Median Apnea-hypopnea Index Research Articles

Obstructive Sleep Apnea and Diabetic Neuropathy

Diabetic peripheral neuropathy is common and causes significant morbidity. Obstructive sleep apnea (OSA) is also common in patients with type 2 diabetes. Because OSA is associated with inflammation and oxidative stress, we hypothesized that OSA is associated with peripheral neuropathy in type 2 diabetes. To assess the relationship between OSA and peripheral neuropathy in patients with type 2 diabetes. A cross-sectional study of adults with type 2 diabetes recruited randomly from the diabetes clinic of two UK hospitals. Peripheral neuropathy was diagnosed using the Michigan Neuropathy Screening Instrument. OSA (apnea-hypopnea index ≥ 5 events/h) was assessed using home-based, multichannel respiratory monitoring. Serum nitrotyrosine was measured by ELISA, lipid peroxide by spectrophotometer, and microvascular function by laser speckle contrast imaging. Two hundred thirty-four patients (mean [SD] age, 57 [12] yr) were analyzed. OSA prevalence was 65% (median apnea-hypopnea index, 7.2; range, 0-93), 40% of which were moderate to severe. Neuropathy prevalence was higher in patients with OSA than those without (60% vs. 27%, P < 0.001). After adjustment for possible confounders, OSA remained independently associated with diabetic neuropathy (odds ratio, 2.82; 95% confidence interval, 1.44-5.52; P = 0.0034). Nitrotyrosine and lipid peroxide levels (n = 102, 74 with OSA) were higher in OSA and correlated with hypoxemia severity. Cutaneous microvascular function (n = 71, 47 with OSA) was impaired in OSA. We describe a novel independent association between diabetic peripheral neuropathy and OSA. We identified increased nitrosative/oxidative stress and impaired microvascular regulation as potential mechanisms. Prospective and interventional studies are needed to assess the impact of OSA and its treatment on peripheral neuropathy development and progression in patients with type 2 diabetes.

Use of SPECT to detect changes in diastolic and coronary reserve in patients with obstructive sleep apnea

To assess diastolic function and coronary artery reserve in patients with obstructive sleep apnea (OSA) using single-photon emission computer tomography (SPECT). Patients with OSA who had normal echocardiograph/electrocardiogram findings were divided into three groups based on OSA severity: mild (n = 15), moderate (n = 13), or severe (n = 18). A control group of participants without OSA (n = 17) was included. SPECT (with technetium-99 m-labeled red blood cells) was performed after the induction of cardiac stress by injection of dobutamine. The following ventricular parameters were determined: left ventricular ejection fraction, peak filling rate (PFR), peak ejection rate, 1/3 filling fraction (1/3FF), and regional ejection fractions (rEF). The median ages of OSA and control participants were 45.0 and 51.0 years, respectively. Median apnea-hypopnea index scores were 3.3, 9.1, 38.5, and 65.2 for the control, mild OSA, moderate OSA, and severe OSA groups, respectively. Post-stress, 1/3FF was significantly lower in the overall OSA group compared with the control group (P < 0.05). PFR was significantly lower in the overall OSA group compared with the control group (P < 0.05) and was significantly lower in the severe OSA group compared with the mild OSA group. Regional ejection fractions rEF3 (cardiac apex and a small part of the inferior wall) and rEF4 (anteroseptal wall) were significantly lower in the overall OSA group compared with the control group, suggesting decreased coronary artery reserve. Our findings suggest that SPECT can be used to detect abnormalities in diastolic function and coronary reserve in patients with OSA who have normal electrocardiogram or echocardiograph findings. SPECT may be useful for the early detection of cardiovascular disease in patients with OSA.

Differential effects of sleep disordered breathing on polysomnographic characteristics in preschool and school aged children

Childhood sleep disordered breathing (SDB) peaks in the preschool years. We aimed to compare the effects of SDB on polysomnographic characteristics between preschool and school aged children. One hundred and fifty-two preschool (3-5 y) and 105 school-aged (7-12 y) children, referred for assessment of SDB, plus controls (39, 3-5 y and 34, 7-12 y) with no history of snoring underwent overnight polysomnography. Subjects were grouped by their obstructive apnea hypopnea index (AHI) into those with primary snoring, mild obstructive sleep apnea (OSA), and moderate/severe OSA. The effects of SDB severity on sleep architecture and respiratory characteristics were compared between the age cohorts using quantile regression. There was an average reduction in median sleep efficiency of 3.5% (p=0.004) and an average increase in median WASO of 2% (p=0.08) between the age cohorts across the severity groups, with sleep efficiency falling and WASO increasing with increasing SDB severity in the school-aged, but not the preschool, cohort. There was an average difference in median central AHI of 0.6 events/h (p<0.001) between the age cohorts across the severity groups, with the 3-5 y old cohort but not the 7-12 y old cohort having more central apneas with increasing SDB severity. We have demonstrated clinically important, age-related differences in sleep architecture in children with SDB. Preschool children with SDB maintain sleep efficiency and awaken fewer times throughout the night than do school aged children with a comparable severity of SDB, but experience more central apneas. This may have implications for the outcomes and treatment of SDB in children of different ages.

The Effect of Positional Dependency on Outcomes of Treatment With a Mandibular Advancement Device

To evaluate retrospectively the efficacy of the mandibular advancement device (MAD) in patients with obstructive sleep apnea in terms of positional dependency. Retrospective analysis. Academic tertiary referral center. One hundred patients with obstructive sleep apnea treated with the MAD at the Department of Otorhinolaryngology sleep clinic were included from January 1, 2005, through December 31, 2010. All patients underwent nocturnal full-night polysomnography before and at least 3 months after intraoral MAD application. Treatment results and prognostic factors deciding the success of MAD application. Of the 100 patients, 80 showed positional dependency and 20 showed nondependency. In the position-dependent obstructive sleep apnea group, the median (interquartile range) apnea-hypopnea index (AHI) decreased from 32.1 (24.4-41.9) to 8.6 (3.7-13.8) (P < .001); in the nondependent group, from 56.4 (26.2-71.5) to 15.7 (6.8-30.7) (P < .001). The success rate (AHI reduction ≥50% and AHI <10) was 57.5% and 30.0% in position-dependent and position-nondependent groups, respectively (P = .04). Identifying patients with obstructive sleep apnea as position dependent or nondependent may have important therapeutic implications in predicting the outcome of MAD treatment.

Clinical predictors of apnoea‐hypopnoea during propofol sedation in patients undergoing spinal anaesthesia*

This study assessed the relationship between the occurrence of apnoea-hypopnoea during propofol sedation for spinal anaesthesia and two different predictive tests of sleep apnoea: the STOP-Bang score (snoring while sleeping, daytime tiredness, observed breathing stoppages, high blood pressure-body mass index, age, neck circumference, gender); and the obstructive sleep apnoea (OSA) score. Thirty-four middle-aged men not diagnosed with obstructive sleep apnoea received propofol infusions adjusted to produce a bispectral index of 70-75. ApnoeaLink(TM) was used to estimate the incidence of apnoea-hypopnoea. The median (IQR [range]) apnoea-hypopnoea index was 17 (8-24 [0-70]) events.h(-1) and correlated weakly with the STOP-Bang score (p = 0.022, r = 0.423) and moderately with the OSA score (p < 0.001, r = 0.693). Severe apnoea-hypopnoea developed more frequently in patients with a higher OSA score (34.5% vs 0%) or higher STOP-Bang score (27.6% vs 6.9%). Both assessment tools have some predictive value for the occurrence of apnoea-hypopnoea during propofol sedation in patients undergoing spinal anaesthesia.

Serum S100B protein: a useful marker in obstructive sleep apnea syndrome

Background and purposeWe aimed to underline the importance of serum S100B protein as a useful biochemical marker in patients with obstructive sleep apnea syndrome (OSAS). Material and methodsForty-three newly diagnosed patients with OSAS (median apnea-hypopnea index [AHI, events/hour]: 37.5 [range 11.3–137]) and 25 subjects with AHI < 5 (median AHI: 4.4 [range 0.7–4.8]) were included in the study. Serum S100B protein level was tested in serum samples taken after polysomnography in both groups and the difference between OSAS patients and the control group regarding that level was assessed. In addition, the association of S100B protein serum level with age, body mass index, AHI, mean O2 saturation percentage during sleep, minimum O2 saturation value (%) at the end of the apneas, and the time spent at an O2 saturation less than 90% were analyzed in the OSAS patient group. ResultsMedian serum S100B protein level was 133.7 pg/mL (range 20.97–230.70 pg/mL) in patients with OSAS and 16.1 pg/mL (range 10.1–22.9 pg/mL) in the control group (p < 0.005). Serum S100B protein level did not correlate with any studied variable (p > 0.05 for each correlation coefficient). ConclusionsSerum S100B protein level is increased in patients with OSAS and may be a useful biochemical marker in those patients.

Increased serum levels of advanced glycation end-products is associated with severity of sleep disordered breathing but not insulin sensitivity in non-diabetic men with obstructive sleep apnoea

Patients with diabetes mellitus are known to have increased serum levels of advanced glycation end-products (AGEs), and this is also associated with insulin resistance. This study aimed to investigate the relationship between serum AGEs and insulin sensitivity in non-diabetic subjects with obstructive sleep apnoea (OSA). Adult males with no known comorbidities were recruited from the sleep clinic of a university teaching hospital. They underwent overnight in-laboratory polysomnography. Fasting blood was taken to measure serum AGE and plasma glucose levels. Insulin sensitivity was estimated using the short insulin tolerance test. In total, 105 subjects with a mean age of 43.5 (standard deviation [SD] 9.2)years, mean body mass index of 27.1 (SD 4.0)kg/m(2), and median apnoea-hypopnoea index (AHI) of 17 (interquartile range 5-46) were analysed. Serum AGE levels were significantly higher in subjects with OSA (AHI ≥5), compared with those without OSA (AHI <5) (3.9 [SD 1.2] vs. 3.2 [SD 0.8]μg/ml, respectively; P=0.037) after adjusting for confounders. AGE levels were positively correlated with AHI (r=0.318, P=0.001), but not with insulin sensitivity. AGE levels decreased in subjects with moderate-to-severe OSA who received continuous positive airway pressure (CPAP) treatment for three months (n=18, P=0.017). Serum AGE levels correlate with AHI in non-diabetic adult males. This relationship cannot be explained by insulin sensitivity. Supporting the hypothesis of a direct relationship between AHI and AGEs, AGE levels were found to decline with CPAP therapy.

Effect of Mild, Asymptomatic Obstructive Sleep Apnea on Daytime Heart Rate Variability and Impedance Cardiography Measurements

Dysregulation of autonomic nervous system dynamics is important in the pathophysiology of cardiovascular risk in obstructive sleep apnea (OSA). Heart rate variability (HRV) and impedance cardiography measures can estimate autonomic activity but have not gained traction clinically. The hypothesis of this study was that even in a cohort of patients with mild, asymptomatic OSA without overt cardiovascular disease, daytime HRV metrics and impedance cardiography measurements of preejection period would demonstrate increased sympathetic and decreased parasympathetic modulation compared to matched controls. Obese subjects (body mass index ≥30 kg/m(2)) without any known cardiovascular or inflammatory co-morbidities were recruited from the community. Subjects underwent standard in-laboratory polysomnography followed by simultaneous electrocardiographic and impedance cardiographic recordings while supine, supine with paced breathing, and after standing. Seventy-four subjects were studied, and 59% had OSA (apnea-hypopnea index ≥10 events/hour), with a median apnea-hypopnea index of 25.8 events/hour. Subjects with OSA had significantly decreased daytime time- and frequency-domain HRV indexes, but not significantly different preejection periods, compared to controls. Apnea-hypopnea index was a significant independent predictor of time-domain HRV measures in all awake conditions, after controlling for age, gender, blood pressure, fasting cholesterol levels and glycosylated hemoglobin. In conclusion, these results demonstrate reductions in cardiac vagal modulation, as measured by multiple daytime time-domain markers of HRV, in patients with asymptomatic OSA compared to controls. Further prospective outcomes-based studies are needed to evaluate the applicability of these metrics for noninvasive screening of obese patients with asymptomatic OSA, before the onset of overt cardiovascular disease.

Difference in dental arch size between obese and non‐obese patients with obstructive sleep apnoea

A large tongue is recognised as a factor that increases the collapsibility of the upper airway in obstructive sleep apnoea (OSA) patients. We hypothesised that the propensity to develop severe OSA could be minimised if the dental arches were enlarged in obese OSA people who are thought to have a large tongue. We therefore compared the size of the dental arches in obese and non-obese OSA patients. Using a lateral cephalogram and study models, we compared the sizes of the tongue and dental arches in 23 obese and 23 non-obese Japanese male OSA patients, who were matched for age, apnoea hypopnea index (AHI) and maxillomandibular size. The median age (years) and AHI (events per hour) for the obese and non-obese groups were 36·5 and 39·0, and 13·4 and 14·3, respectively. The maxillomandibular size was matched with regard to SNA, SNB and lower face cage obtained from cephalometric measurements. The parameters that were measured for the study model included dental arch width, dental arch length, overjet and overbite. Tongue size (P < 0·05) and both upper (P < 0·01) and lower (P < 0·05) dental arch widths were significantly larger in obese than in non-obese OSA patients, and there was no difference in the severity of OSA between the two groups. These findings suggest that the tongue was larger and dental arches were enlarged in obese patients compared with non-obese patients under the same disease severity. Wider dental arches in obese OSA patients may help to offset the impact of the enlarged tongue on upper airway patency.

Risk factors for post-operative complications in Chinese children with tonsillectomy and adenoidectomy for obstructive sleep apnea syndrome

Tonsillectomy and adenoidectomy (T&A) is commonly performed in children with obstructive apnea syndrome (OSAS). It was our hospital practice to observe all patients post T&A in the pediatric intensive care unit. We aim to describe the post-operative complications after tonsillectomy and adenoidectomy in children with OSAS and to identify risk factors for these complications. Medical records of patients from 1 to 16 years old with OSAS and T&A done in this department were retrieved for analysis from April 1999 to July 2006. Information of the individual patients including the demographic data, polysomnography data, and presence of post-operative complications were recorded and analyzed. A total of 86 patient records were analyzed (M/F = 69:17). The mean BMI z score was 1.13 ± 1.53, and 36% of patients were classified as obese with z > 1.96. The median apnea-hypopnea index (AHI) before T&A was 9.8 episodes/h. Only six patients had post-operative desaturation. No bleeding complications were reported in our cohort. It was found that patients with desaturation after T&A had significantly higher mean BMI z score than children without desaturation (p = 0.014). There was otherwise no significant difference between the age, sex, AHI score, and the history of allergic rhinitis or asthma between the two groups. Our results showed that most children with OSAS underwent T&A without complications. The respiratory complication rate was 7%, and desaturation was the most common post-operative complication. Children with higher BMI z score were more likely to have desaturation after T&A (p = 0.014). Hence, careful monitoring with pulse oximeter after T&A should be offered to those who are obese.

Cardiac Arrhythmias in Obstructive Sleep Apnea (from the Akershus Sleep Apnea Project)

Increased prevalence of cardiac arrhythmias has been reported in patients with severe obstructive sleep apnea (OSA), but this may not be generalizable to patients from the general population with a milder form of the condition. The aim of this study was to assess the association between cardiac arrhythmias and OSA of mainly mild and moderate severity. In total, 486 subjects (mean age 49 years, 55% men) recruited from a population-based study in Norway underwent polysomnography for OSA assessment and Holter recordings for arrhythmia assessment. Of these, 271 patients were diagnosed with OSA (apnea-hypopnea index [AHI] ≥5, median AHI 16.8, quartiles 1 to 3 8.9 to 32.6). Mean nadir oxygen saturations were 82% and 89% in patients with and without OSA, respectively. Ventricular premature complexes (≥5/hour) were more prevalent in subjects with OSA compared to subjects without OSA (median AHI 1.4, quartiles 1 to 3 0.5 to 3.0) during the night (12.2% vs 4.7%, p = 0.005) and day (14% vs 5.1%, p = 0.002). In multivariate analysis after adjusting for relevant confounders, AHI was independently associated with an increased prevalence of ventricular premature complexes at night (odds ratio per 1-U increase of log-transformed AHI 1.5, 95% confidence interval 1.1 to 2.0, p = 0.008) and during the day (odds ratio 1.37, 95% confidence interval 1.0 to 1.8, p = 0.035). In conclusion, the prevalence of ventricular premature complexes is increased in middle-aged patients with mainly mild or moderate OSA, suggesting an association between OSA and ventricular arrhythmias even in mild OSA.

Controlled, prospective trial of psychosocial function before and after mandibular advancement splint therapy

The aim of the study was to investigate psychosocial function in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS), before and after mandibular advancement splint (MAS) therapy. In a prospective, parallel-group study, changes in psychosocial scores were compared before and after MAS therapy for OSAHS. Patients from the top (MAS treated, n = 40) or bottom (conservatively treated n = 35) of a MAS waiting list rated quality of life (Short Form 36 [SF-36] Health Survey) and sleepiness (Epworth Sleepiness Scale [ESS]). Both groups' ratings at baseline were completed while on conservative therapy. Baseline variables did not differ between groups. At follow-up, psychosocial scores showed improvement in MAS-treated patients, with odds ratios (confidence interval) of 0.26 (0.09, 0.75) and 0.36 (0.14, 0.92) for sleepiness and energy/vitality domain, respectively. Statistically significant improvement in the median (range) sleepiness score (10 [1 to 18] to 6 [1 to 14]; P <0.001) and energy/vitality domain (18 [7 to 20] to 19 [14 to 20]; P = 0.03) were observed with MAS therapy. Reductions were detected in median apnea-hypopnea index (median [range] 16 [5.2 to 30] to 4.6 [0.8 to 17.2] events/hour; P <0.001), and oxygen desaturation index (ODI) (11 [3 to 16] to 0 [0 to 5] events/hour; P <0.001) at follow-up with MAS therapy. Similar changes were observed in the comparison group when they went on to be treated with MAS. This study demonstrated that treatment with MAS produced statistically and clinically significant psychosocial and cardio-respiratory improvements.

Comparison of full versus short induced-sleep polysomnography for the diagnosis of sleep apnea

Polysomnography (PSG) is the gold-standard method for diagnosing obstructive sleep apnea (OSA). However, the gap between demand and capacity in performing PSG is a major health-care problem. We sought to validate a short day-time induced sleep for the diagnosis of OSA. Prospective diagnostic method validation. We studied 25 consecutive patients referred to the sleep laboratory and 15 healthy volunteers. All subjects were evaluated by means of full overnight PSG (Full-PSG) and short day-time induced-sleep PSG (Induced-PSG). Sleep was monitored during both procedures (Embla, 16 channels). Sleep was induced by slow intravenous drip infusion of midazolam. The population studied (N = 40) was 60% male (mean age, 42 ± 10 years; body mass index, 29 ± 6.5 kg/m(2)). Sleep was successfully induced in all subjects, and no complications were observed (midazolam doses, 6.2 ± 3.8 mg; time of induced sleep 41.5 ± 18.9 minutes). The apnea-hypopnea index (AHI) and minimal oxygen saturation during Full-PSG versus Induced-PSG were similar: median AHI (with 25%-75% interquartile range) was 13 (3-35) events per hour versus 17 (4-36) events per hour, and median oxygen saturation was 84% (75-90) versus 85% (76-92); P = .89 and P = .53, respectively. The majority of the respiratory events during induced sleep were obstructive and similar to those observed during Full-PSG. AHI and lowest oxygen saturation during Induced-PSG correlated significantly with Full-PSG (r = 0.67 and r = 0.77, respectively). Sensitivity and specificity for the diagnosis of OSA (AHI > 15 events per hour) by Induced-PSG were 0.83 and 0.72, respectively. Induced-PSG by midazolam during the day is safe and correlates with Full-PSG; it therefore is a promising alternative method in the diagnosis of OSA.

The Influence of Intermittent Hypoxemia on Platelet Activation in Obese Patients with Obstructive Sleep Apnea

Literature regarding platelet function in obstructive sleep apnea (OSA) has considerable limitations. Given the central role of platelets in atherothrombosis and the known cardiovascular risk of OSA, we hypothesized that OSA severity is predictive of platelet function, independent of known comorbidities. Obese subjects, without comorbidities, underwent overnight, in-lab polysomnography. The following morning, 5 biomarkers of platelet activation were measured by whole-blood flow cytometry at baseline and in response to agonists (no stimulation, stimulation with 5 μM ADP agonist, and stimulation with 20 μM ADP agonist): platelet surface P-selectin, activated glycoprotein (GP) IIb/IIIa, and GPIb receptor expression, platelet-monocyte aggregation (PMA) and platelet-neutrophil aggregation (PNA). Of the 77 subjects, 47 were diagnosed with OSA (median apnea-hypopnea index [AHI] of 24.7 ± 28.1/h in subjects with OSA and 3.0 ± 3.9/h in subjects without OSA, p < 0.001). The groups were matched for body mass index, with a mean body mass index of 40.3 ± 9.6 kg/m(2) in subjects with OSA and 38.9 ± 6.0 kg/m(2) in subjects without OSA (p = 0.48). A comparison of time spent with an oxygen saturation of less than 90% showed that subjects who had 1 minute or more of desaturation time per hour of sleep had lower GPIb fluorescence in circulating platelets, as compared with those subjects who had less than 1 minute of desaturation time per hour of sleep; similar findings were observed following 5 μM and 20 μM of ADP stimulation, as compared with control vehicle, suggesting higher levels of circulating platelet activity. In multivariate analyses, only nocturnal hypoxemia and female sex predicted agonist response. Platelet surface P-selectin, platelet surface-activated GPIIb/IIIa, PMA, and PNA were not significantly correlated with markers of OSA. In obese patients with OSA, platelet activation is associated with greater levels of oxygen desaturation, compared with matched control subjects. Metrics other than AHI (e.g., hypoxemia) may determine OSA-related thrombotic risk.

Positional therapy in ischemic stroke patients with obstructive sleep apnea

Background Obstructive sleep apnea (OSA) is common in stroke patients and is associated with poor functional outcome. The effects of positional therapy in ischemic stroke patients with OSA have not been investigated. We tested the hypothesis that ischemic stroke patients have less severe OSA during positional therapy that promotes nonsupine positioning. Methods We conducted a randomized, controlled, cross-over study. Sleep apnea screening studies were performed on two consecutive nights, using a portable respiratory monitoring system, on 18 subjects within the first 14 days of ischemic stroke. An apnea–hypopnea index (AHI) ⩾5 established the diagnosis of OSA. Subjects were randomized to positional therapy that included the use of a therapeutic pillow on either the first or second night. On the control night, subjects used the hospital pillow and were positioned ad lib. Treatment effect on AHI was estimated using a repeated measures model. Results All ischemic stroke subjects studied had OSA. The predominantly male group had a median age of 58 years, BMI of 29 kg/m 2, NIH Stroke Scale score of 3, and a median AHI on the nontherapeutic night of 39 (interquartile range: 21–54). Positional therapy reduced the amount of supine positioning by 36% (95% CI: 18–55% ( P < 0.001)). The AHI was reduced by 19.5% (95% CI: 4.9–31.9% ( P = 0.011)), when using positional therapy compared to sleeping ad lib. Conclusions Positional therapy to avoid supine positioning modestly reduces sleep apnea severity after ischemic stroke, and may therefore improve outcomes.

Improvement of sleep-related breathing disorder in patients with end-stage renal disease after kidney transplantation

Sleep-related breathing disorder (SRBD) is a common symptom of end-stage renal disease (ESRD). The aim of this study was to determine whether kidney transplantation improves SRBD. Twenty-four patients with ESRD, who were admitted for kidney transplantation, underwent a sleep study using a portable ventilation effort recorder on the night before transplantation. Of these patients, 20 could repeat the overnight monitoring two wk after the transplantation. The median apnea-hypopnea index (AHI) of the 20 patients was 13.5 (range, 2-40), and significantly reduced to 4.5 (range, 0-20) after transplantation (p = 0.003). This reduction was most prominent in 12 patients with SRBD, for whom the median AHI fell from 22 (range, 10-40) to 6.5 (range, 1-20; p = 0.010). SRBD improvement, defined as an AHI equal to or >50% and/or reduced to <10/h, was observed in eight of the 12 apneic patients. These results suggest that kidney transplantation may immediately improve SRBD in patients with ESRD. However, conclusions from this study should be taken with caution because of the limitations of our method, specifically the use of a portable recorder and a small number of patients.

Influence of gender on continuous positive airway pressure requirements in patients with obstructive sleep apnea syndrome

Gender differences have been noted in key aspects of upper airway physiology and pathophysiology of obstructive sleep apnea (OSA). We postulate that these will lead to disparities in pharyngeal collapsibility and, consequently, positive airway pressure requirements of patients with OSA. A retrospective review of 95 adult patients (56 women, 39 men) with OSA was done. Patients who underwent continuous positive airway pressure (CPAP) titration were included in the study. The study groups were similar with regard to the severity of OSA (median apnea-hypopnea index of 34 in men and 24 in women, p = 0.13). The men were older and less obese than the women (mean age of 46 and 41 years, p = 0.03, BMI of 42 and 49 kg/m(2), p < 0.001, in men and women, respectively); Epworth score was similar in the two groups (12 vs.11, p = 0.91). CPAP requirement was higher in men than in women (12.7 vs. 10.2, p < 0.0001). The effect of gender on CPAP requirement was found to be significant even when confounding variables were accounted for using linear regression. Men with OSA are more likely to require higher levels of CPAP support than women. The effect of gender on CPAP requirement persisted even after correcting for the severity of OSA.

Obstructive sleep disorders in Prader–Willi syndrome: The role of surgery and growth hormone

Objective To review the effectiveness and safety of surgical intervention for obstructive sleep apnea in Prader–Willi syndrome. Background The muscle hypotonia and obesity associated with Prader–Willi syndrome (PWS) result in a high rate of obstructive sleep apnea (OSA). The use of growth hormone therapy in these patients has been associated with sudden death, raising concerns that such treatment may exacerbate obstructive sleep apnea. As a result, it has been suggested that children with PWS be evaluated for OSA and indications for adenotonsillectomy prior to instituting growth hormone therapy. The true effectiveness of surgical intervention in these cases, however, remains in doubt. Methods Retrospective review of patients with a diagnosis of PWS who underwent adenoidectomy or adenotonsillectomy from January 2001 to July 2009 at a regional, tertiary care children's hospital. Patients underwent pre-operative and post-operative polysomnography. Differences between pre-operative and post-operative body-mass index (BMI), apnea-hypopnea index (AHI), and median oxygen saturation and oxygen saturation nadir were analyzed. Results Five patients were identified during the study period. Three patients underwent adenotonsillectomy, 1 patient adenoidectomy alone, and another adenotonsillectomy with uvulopalatopharyngoplasty (UPPP). While median AHI was found to have decreased from 16.4 to 4.4, no statistically significant change could be demonstrated ( p = 0.274). Mean O 2 and nadir O 2 saturation also improved, but without reaching statistical significance. No intra-operative complications were noted. Conclusions Our series, and other small case series, have demonstrated that complete resolution of sleep apnea in PWS patients is difficult to obtain with upper airway surgery alone. It is suggested that children with PWS being considered for growth hormone therapy undergo assessment for OSA by polysomnography. Patients identified with OSA should be referred for management by tonsillectomy and/or continuous positive airway pressure (CPAP) and then reassessed for residual airway obstruction prior to instituting hormonal therapy.

Sleep apnea syndrome in a young cosmopolite urban adult population: risk factors for disease severity

The purpose of this study is to investigate the risk factors for obstructive sleep apnea (OSA) in young patients from an urban European city with many migrants. The medical data of 2,343 patients referred for polysomnography from January 2007 till September 2009 were retrospectively reviewed in order to identify patients younger than 40 years with OSA and assess their characteristics. One hundred twenty-one of the 2,093 patients (6%) referred for diagnostic polysomnography were younger than 40 years and had OSA. There were 17 women and 104 men. The race was Caucasian in 55% (67/121) and African in 42% (51/121). The median apnea-hypopnea index (AHI) was 39 in men and 23 in women (p < 0.01), 30 in Caucasians and 39 in Africans (p = 0.03). BMI was positively correlated to the AHI (correlation of 0.19, p = 0.04). Multiple regression modeling showed that African origin (p = 0.01), current smoking (p = 0.05), and neck circumference (p < 0.01) were predictors of AHI, independently of BMI, but not the presence of upper airway abnormalities (p = 0.75). Co-morbidities were frequent (hypertension, 20%; diabetes, 13%; hypercholesterolemia, 27%; depression, 13%; reflux and gastric ulcer, 13%; hypothyroidism, 5%; asthma, 9%), and were related to BMI (p = 0.02), nocturnal desaturation time (p = 0.02), and African origin (p = 0.024). In patients aged <40 years and suffering from OSA, disease severity was associated with high BMI, large neck circumference, male sex, and African origin. After adjustment for BMI, African origin, tobacco use, and neck circumference remained predictors of high AHI. Neither upper airway abnormalities nor co-morbidities were found to be a risk factor for higher AHI in this group of young patients from a European city.

Exacerbation of sleep apnoea by frequent central events in patients with the obstructive sleep apnoea syndrome at altitude: a randomised trial

BackgroundMany patients with the obstructive sleep apnoea syndrome (OSA) travel to the mountains for recreational and professional activities while temporarily discontinuing continuous positive airway pressure (CPAP) treatment. A study was...