020 were retrospectively enrolled, and 222 COPD-only patients and 222 OSA-only patients were pair-matched for age and sex from the same period and served as the OS-free control group. The prevalence rates of coronary heart disease (CHD), arrhythmia, heart failure, and pulmonary arterial hypertension (PAH) were compared among the three groups, and multivariable logistic regression models were used to screen the risk factors for specific cardiovascular events.Results: OS patients had higher prevalence rates of heart failure (10.8 vs. 0.5 and 1.4%, respectively) and PAH (31.1 vs. 4.5 and 17.1%, respectively) than those with OSA alone or COPD alone (all P < 0.01). The CHD prevalence was also significantly higher in the OS group than in the COPD-alone group (25.7 vs. 11.7%, P < 0.01). There was no significant difference in the prevalence of arrhythmia among the three groups (20.3, 22.5, and 13.1%, respectively, P > 0.05). In OS patients, risk factors for CHD included hypertension, diabetes, body mass index, lactate dehydrogenase level, and tidal volume; risk factors for heart failure included diabetes, partial pressure of oxygen, partial pressure of carbon dioxide, maximum ventilatory volume, and neutrophilic granulocyte percentage; and risk factors for PAH included minimum nocturnal oxygen saturation, partial pressure of carbon dioxide, and brain natriuretic peptide and lactate dehydrogenase levels.Conclusions: OS patients have a higher prevalence of cardiovascular events, which is associated with hypoxemia, hypercapnia, and impaired lung function in these patients.

A novel parameter is better than the AHI to assess nocturnal hypoxaemia and excessive daytime sleepiness in obstructive sleep apnoea

To evaluate whether the percentage of total sleep time spent with apnoea and hypopnoea duration time (AHT%) is better than the apnoea-hypopnoea index (AHI) for the assessment of nocturnal hypoxaemia and excessive daytime sleepiness (EDS) in patients with obstructive sleep apnoea (OSA). Patients with suspected OSA were enrolled. Polysomnography, Epworth Sleepiness Scale, self-administered surveys and anthropometric measures were performed. The efficiency of AHT% and the AHI was evaluated for nocturnal hypoxaemia and EDS. A total of 160 eligible participants were analysed. The median AHT% in normal, mild, moderate and severe OSA patients was significantly different in the four-group patients with OSA. Spearman rank correlations analysis found that the associations were stronger between AHT% with percentage of total sleep time and O2 saturation of < 90% and minimum nocturnal oxygen saturation than these parameters with the AHI. AHT% had a greater area under the curve than the AHI for predicting EDS in patients with OSA. AHT% was significantly higher in the EDS group. We present a novel parameter, AHT%, to evaluate nocturnal hypoxaemia and EDS in OSA patients. AHT% partially compensates for the shortcomings of the AHI. AHT% is better than the AHI for assessing nocturnal hypoxaemia and EDS. AHT% reflects different clinical characteristics associated with OSA from a new perspective.

Obstructive sleep apnea increases heart rhythm disorders and worsens subsequent outcomes in elderly patients with subacute myocardial infarction.

OBJECTIVEObstructive sleep apnea (OSA) is a potential cardiovascular risk. We aimed to investigate the association of OSA with heart rhythm disorders and prognosis in elderly patients with new-onset acute myocardial infarction (AMI).METHODSWe prospectively enrolled 252 AMI elderly patients (mean age, 68.5 ± 6.9 years) who were undergoing revascularization and completed a sleep study during their hospitalization. All subjects were categorized into non-OSA (apnea–hypopnea index (AHI) < 15, n = 130) and OSA (AHI ≥ 15, n = 122) groups based on the AHI. The changes in the autonomic nervous system, incidence of arrhythmia during nocturnal sleep, and major adverse cardiovascular and cerebrovascular events (MACCEs) were compared between the groups. RESULTSThe mean AHI value in all AMI patients was 22.8 ± 10.9. OSA patients showed higher levels of body mass index and peak high-sensitivity C-reactive protein and lower levels of minimum nocturnal oxygen saturation (MinSaO2), as well as greater proportion of multivessel coronary artery disease (all P < 0.05). The OSA group also showed significant increases in heart rate variability and heart rate turbulence onset (both P < 0.05) and higher incidence of arrhythmia (including sinus, atrial, and ventricular in origin). At a median follow-up of 6 months (mean 0.8–1.6 years), OSA (AHI ≥ 15) combined with hypoxia (MinSaO 2 ≤ 80%) was independently associated with the incidence of MACCEs (hazard ratio [HR]: 4.536; 95% confidence interval [CI]: 1.461−14.084,P = 0.009) after adjusting for traditional risk factors. CONCLUSIONSOSA and OSA-induced hypoxia may correlate with the severity of myocardial infarction, increase the occurrence of heart rhythm disorders in elderly subacute MI patients, and worsen their short-term poor outcomes.

RELATIONSHIP BETWEEN SLEEP BREATHING PATTERNS AND BLOOD PRESSURE CHANGES DURING ACUTE HIGH ALTITUDE EXPOSURE. DATA FROM HIGHCARE STUDIES

Objective: Acute exposure to high/moderate altitude (HMA) induces increase in ambulatory blood pressure (BP), which may be particularly pronounced during the night, leading to reduced nocturnal BP dipping. Occurrence of central sleep apneas (CSA) is also typical for HMA exposure. Aim of this study was to investigate the relationship between variables characterizing respiration during sleep with nocturnal BP in subjects acutely exposed to HMA. Design and method: Aggregate data from several studies performed in the framework of HIGHCARE projects were analysed (HIGHCARE-Himalaya – 5400 m, Alps - 4559 m, Sestriere 2035 m, all in healthy volunteers; Andes – 3260 m, hypertensive subjects). HMA exposure duration ranged between 1 and 15 days. Data of subjects with at least 1 ambulatory BP monitoring at sea level (SL) and HMA (validated oscillometric device) and at least 1 cardio-respiratory sleep study (CSS) were analysed. Study variables included: mean nocturnal systolic(S) and diastolic (D)BP; size of nocturnal BP fall (%), apnea-hypopnea index (AHI), central apnea index (cAI), mean and minimum nocturnal oxygen saturation (SpO2mean and SpO2 min). Mixed linear models adjusting for age, sex, BMI, study, treatment were used to assess the relationship between variables of interest. Results: After excluding participants with incomplete data, 178 subjects were included (52.8% male, age 45.6 ± 11.7, BMI 25.3 ± 4.3). During HMA exposure we observed an increase in nocturnal SBP/DBP by 10.8 ± 12.9 mmHg, a reduction in nocturnal SBP/DBP fall by 2.5 ± 7.9%. Median SpO2mean was 82.6%, SpO2 min 70%, AHI 22.5, cAI 1.1. 82% of participants had AHI > 5. After adjusting for covariates no association was found between changes in nocturnal BP/dipping and AHI or cAI. We observed a direct relationship between SpO2mean and the change in nocturnal SBP fall (β=0.21 [0.04–0.39], p = 0.017). In categorical analysis participants who at HMA became nondippers (SBP fall < 10%) had lower SpO2mean than those who maintained nocturnal dipping (77.9 vs. 84.2%, adjusted p = 0.044). Conclusions: Attenuation of physiological nocturnal BP fall at HMA is associated with the degree of nocturnal hypoxemia but not with the severity of sleep breathing disorders induced by HMA exposure. These results may be relevant in conditions associated with nocturnal hypoxia and/or CSA.

Non-steady State Modeling of the Ventilatory Depressant Effect of Remifentanil in Awake Patients Experiencing Moderate-to-severe Obstructive Sleep Apnea.

Evidence suggests that obstructive sleep apnea promotes postoperative pulmonary complications by enhancing vulnerability to opioid-induced ventilatory depression. We hypothesized that patients with moderate-to-severe obstructive sleep apnea are more sensitive to remifentanil-induced ventilatory depression than controls. After institutional approval and written informed consent, patients received a brief remifentanil infusion during continuous monitoring of ventilation. We compared minute ventilation in 30 patients with moderate-to-severe obstructive sleep apnea diagnosed by polysomnography and 20 controls with no to mild obstructive sleep apnea per polysomnography. Effect site concentrations were estimated by a published pharmacologic model. We modeled minute ventilation as a function of effect site concentration and the estimated carbon dioxide. Obstructive sleep apnea status, body mass index, sex, age, use of continuous positive airway pressure, apnea/hypopnea events per hour of sleep, and minimum nocturnal oxygen saturation measured by pulse oximetry in polysomnography were tested as covariates for remifentanil effect site concentration at half-maximal depression of minute ventilation (Ce50) and included in the model if a threshold of 6.63 (P < 0.01) in the reduction of objective function was reached and improved model fit. Our model described the observed minute ventilation with reasonable accuracy (22% median absolute error). We estimated a remifentanil Ce50 of 2.20 ng · ml (95% CI, 2.09 to 2.33). The estimated value for Ce50 was 2.1 ng · ml (95% CI, 1.9 to 2.3) in patients without obstructive sleep apnea and 2.3 ng · ml (95% CI, 2.2 to 2.5) in patients with obstructive sleep apnea, a statistically nonsignificant difference (P = 0.081). None of the tested covariates demonstrated a significant effect on Ce50. Likelihood profiling with the model including obstructive sleep apnea suggested that the effect of obstructive sleep apnea on remifentanil Ce50 was less than 5%. Obstructive sleep apnea status, apnea/hypopnea events per hour of sleep, or minimum nocturnal oxygen saturation measured by pulse oximetry did not influence the sensitivity to remifentanil-induced ventilatory depression in awake patients receiving a remifentanil infusion of 0.2 μg · kg of ideal body weight per minute.

Predictors of obesity hypoventilation syndrome among patients with sleep-disordered breathing in India.

Introduction:No study has been done in India to evaluate obesity hypoventilation syndrome (OHS) among patients with sleep-disordered breathing (SDB). The known predictors of OHS, i.e., body mass index (BMI) >35 kg/m2 and forced vital capacity (FVC) <3.5 L for men and <2.3 L for women from western countries, cannot be applied to Indian patients.Objectives:To find out the prevalence of OHS and to determine the predictors of OHS among Indian SDB patients.Materials and Methods:It was a retrospective observational study conducted in a tertiary care institute from September 1, 2017, to August 31, 2018. All the patients who underwent polysomnography were analyzed for the presence of OHS. Of 85 patients referred for polysomnography, 76 had SDB. Thirteen patients were excluded because of hypoventilation due to other known causes or could not perform spirometry.Results:The prevalence of OHS among SDB after excluding the other causes of hypoventilation was 15.87% (10/63). The predictors were determined using univariate analysis between daytime partial pressure of carbon dioxide (PaCO2) and other predictors. PaCO2 significantly correlated with minimum nocturnal oxygen saturation by pulse oximetry (SpO2), FVC %predicted, BMI, daytime SpO2, forced expiratory volume %predicted, and partial pressure of oxygen (PaO2). Following a stepwise multiple regression, minimum nocturnal SpO2, FVC %predicted, and BMI were found to be independent predictors of OHS. A minimum nocturnal SpO2 threshold of 60%, FVC %predicted <74.5%, BMI >30.95 kg/m2, and absolute FVC <2.33 L for men and <1.68 L for women were found to be predictors of OHS.Conclusion:The prevalence of OHS in Indian patients is similar to Caucasians. OHS is seen in Indian patients even at a lower BMI and lower spirometric parameters.

19 Sleep-disordered breathing in heart failure patients requiring cardiac resynchronisation therapy: is there a link to poorer outcomes after device insertion

Rationale We sought to ascertain the burden of undiagnosed sleep-disordered breathing (SDB) in high-risk heart failure patients, namely patients requiring cardiac resynchronisation therapy (CRT). Additionally, we looked for correlation between presence of SDB and change in cardiac function pre- and post-device. Methods From a population of 40 patients with CRT devices implanted, a stable group of 18 were selected. Polysomnography was undertaken in each case. Apnoea-hypopnoea index (AHI), oxygen desaturation index (ODI), sleep efficiency, minimum oxygen saturation and snore index were calculated. Comparison was made to left ventricular function, left atrial dimension and mitral regurgitation severity pre- and post-implantation of CRT device. We also measured functional capacity of each patient using the International Physical Activity Questionnaire (IPAQ) tool and compared sleep profiled of those with a good functional capacity (>1000 MET minutes/week) against those with poor functional capacity. Data were analysed with simple descriptive statistics for baseline characteristics and comparisons made using Student t-test. Results Our population had a high AHI (mean 14.2) and ODI (15.2) with poor sleep efficiency (mean 62%). 2 patients (11%) were classified as severe OSA (AHI > 30), and 11 (61%) had mild to moderate OSA. Patients were subdivided into those with improved cardiac function post-implant (n = 8) and those with unchanged or disimproved function (n = 10). Those patients who had an objective improvement in cardiac function by echocardiographic parameters were found to have a better overall sleep profile with a lower AHI (6.8 vs 16.05), snore index (32.6 vs 49.95) and higher sleep efficiency (63% vs 61%) and minimum nocturnal oxygen saturation (88% vs 83%). Patients with poor functional capacity as identified by were additionally found to have a higher snore index (48.7 vs 26.9) and poorer sleep efficiency (48.7 vs 71.8). Conclusions There is a high prevalence of SDB in our cohort with a trend towards more severe sleep apnoea in non-responders to CRT. Failure to respond to appropriate device therapy in severe heart failure may be a red flag for clinicians, with identification and treatment of co-morbid sleep apnoea potentially having a role in optimising patient outcomes.

Early Major Medical Complications After Surgical Management of Obstructive Sleep Apnea: A Retrospective Cohort Analysis and Case Series

The purpose of this study was to determine the frequency and relative risk (RR) of early postoperative major medical complications after surgery for the management of obstructive sleep apnea. This was a retrospective cohort analysis of patients who had undergone surgery for the treatment of polysomnogram-confirmed obstructive sleep apnea at 2 hospitals in Pittsburgh, PA, between 1992 and 2013. Early postoperative major medical complications were defined as either a life-threatening complication requiring intensive care unit intervention or death within the immediate hospital course. Standard demographic data, apnea-hypopnea index, Epworth Sleepiness Score, minimum nocturnal oxygen saturation, and body mass index were collected. The 2-tailed independent t test, Fisher exact test, and RR with 95% confidence interval were used. A total of 267 consecutive patients who underwent surgery for obstructive sleep apnea and met the inclusion criteria were included in this study. A total of 6 patients (6 of 267, 2.2%) had early major medical postoperative complications. When stratified by surgical group (intrapharyngeal vs extrapharyngeal), there were 162 intrapharyngeal patients with 2 complications (1.2%) and 105 extrapharyngeal patients with 4 complications (3.8%). We found no statistically significant difference in frequency (2 of 162 intrapharyngeal patients [1.2%] vs 4 of 105 extrapharyngeal patients [3.8%], P = .17) or RR (3.1; 95% confidence interval, 0.58 to 16.55; P = .1885) between the groups. There were statistically significant differences for mean age, apnea-hypopnea index, Epworth Sleepiness Score, minimum nocturnal oxygen saturation, and body mass index between the surgical groups. The overall frequency of early major medical postoperative complications in upper airway surgery for obstructive sleep apnea is low, with no statistically significant difference in frequency and RR between intrapharyngeal and extrapharyngeal surgery. There may, however, be a clinically significance difference in RR possibly because of associated differences in risk factors between the groups.

Risk factors for, and prevalence of, sleep apnoea in cardiac rehabilitation facilities in Germany: The Reha-Sleep registry.

To determine the prevalence of, and the risk factors for, sleep apnoea in cardiac rehabilitation (CR) facilities in Germany. 1152 patients presenting for CR were screened for sleep-disordered breathing with 2-channel polygraphy (ApneaLink™; ResMed). Parameters recorded included the apnoea-hypopnoea index (AHI), number of desaturations per hour of recording (ODI), mean and minimum nocturnal oxygen saturation and number of snoring episodes. Patients rated subjective sleep quality on a scale from 1 (poor) to 10 (best) and completed the Epworth Sleepiness Scale (ESS). Clinically significant sleep apnoea (AHI ≥15/h) was documented in 33% of patients. Mean AHI was 14 ± 16/h (range 0-106/h). Sleep apnoea was defined as being of moderate severity in 18% of patients (AHI ≥15-29/h) and severe in 15% (AHI ≥30/h). There were small, but statistically significant, differences in ESS score and subjective sleep quality between patients with and without sleep apnoea. Logistic regression model analysis identified the following as risk factors for sleep apnoea in CR patients: age (per 10 years) (odds ratio (OR) 1.51; p<0.001), body mass index (per 5 units) (OR 1.31; p=0.001), male gender (OR 2.19; p<0.001), type 2 diabetes mellitus (OR 1.45; p=0.040), haemoglobin level (OR 0.91; p=0.012) and witnessed apnoeas (OR 1.99; p<0.001). The findings of this study indicate that more than one-third of patients undergoing cardiac rehabilitation in Germany have sleep apnoea, with one-third having moderate-to-severe SDB that requires further evaluation or intervention. Inclusion of sleep apnoea screening as part of cardiac rehabilitation appears to be appropriate.

Relation of the Severity of Obstructive Sleep Apnea in Response to Anti-Arrhythmic Drugs in Patients With Atrial Fibrillation or Atrial Flutter

Atrial fibrillation (AF) is more common in those with obstructive sleep apnea (OSA) than in unaffected subjects and recurs more frequently in the presence of severe OSA after electrical cardioversion and AF ablation. However, it is unknown whether the severity of OSA influences the efficacy of antiarrhythmic drug (AAD) therapy in patients with OSA and AF. The aim of this study was to examine the impact of OSA severity on the treatment of patients with symptomatic AF using AADs. Sixty-one patients (mean age 62 ± 15 years, 21 women) treated with AADs for symptomatic AF who underwent overnight polysomnography were studied. Rhythm control was prospectively defined as successful if a patient remained on the same AAD therapy for ≥6 months with ≥75% reduction in symptomatic AF burden. Twenty-four patients (40%) had severe OSA. Thirty patients (49%) were rhythm controlled with AADs. Nonresponders to AADs were more likely to have severe OSA than milder disease (52% vs 23%, p <0.05); those with severe OSA were less likely to respond to AADs than participants with nonsevere OSA (39% vs 70%, p = 0.02). Nonresponders had higher apnea-hypopnea indexes than responders (34 ± 25 vs 22 ± 18 events/hour, p = 0.05), but there were no differences between these groups in minimum oxygen saturation or percentage of time spent in rapid eye movement sleep. In conclusion, patients with severe OSA are less likely to respond to AAD therapy for AF than those with milder forms of OSA.

Consequences of Comorbid Sleep Apnea in the Metabolic Syndrome— Implications for Cardiovascular Risk

Metabolic syndrome (MetSyn) increases overall cardiovascular risk. MetSyn is also strongly associated with obstructive sleep apnea (OSA), and these 2 conditions share similar comorbidities. Whether OSA increases cardiovascular risk in patients with the MetSyn has not been investigated. We examined how the presence of OSA in patients with MetSyn affected hemodynamic and autonomic variables associated with poor cardiovascular outcome. Prospective clinical study. We studied 36 patients with MetSyn (ATP-III) divided into 2 groups matched for age and sex: (1) MetSyn+OSA (n = 18) and (2) MetSyn-OSA (n = 18). OSA was defined by an apnea-hypopnea index (AHI) > 15 events/hour by polysomnography. We recorded muscle sympathetic nerve activity (MSNA - microneurography), heart rate (HR), and blood pressure (BP - Finapres). Baroreflex sensitivity (BRS) was analyzed by spontaneous BP and HR fluctuations. MSNA (34 +/- 2 vs 28 +/- 1 bursts/min, P = 0.02) and mean BP (111 +/- 3 vs. 99 +/- 2 mm Hg, P = 0.003) were higher in patients with MetSyn+OSA versus patients with MetSyn-OSA. Patients with MetSyn+OSA had lower spontaneous BRS for increases (7.6 +/- 0.6 vs 12.2 +/- 1.2 msec/mm Hg, P = 0.003) and decreases (7.2 +/- 0.6 vs 11.9 +/- 1.6 msec/mm Hg, P = 0.01) in BP. MSNAwas correlated with AHI (r = 0.48; P = 0.009) and minimum nocturnal oxygen saturation (r = -0.38, P = 0.04). Patients with MetSyn and comorbid OSA have higher BP, higher sympathetic drive, and diminished BRS, compared with patients with MetSyn without OSA. These adverse cardiovascular and autonomic consequences of OSA may be associated with poorer outcomes in these patients. Moreover, increased BP and sympathetic drive in patients with MetSyn+OSA may be linked, in part, to impairment of baroreflex gain.

Long Term Effect of Autoadjusting Positive Airway Pressure on C-Reactive Protein and Interleukin-6 in Men With Obstructive Sleep Apnoea Syndrome

Background and objectives Obstructive sleep apnoea (OSA) has been increasingly linked to cardiovascular disease. Inflammatory processes associated with OSA may contribute to this morbidity. Some studies have reported serum levels of high sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) to be increased in these patients. Primary objective: investigate the impact of short and long-term autoadjusting positive airway pressure (APAP) therapy on IL-6 and hs-CRP serum levels in patients with moderate to severe obstructive sleep apnoea. Secundary Objective: evaluate the basal hs-CRP and IL-6 levels in OSA patients and its possible relation to OSA severity, independently of confounders and compare the hs-CRP levels in OSA patients with those in community controls. Patients and methods This is a prospective study including 98 male patients with moderate to severe OSA confirmed by domiciliary sleep study. Malignancy and chronic inflammatory diseases were exclusion criteria. hs-CRP and IL-6 serum levels were evaluated before APAP, 9 days and 6 months after therapy. Community controls (n=103) were selected using random digit dialling, and matched by age and body mass index (BMI) for comparison of hs-CRP levels at baseline. Results The studied population had a mean age of 55.3±10.7 years, mean BMI 33.2±5.0kg/m2, mean apnoeahypopnoea index 51.7±21.3/h and mean desaturation index 86.3±5.3/h. The APAP compliance was good: 91.27&%×000B1;20.45 days usage and 5.76±1.59h/night of usage. Mean basal hs-CRP and IL-6 serum values were 0.52±0.53 μg/l and 17.7±22.5 μg/l, respectively. CRP levels at baseline correlated significantly with apnoea-hypopnoea index, desaturation index and minimum nocturnal oxygen saturation. IL-6 levels at baseline correlated significantly and negatively with minimum nocturnal oxygen saturation. When adjusting for confounding factors found in this study, all these relations lost significance. CRP is significantly increased in patients when compared to controls ( P=.002) and when considering hs-CRP cardiovascular risk stratified categories, cases had significantly more patients at high risk of cardiovascular events than controls ( P=.002). After adjustment for BMI and arterial hypertension, cases had an almost twofold moderate risk of cardiovascular events and more than a twofold severe risk of cardiovascular events when compared to controls. We found no significant difference between hs-CRP and IL-6 concentrations pre-treatment and in two moments post-treatment (9 days and 6 months) (CRP: P=.720 and P=.387, respectively; IL-6: P=.266 and P=.238, respectively). Conclusions OSA is associated with a low-grade inflammatory process; hs-CRP serum levels are elevated in OSA patients when comparing to community controls, independently of age and BMI and the former have a significantly higher risk of cardiovascular events when compared to the latter. There was no significant decrease of both inflamatory mediators (hs-CRP, IL-6) after short and long-term APAP therapy.

Efecto a largo plazo de la presión positiva automática en la vía aérea sobre la proteína C reactiva y la interleucina-6 en varones con síndrome de apnea obstructiva del sueño

Background and objectives Obstructive sleep apnoea (OSA) has been increasingly linked to cardiovascular disease. Inflammatory processes associated with OSA may contribute to this morbidity. Some studies have reported serum levels of high sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) to be increased in these patients. Primary objective: investigate the impact of short and long-term autoadjusting positive airway pressure (APAP) therapy on IL-6 and hs-CRP serum levels in patients with moderate to severe obstructive sleep apnoea. Secundary Objective: evaluate the basal hs-CRP and IL-6 levels in OSA patients and its possible relation to OSA severity, independently of confounders and compare the hs-CRP levels in OSA patients with those in community controls. Patients and methods This is a prospective study including 98 male patients with moderate to severe OSA confirmed by domiciliary sleep study. Malignancy and chronic inflammatory diseases were exclusion criteria. hs-CRP and IL-6 serum levels were evaluated before APAP, 9 days and 6 months after therapy. Community controls (n=103) were selected using random digit dialling, and matched by age and body mass index (BMI) for comparison of hs-CRP levels at baseline. Results The studied population had a mean age of 55.3±10.7 years, mean BMI 33.2±5.0 kg/m 2, mean apnoea-hypopnoea index 51.7±21.3/h and mean desaturation index 86.3±5.3/h. The APAP compliance was good: 91.27%±20.45 days usage and 5.76±1.59 h/night of usage. Mean basal hs-CRP and IL-6 serum values were 0.52±0.53 μg/l and 17.7±22.5 μg/l, respectively. CRP levels at baseline correlated significantly with apnoea-hypopnoea index, desaturation index and minimum nocturnal oxygen saturation. IL-6 levels at baseline correlated significantly and negatively with minimum nocturnal oxygen saturation. When adjusting for confounding factors found in this study, all these relations lost significance. CRP is significantly increased in patients when compared to controls (p=0.002) and when considering hs-CRP cardiovascular risk stratified categories, cases had significantly more patients at high risk of cardiovascular events than controls (p=0.002). After adjustment for BMI and arterial hypertension, cases had an almost twofold moderate risk of cardiovascular events and more than a twofold severe risk of cardiovascular events when compared to controls. We found no significant difference between hs-CRP and IL-6 concentrations pre-treatment and in two moments post-treatment (9 days and 6 months) (CRP: p=0.720 and p=0.387, respectively; IL-6: p=0.266 and p=0.238, respectively). Conclusions OSA is associated with a low-grade inflammatory process; hs-CRP serum levels are elevated in OSA patients when comparing to community controls, independently of age and BMI and the former have a significantly higher risk of cardiovascular events when compared to the latter. There was no significant decrease of both inflamatory mediators (hs-CRP, IL-6) after short and long-term APAP therapy.

Why does gender influence survival in obstructive sleep apnoea?

The study aim was to compare the mortality risk of men and women diagnosed with obstructive sleep apnoea (OSA) and started on treatment with continuous positive airway pressure (CPAP). From August to December 2003 we reviewed the hospital records of patients who had started on CPAP for OSA between July 1995 and June 1998. Mortality rates were compared between men and women. Associations with mortality risk were determined using univariate and multivariate Cox's proportional hazards regression. The sample comprised 292 men and 47 women. Eight percent of the men and 23% of the women died (p=0.003). Univariate analysis showed increased mortality risk was associated with female sex, greater age when CPAP was started, a pre-treatment minimum nocturnal oxygen saturation (SpO(2)) <75%, a higher Charlson comorbidity index score and discontinuation of CPAP treatment. Female sex remained associated with increased mortality independent of age, minimum SpO(2) and CPAP use, but was not independent of the Charlson score. Women diagnosed with OSA and treated with CPAP demonstrated a 3.44 greater mortality risk than men, mostly due to greater comorbidity.

Predictive Factors of Quality-of-Life Improvement and Continuous Positive Airway Pressure Use in Patients With Sleep Apnea-Hypopnea Syndrome: Study at 1 Year

To assess predictive factors of quality-of-life (QoL) improvement and continuous positive airway pressure (CPAP) use in patients with sleep apnea-hypopnea syndrome (SAHS) after 1 year of treatment with CPAP. Observational, prospective cohort study. Sleep unit in a university hospital. One hundred thirty-three consecutive patients with an indication for CPAP treatment. Nottingham health profile (NHP) questionnaire, Epworth sleepiness scale score, and objective CPAP use (time counter in the CPAP device) were assessed at baseline and after 3 months and 12 months of CPAP use. Multivariate logistic regression was used to identify predictive factors of CPAP use and improved QoL. At 1 year, 101 patients (76%) were still using CPAP; of these, 88 patients (66%) completed all the follow-up questionnaires. QoL was lower before treatment, compared with the general population, and all dimensions of the NHP, except social isolation, improved significantly from baseline in patients regularly using CPAP, reaching levels comparable to those of the general population at 1 year. Only minimum oxyhemoglobin saturation at diagnostic polysomnography was associated with the degree of QoL improvement at 1 year. Only the NHP and the apnea-hypopnea index (AHI) at baseline were significantly associated with hours of CPAP use at 1 year. Compared to the general population, patients with untreated SAHS had a lower QoL, which improved to the level of the general population after 3 months of CPAP therapy and persisted at 1 year of treatment with CPAP. The only predictor of QoL improvement was minimum nocturnal oxygen saturation at baseline. Higher AHI and worse QoL at baseline were predictors of hours of CPAP use.