Change In Apnea-hypopnea Index Research Articles

Effect of continuous positive airway pressure in hypertensive patients with obstructive sleep apnea and high urinary metanephrines.

Some cases of pseudopheochromocytoma have been described among hypertensive patients with obstructive sleep apnea (OSA). This study examined whether a pathological rise of urinary metanephrines is a common feature in hypertensive OSA patients and, in such a case, whether the ventilation treatment during sleep (continuous or biphasic positive airway pressure) may normalize high metanephrines levels. Patients with endocrine diseases, drug abuse, therapy with TCA and cardiovascular events in the previous 6 months were excluded. Thirty-four hypertensive patients with OSA (BMI 40.6 ± 8.7 kg/m(2)) performed three 24-h urine collections for metanephrine assessment, before and after 1 month of ventilation therapy. Urinary normetanephrine (uNMT) was above the normal limit in 21 of 34 of the patients. In the 16 to 21 patients with high uNMT who were compliant to ventilation treatment, uNMT decreased in 13 by 26% and normalized in six of 13. uNMT levels were associated with apnea hypopnea index (AHI) (r = 0.799, P < 0.0001) and minimal SaO2 (r = -0.700, P < 0.01). The ventilation therapy-induced changes in AHI were associated with those in uNMT (r = 0.689, P < 0.005). In the multivariate analysis with uNMT changes as dependent variable and changes in AHI, BMI, SBP as independent variables, only AHI changes were independently associated with uNMT changes (β = 0.738, P < 0.01). Two-thirds of OSA hypertensive patients have uNMT values above the normal limit. The early identification of these patients is important as ventilation therapy can correct the pathological sympathoadrenal activation. Patients who do not normalize uNMT with ventilation therapy deserve a strict follow-up as this lack of normalization may indicate insufficient ventilation therapy or resistance of sympathetic hyperactivity to this treatment, not excluding an early stage of a chromaffin tumor.

Effect of Weight and Obstructive Sleep Apnea Severity on Sleep Surgery Outcomes in Children with Down Syndrome

Objectives: To assess the effect of weight status and obstructive sleep apnea (OSA) severity on polysomnographic (PSG) outcomes following sleep surgery inclusive of adenotonsillectomy (AT) in children with Trisomy 21. Methods: A retrospective chart review was completed on thirty-six children ages 1-13 years with Trisomy 21 and OSA who underwent at a tertiary care academic hospital between 2005 to 2015 and had both preoperative and postoperative PSGs. Postoperative changes in apnea hypopnea index (AHI) and other PSG parameters, including percentage of various sleep stages, were compared between children who were normal weight, overweight and obese.Results: The mean preoperative AHIs for normal weight, overweight and obese children were 15.6, 12.2 and 15.0, respectively while the mean postoperative AHIs were 10.6, 9.4 and 10.2, respectively. Improvement in AHI was significant only among children with severe OSA (AHI >10), but not among children with mild (AHI 1.5 to 5) or moderate OSA (AHI 5 to 10), both with and without controlling for weight status (p=0.01, p=0.009). There were no significant differences in postoperative PSG parameters comparing obese vs. non-obese and overweight vs. normal weight children. Conclusion: Weight status does not appear to affect sleep surgery outcomes in children with Trisomy 21. This subset of children was found to have persistent OSA following sleep surgery regardless of weight. Other factors associated with Trisomy 21, such as macroglossia, glossoptosis and hypotonia, may play a greater role in the pathogenesis of OSA in this patient population. Only those children with severe OSA were found to have a significant improvement in AHI after sleep surgery, inclusive of AT.

Effect of desipramine on patients with breathing disorders in RETT syndrome.

ObjectiveRett Syndrome (RTT) is a severe neurodevelopmental condition with breathing disorders, affecting around one in 10,000 female births. Desipramine, a noradrenaline reuptake inhibitor, reduced the number of apneas in Mecp2‐deficient mice, a model of RTT. We planned a phase 2 trial to test its efficacy and its safety on breathing patterns in 36 girls with RTT.MethodsThe trial was a 6‐month, multicenter, randomized, double‐blind, placebo‐controlled study registered with ClinicalTrials.gov, number NCT00990691. Girls diagnosed according to clinical examination and confirmed by genotyping were randomly assigned in a 1:1:1 ratio to receive 2–3 mg/kg Desipramine per day (high Desipramine), 1–2 mg/kg Desipramine per day (low Desipramine), or a placebo. The primary outcome was the change of apnea hypopnea index (AHI), defined by the number of apnea and hypopnea events per hour, assessed at 6 months from baseline. Intention‐to‐treat analysis was applied.ResultsThe median change in AHI from baseline to 6 months was −31 (IQR: −37 to −11) for the high Desipramine, −17.5 (IQR: −31 to 13) for the low Desipramine, and −13 (IQR:−31 to 0) for the placebo group. We did not find any significant difference in these changes between the groups (P = 0.781). A significant inverse correlation between Desipramine plasma concentration and AHI (r = −0.44; P = 0.0002) was underlined.InterpretationThis first clinical trial of desipramine did not show clinical efficacy. Although required further studies, the significant correlation between Desipramine concentrations and improvement of AHI provided additional and relevant reasons to test the noradrenergic pathway in RTT.

The Effect of Dietary Nitrate on Nocturnal Sleep-Disordered Breathing and Arterial Oxygen Desaturation at High Altitude.

Patrician, Alexander, Harald Engan, David Lundsten, Ludger Grote, Helena Vigetun-Haughey, and Erika Schagatay. The effect of dietary nitrate on nocturnal sleep-disordered breathing and arterial oxygen desaturation at high altitude. High Alt Med Biol 19:21-27, 2018.-Sleep-disordered breathing and fluctuations in arterial oxygen saturation (SaO2) are common during sleep among lowlanders ascending to high altitude. Dietary nitrate (NO3-) supplementation has been shown to lower the O2 consumption in various conditions. Our objective was to investigate whether dietary NO3- could reduce sleep-disordered breathing and SaO2 desaturation during sleep at altitude. Cardiorespiratory responses during sleep were measured in 10 healthy lowlanders at 330 m and then again in the Himalayas at 3700-4900 m. Each subject received two 70 mL shots of either beetroot juice (BR; ∼5.0 mmol NO3- per shot) or placebo (PL: ∼0.003 mmol NO3- per shot) in a single-blinded, weighted order over two consecutive nights at altitude. At 2.5-4.5 hours into sleep at altitude, BR increased the SaO2 desaturation drop (4.2 [0.1]% with PL vs. 5.3 [0.4]% with BR; p = 0.024) and decreased the SaO2 desaturation duration (14.1 [0.9] seconds with PL to 11.1 [0.9] seconds with BR; p = 0.0.041). There was a reduction in breaths with flow limitation (p = 0.025), but no changes in Apnea-Hypopnea Index (AHI), mean and minimum SaO2. The study suggests BR supplementation does not improve AHI or oxygenation, but may increase fluctuations in arterial O2 saturation during sleep at altitude in native lowlanders.

Effect of strength training on sleep apnea severity in the elderly: study protocol for a randomized controlled trial

BackgroundObstructive sleep apnea (OSA) occurs due to sleep-induced upper airway muscle relaxation resulting in increased pharyngeal collapsibility. Clinical trials have shown a favorable effect of exercise training on OSA severity in middle-aged adults. Aging is characterized by motor-unit loss. Force training may affect the whole body muscle tone. We hypothesize that interventions increasing muscle strength might propagate to motor units at the abductor pharyngeal muscles, reducing collapsibility and, hence, sleep apnea severity in elderly patients with obstructive sleep apnea.Methods/designThis is a randomized clinical trial including patients between 65 and 80 years of age, with obstructive sleep apnea, and an apnea-hypopnea index (AHI) between 20 and 50 events/hour, diagnosed by out-of-center in-home type III polysomnography. Forty subjects will be included and randomly assigned to two equal sized groups. The participants allocated to the intervention group will attend two sessions per week of one-hour strength training for the legs, arms, chest, back, and abdomen and the controls will receive advice on lifestyle change. The primary outcome measure of the study will be the change in apnea-hypopnea index and the secondary outcomes will be the body composition, evaluated by anthropometric and bioelectrical impedance variables; maximum dynamic force, appraised by one-repetition maximum strength test; muscle quality and thickness by ultrasound; physical function assessed by sit-to-stand test, timed up and go test, handgrip strength test. The study duration will be 12 weeks. Intention-to-treat and per-protocol analyses will be performed.DiscussionThe high prevalence of obstructive sleep apnea in elderly people is a public health issue. OSA is a recognized cause of cardiovascular disease and reduces quality of life due to sleepiness and fatigue. Exercise is a low-cost intervention that could help to detain the trend towards age-dependent loss of pharyngeal motor units and progressive severity of obstructive sleep apnea. Home-based strength exercises may represent a more practical approach than aerobic exercise for elderly patients. If the results confirm our hypothesis, further research on the clinical application of our findings will be warranted.Trial registrationClinicalTrials.gov, NCT02742792. Registered on 1 April 2016.

Effect of Mitral Valve Surgery on Overnight Fluid Shift and Sleep Apnea in Patients With Moderate to Severe Mitral Valve Regurgitation and Preserved Ejection Fraction

SESSION TITLE: Sleep 2 SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Rostral fluid shift from the legs is strongly associated with sleep apnea (SA) in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) accompanied by pulmonary congestion and/or pharyngeal edema. It is also known that sleep apnea is common among patients for cardiac surgery. Recent report showed that rheumatic valvular heart disease patients with obstructive SA had an increased incidence of perioperative complications, however the etiologies are unknown. Since MR contributes to pulmonary congestion and often have fluid retention in their legs, overnight fluid shift from the legs to the lungs or peripharyngeal area may play important roles in the pathogenesis of SA in patients with MR. Therefore, elucidating the relationship between fluid shift, SA, and effect of mitral valve (MV) surgery in patients with MR may provide some solutions. Purpose of this study is to investigate whether relationship between overnight fluid shit and severity of SA exists, and whether MV surgery affects either severity of SA and/or fluid shift, in patients with moderate-to-severe MR and preserved LVEF. METHODS: Patients with moderate-to-severe MR and preserved LVEF performed overnight polysomnography before and after the MV surgery. At the same time, leg fluid volume (LFV) was measured by bio-electrical impedance device before and after polysomnography. Relationship between overnight changes (△) of LFV and severity of SA as assessed by apnea-hypopnea index (AHI) was analyzed. RESULTS: Among 20 patients (mean age; 67±11 years, mean LVEF; 66±11%) enrolled, significant inverse relationship between △LFV and the AHI in univariable analysis (r=-0.78; P<0.001) was observed. Even in the multivariable regression analysis including other correlates to the AHI which showed P<0.1 in the univariable analyses, such as 24-hour urine volume (r=-0.46; P=0.041), regurgitant volume by PISA (r=0.46; P=0.049), use of diuretics (r=0.47; P=0.035) and beta blockers (r=054; P=0.014), △LFV was the significant correlates to the AHI (r=-0.72; P<0.001). 17 patients among them have done polysomnography after the surgery. Although body weight significantly decreased from 59.4±13.5 to 58.9±13.0 kg (P=0.004) following MV surgery, the AHI and △LFV did not change (AHI, from 27.9±18.5 to 31.4±18.0; P=0.463 and △LFV, from -397±188 to -401±202 ml; P=0.723). However, there were significant correlation between change in the AHI and change in △LFV, even after adjustment of change in the body weight (r=-0.58; P=0.035). CONCLUSIONS: Significant independent relationship between overnight fluid shift and SA severity were found in patients with moderate-to-severe MR and preserved LVEF. Despite no changes in AHI and LFV following MV surgery, there was a significant correlation between change in the AHI and change in △LFV. CLINICAL IMPLICATIONS: These findings suggest that in patients with moderate-to-severe MR and preserved LVEF, overnight rostral fluid displacement from the legs contributes to the pathogenesis of SA. Further investigation may contribute to reveal mechanisms. DISCLOSURE: Takatoshi Kasai: Grant monies (from industry related sources): affiliated with a department endowed by Philips Respironics, ResMed, and Fukuda Denshi The following authors have nothing to disclose: Azusa Murata, Shoichiro Yatsu, Hiroki Matsumoto, Takao Kato, Shoko Suda, Masaru Hiki, Kan Kajimoto, Taira Yamamoto, Atsushi Amano No Product/Research Disclosure Information

0458 ANTHROPOMETRIC DIFFERENCES IN OSA ACROSS FOUR ETHNIC GROUPS IN OSA ACROSS FOUR ETHNIC GROUPS

Obstructive Sleep Apnea (OSA) is a common sleep disorder with similar prevalence in different ethnic populations. Obesity is a major risk factor for OSA; however, the impact of obesity on OSA severity may vary with ethnicity due to differential disease etiology. We hypothesized that the association between Apnea-Hypopnea Index (AHI) and anthropometric measures of obesity will vary in strength between four ethnicities. Anthropometry (BMI, neck circumference) and AHI data were collected by clinical sleep centers within the Sleep Apnea Global Interdisciplinary Consortium (SAGIC). Data from 2966 subjects on 5 continents were collected and divided into four ethnic groups: Caucasian, African-American, South American, and Asian. The relationship between AHI and anthropometry was examined within each ethnicity by Spearman’s rank correlation and between ethnic groups using beta coefficients and interaction tests. AHI correlated with BMI (p &lt 0.0001) in all ethnicities (Caucasian: r=0.37, N=1325; African-American: r=0.25, N=330; Asian: r=0.41, N=265; South-American: r=0.47, N=769). While increased BMI was related to increased AHI, ethnicity influenced the strength of association (p &lt 0.0001). Asians were most susceptible, with each unit increase in BMI reflecting an expected 2.7 [2.1–3.3] (β[95% CI]) events/hour AHI increase. Impact of BMI was similar for Caucasians (1.2 [1.1–1.4]) and South Americans (1.5 [1.3–1.7]) with African-Americans showing only 0.8 [0.4–1.1] events/hour AHI change per BMI unit increase. Asians also showed the largest increase in AHI (3.5 [2.8–4.2]) per unit increase of neck circumference compared to African-Americans (2.3 [1.3–3.4]), Caucasians (1.9[1.7–2.2]), and South Americans (2.0 [1.7–2.3]). Higher obesity relates to more severe OSA in the 4 ethnic groups studied, but ethnicity modifies the strength of this relationship. Asians had the strongest relationship between obesity and AHI, indicating weight gain in this population will contribute more to OSA severity than in other ethnicities. Overall obesity had less impact in African-Americans; fat deposition around the neck may be more relevant in this population. N/A.

Improvement in Obstructive Sleep Apnea With Weight Loss is Dependent on Body Position During Sleep.

Weight loss fails to resolve obstructive sleep apnea (OSA) in most patients; however, it is unknown as to whether weight loss differentially affects OSA in the supine compared with nonsupine sleeping positions. We aimed to determine if weight loss in obese patients with OSA results in a greater reduction in the nonsupine apnea/hypopnea index (AHI) compared with the supine AHI, thus converting participants into supine-predominant OSA. Post hoc analysis of data from a randomized controlled trial assessing the effect of weight loss (bariatric surgery vs. medical weight loss) on OSA in 60 participants with obesity (body mass index: >35 and <55) with recently diagnosed (<6 months) OSA and AHI of ≥ 20 events/hour. Patients were randomized to very low calorie diet with regular review (n = 30) or to laproscopic adjustable gastric banding (n = 30) with follow-up sleep study at 2 years. Eight of 37 (22%) patients demonstrated a normal nonsupine AHI (<5 events/hour) on follow-up compared to 0/37 (0%) patients at baseline (p = .003). These patients were younger (40.0 ± 9.6 years vs. 48.4 ± 6.5 years, p = .007) and lost significantly more weight (percentage weight change -23.0 [-21.0 to -31.6]% vs. -6.9 [1.9 to -17.4], p = .001). The percentage change in nonsupine AHI was greater than the percentage change in supine AHI (-54.0 [-15.4 to -87.9]% vs -33.1 [-1.8 to -69.1]%, p = .05). However, the change in absolute nonsupine AHI was not related to change in absolute supine AHI (p = .23). Following weight loss, a significant proportion (22%) of patients with obesity have normalization of the nonsupine AHI. For these patients, supine sleep avoidance may cure their OSA.

Does intentional weight loss improve daytime sleepiness? A systematic review and meta-analysis.

Obesity is associated with excessive daytime sleepiness, but its causality remains unclear. We aimed to assess the extent to which intentional weight loss affects daytime sleepiness. Electronic databases were searched through 24 October 2016. Studies involving overweight or obese adults, a weight loss intervention and repeated valid measures of daytime sleepiness were included in the review. Two independent reviewers extracted data on study characteristics, main outcome (change in daytime sleepiness score standardized by standard deviation of baseline sleepiness scores), potential mediators (e.g. amount of weight loss and change in apnoea-hypopnoea index) and other co-factors (e.g. baseline demographics). Forty-two studies were included in the review. Fifteen before-and-after studies on surgical weight loss interventions showed large improvements in daytime sleepiness, with a standardized effect size of -0.97 (95% confidence interval [CI] -1.21 to -0.72). Twenty-seven studies on non-surgical weight loss interventions showed small-to-moderate improvement in daytime sleepiness, with a standardized effect size of -0.40 (95%CI -0.52 to -0.27), with no difference between controlled and before-and-after studies. We found a nonlinear association between amount of weight loss and change in daytime sleepiness. This review suggests that weight loss interventions improve daytime sleepiness, with a clear dose-response relationship. This supports the previously hypothesized causal effect of obesity on daytime sleepiness. It is important to assess and manage daytime sleepiness in obese patients.

Modest Improvement of Untreated Severe Sleep-Disordered Breathing in the Middle-Aged and Elderly.

ObjectiveIt has been reported that untreated sleep-disordered breathing (SDB) deteriorates over time, however this remains contentious. The aim of the present study is to evaluate the clinical course of SDB in middle-aged and older SDB patients, and to identify how relevant factors contribute to the change in SDB severity.MethodsBaseline and follow-up polysomnographic data of 56 untreated SDB patients (mean age, 61.2±5.71) were obtained retrospectively and the mean interval was 62.4±22.0 months. Subgroup analysis was performed based on the baseline severity, and the factors associated with the course of SDB were analyzed.ResultsAt the baseline, 13 subjects were simple snorers, 15 had mild to moderate SDB, and 28 were severe SDB patients. While there was no significant change in apnea-hypopnea index (AHI) as a whole, subgroup analysis showed decrease of AHI in severe SDB patients (43.9±10.6 to 35.6±20.0, p=0.009). The change in supine time percent and baseline AHI were associated with the change in AHI (β=0.387, p=0.003; β=-0.272, p=0.037).ConclusionUntreated SDB did not deteriorate over time with modest improvement in severe SDB. A proportion of severe SDB patients might expect decrease in SDB severity irrespective of changes in sleep position or body weight.

Investigation of the link between fluid shift and airway collapsibility as a mechanism for obstructive sleep apnea in congestive heart failure.

The increased prevalence of obstructive sleep apnea (OSA) in congestive heart failure (CHF) may be associated with rostral fluid shift. We investigated the effect of overnight rostral fluid shift on pharyngeal collapsibility (Pcrit), pharyngeal caliber (APmean), and apnea‐hypopnea index (AHI) in CHF patients. Twenty‐three optimally treated systolic CHF patients were studied. Neck circumference was measured immediately prior to sleep in the evening and immediately after waking in the morning as a marker of rostral fluid shift. Pcrit was measured during sleep, early and late in the night. APmean was measured using acoustic reflection at the same times as neck circumference measurements. 15/23 CHF patients experienced an overnight increase in neck circumference; overall neck circumference significantly increased overnight (mean±SD, evening: 41.7 ± 3.2 cm; morning: 42.3 ± 3.1 cm; P = 0.03). Pcrit increased significantly overnight (early‐night: −3.8 ± 3.3 cmH2O; late‐night: −2.6 ± 3.0 cmH2O; P = 0.03) and APmean decreased (evening: 4.2 ± 1.3 cm2; morning: 3.7 ± 1.3 cm2; P = 0.006). The total AHI correlated with neck circumference (r = 0.4; P = 0.04) and Pcrit (r = 0.5; P = 0.01). APmean correlated with neck circumference (r = −0.47; P = 0.02). There was no significant change in AHI between the first and second half of the night (first‐half: 12.9 ± 12.4/h; second‐half: 13.7 ± 13.3/h; P = 0.6). Overnight rostral fluid shift was associated with increased pharyngeal collapsibility and decreased pharyngeal caliber during sleep in CHF patients. Rostral fluid shift may be an important mechanism of OSA in this patient group.

Risk of failure of adenotonsillectomy for obstructive sleep apnea in obese pediatric patients

IntroductionPediatric obesity is a leading risk factor for obstructive sleep apnea (OSA), a condition commonly treated with adenotonsillectomy (T&A). It has been hypothesized that obesity increases a child's risk of failing T&A for OSA, however this relationship has not yet been quantified. The primary objective of this study was to investigate the relationship between obesity as measured by perioperative Body Mass Index (BMI) and persistent OSA following T&A as measured by polysomnography (PSG). Study designRetrospective chart review. MethodsPediatric patients who underwent T&A between Jan. 2004 and Jan. 2016 were included. We recruited both obese and non-obese patients to compare caregiver/self reported improvement. Obese patients were recruited from a weight management clinic and included if they had a BMI z-score >1.65 and had pre- and post-operative polysomnograms (PSGs). Control patients included those undergoing T&A for OSA at our institution with BMI <1.65. These patients were age matched to the obese patient population. Age, gender, perioperative BMI z-score, caregiver/self reported improvement, total Apnea-Hypopnea Index (AHI), and O2 saturation nadir were collected where available. Univariate linear regressions were calculated between perioperative BMI z-score and PSG data. Results26 obese study and 47 control subjects were identified for analysis. T&A resulted in statistically significant improvements in total AHI (p = 0.030) and nadir O2 saturation (p = 0.013) in obese subjects. There was no significant difference between the rate of caregiver/self reported improvement in the two groups. There was a statistically significant correlation between perioperative BMI z-score and the change in total AHI (p = 0.049). Within our population, for every increase by 0.1 in perioperative BMI z-score, the improvement in total AHI post-operatively decreased by 1.63 events/hr. Further, patients with BMI more than 3 standard deviations away from the age-derived normative mean received essentially no benefit from T&A alone. ConclusionsOur study established an inverse linear relationship between perioperative BMI z-score and improvement in total AHI with essentially no improvement in patients with BMI z-scores >3. Further studies are required to further elucidate this relationship and investigate the role of additional procedures in the initial management of OSA in obese children.

Comparison of treatment outcomes between intracapsular and total tonsillectomy for pediatric obstructive sleep apnea

BackgroundIntracapsular tonsillectomy (IT) has been advocated as a treatment for pediatric obstructive sleep apnea (OSA). However, evidence in the literature utilizing polysomnography (PSG) is limited. ObjectiveTo examine the experience at a tertiary children's hospital to evaluate the effectiveness and risks of intracapsular tonsillectomy compared to total tonsillectomy (TT) for treating pediatric OSA. MethodsA retrospective study was undertaken of pediatric tonsillectomy cases performed for OSA at a tertiary children's hospital from 2005 to 2010. Patients with recurrent tonsillitis, craniofacial abnormalities, chromosomal abnormalities, neuromuscular disease, and congenital malformations were excluded. Main outcome measures were apnea-hypopnea index (AHI), minimum oxygen saturation (minO2), and surgical complications. ResultsOf the 1583 patients reviewed in this study, there were 75 IT and 93 TT patients with pre- and post-operative PSG results. The IT patients were younger, had lower BMI, larger tonsil size, lower pre-operative (AHI) and lower post-operative AHI (p < 0.05). There was a similar percentage of patients that showed improvement in AHI and minimum oxygen saturation between the IT and TT groups. There were statistically similar average change in AHI and minimum oxygen saturation between the IT and TT groups at 5.6 ± 8.6 and 8.6 ± 12.9, respectively (p = 0.8) as well as similar improvement in minimum oxygen saturation between the two groups at 3.3% ± 4.3% and 3.0% ± 5.2%, respectively (p = 0.66). Of TT patients, 2.9% experienced post-operative bleeding with 1.6% requiring OR for control of hemorrhage. Of IT patients, 2.2% were found to have tonsillar regrowth with 2.0% returning to the OR for secondary tonsillectomy. ConclusionsIntracapsular tonsillectomy, like total tonsillectomy, is effective in improving polysomnogram results in appropriately selected children. Intracapsular tonsillectomy is a suitable option for the surgical treatment of pediatric OSA consequent to its demonstrated efficacy in relieving OSA and its favorable safety profile.

Association of sleep time in supine position with apnea-hypopnea index as evidenced by successive polysomnography

The purpose of this study is to evaluate the impact of body position during sleep on apnea-hypopnea index (AHI) and night-to-night variability in polysomnography (PSG) parameters. Totally, 30 patients with obstructive sleep apnea syndrome (OSAS) were assessed prospectively with successive PSGs performed. The patients were categorized as increased (group A), decreased (group B), and unchanged (group C) AHI between the first and second PSG evaluations performed at least 1-week interval. The mean AHI values were significantly higher in the second night (p=0.02). A change in AHI was found in almost 85% of the patients between two successive measurements. According to multivariate and correlation analyses and differences in total AHI in supine position (r=0.897), it was found that the influence of the supine position was the primary factor contributing to the night-to-night variability. Supine AHI, non-supine AHI, and non-supine time findings did not add any significance on total AHI. The variability observed in the AHI seems related to amount of sleeping time spent in supine position, suggesting that mean AHI alone is not that reliable in the accurate diagnosis of OSAS severity. A thorough evaluation of AHI in supine and non-supine positions is needed in order to understand better the severity of OSAS.

Positional therapy in patients with residual positional obstructive sleep apnea after upper airway surgery

A considerable portion of patients has residual positional obstructive sleep apnea (POSA) after upper airway surgery. Those patients could benefit from additional treatment with positional therapy (PT). The objective of this prospective study was to assess the additional effect of PT in patients with residual POSA after upper airway surgery for sleep apnea. A polysomnography (PSG) was used to diagnose a patient with residual POSA after surgery. After informed consent, patients were treated with PT for 3months and underwent a follow-up PSG while using the sleep position trainer (SPT). Changes in apnea-hypopnea index (AHI) and sleep position parameters were analyzed. Compliance rates and mean disease alleviation (MDA) were determined. Thirty-three patients with a median postoperative AHI of 18.3/h sleep were included. With the SPT median AHI dropped to 12.5/h sleep and the Epworth Sleepiness Scale (ESS) improved from 10.0 to 7.0. After 3months, 37.5% patients were considered responders of whom 31.3% had treatment success. The compliance rate with SPT was 89.0%. MDA was 44.7% for SPT alone. With the combination of both surgery and SPT, MDA was 65.6%. The results of this study indicate that additional PT in a complex OSA patient population with residual POSA after surgery can increase overall therapeutic effectiveness by improving the median MDA from 39.5% (effect of surgery alone) to 65.6% (effect of combining surgery and PT).

Effect of liraglutide 3.0 mg in individuals with obesity and moderate or severe obstructive sleep apnea: the SCALE Sleep Apnea randomized clinical trial.

Background:Obesity is strongly associated with prevalence of obstructive sleep apnea (OSA), and weight loss has been shown to reduce disease severity.Objective:To investigate whether liraglutide 3.0 mg reduces OSA severity compared with placebo using the primary end point of change in apnea–hypopnea index (AHI) after 32 weeks. Liraglutide's weight loss efficacy was also examined.Subjects/Methods:In this randomized, double-blind trial, non-diabetic participants with obesity who had moderate (AHI 15–29.9 events h−1) or severe (AHI ⩾30 events h−1) OSA and were unwilling/unable to use continuous positive airway pressure therapy were randomized for 32 weeks to liraglutide 3.0 mg (n=180) or placebo (n=179), both as adjunct to diet (500 kcal day−1 deficit) and exercise. Baseline characteristics were similar between groups (mean age 48.5 years, males 71.9%, AHI 49.2 events h−1, severe OSA 67.1%, body weight 117.6 kg, body mass index 39.1 kg m−2, prediabetes 63.2%, HbA1c 5.7%).Results:After 32 weeks, the mean reduction in AHI was greater with liraglutide than with placebo (−12.2 vs −6.1 events h−1, estimated treatment difference: −6.1 events h−1 (95% confidence interval (CI), −11.0 to −1.2), P=0.0150). Liraglutide produced greater mean percentage weight loss compared with placebo (−5.7% vs −1.6%, estimated treatment difference: −4.2% (95% CI, −5.2 to −3.1%), P<0.0001). A statistically significant association between the degree of weight loss and improvement in OSA end points (P<0.01, all) was demonstrated post hoc. Greater reductions in glycated hemoglobin (HbA1c) and systolic blood pressure (SBP) were seen with liraglutide versus placebo (both P<0.001). The safety profile of liraglutide 3.0 mg was similar to that seen with doses ⩽1.8 mg.Conclusions:As an adjunct to diet and exercise, liraglutide 3.0 mg was generally well tolerated and produced significantly greater reductions than placebo in AHI, body weight, SBP and HbA1c in participants with obesity and moderate/severe OSA. The results confirm that weight loss improves OSA-related parameters.

The Effect of Changes in Cardiorespiratory Fitness and Weight on Obstructive Sleep Apnea Severity in Overweight Adults with Type 2 Diabetes

To examine the effect of changes in cardiorespiratory fitness on obstructive sleep apnea (OSA) severity prior to and following adjustment for changes in weight over the course of a 4-y weight loss intervention. As secondary analyses of a randomized controlled trial, 263 overweight/obese adults with type 2 diabetes and OSA participated in an intensive lifestyle intervention or education control condition. Measures of OSA severity, cardiorespiratory fitness, and body weight were obtained at baseline, year 1, and year 4. Change in the apnea-hypopnea index (AHI) served as the primary outcome. The percentage change in fitness (submaximal metabolic equivalents [METs]) and change in weight (kg) were the primary independent variables. Primary analyses collapsed intervention conditions with statistical adjustment for treatment group and baseline METs, weight, and AHI among other relevant covariates. At baseline, greater METs were associated with lower AHI (B [SE] = -1.48 [0.71], P = 0.038), but this relationship no longer existed (B [SE] = -0.24 [0.73], P = 0.75) after adjustment for weight (B [SE] = 0.31 [0.07], P < 0.0001). Fitness significantly increased at year 1 (+16.53 ± 28.71% relative to baseline), but returned to near-baseline levels by year 4 (+1.81 ± 24.48%). In mixed-model analyses of AHI change over time without consideration of weight change, increased fitness at year 1 (B [SE] = -0.15 [0.04], P < 0.0001), but not at year 4 (B [SE] = 0.04 [0.05], P = 0.48), was associated with AHI reduction. However, with weight change in the model, greater weight loss was associated with AHI reduction at years 1 and 4 (B [SE] = 0.81 [0.16] and 0.60 [0.16], both P < 0.0001), rendering the association between fitness and AHI change at year 1 nonsignificant (B [SE] = -0.04 [0.04], P = 0.31). Among overweight/obese adults with type 2 diabetes, fitness change did not influence OSA severity change when weight change was taken into account. ClinicalTrials.gov identification number NCT00194259.

Current Concepts in Assessing Outcomes for OSA Surgery

The typical patient with obstructive sleep apnea (OSA) suffers from frequent nocturnal hypoxemia, sympathetic overdrive, tachycardia, nocturnal hypertension, oxidative metabolic stress, and unrefreshed sleep. These patients subsequently have daytime somnolence, poor memory, irritability, poor concentration, low work productivity, hypertension, mood swings, and even depression. These affect the OSA patient’s entire quality of life (QOL) and mental state. The gold standard diagnostic test for OSA is overwhelmingly cited as the overnight polysomnography (PSG). During the overnight polysomnogram, the frequency of obstructive events is reported as the apnea-hypopnea index (AHI); the severity of the OSA is deemed and based on the number of apnea and hypopnea events per hour. As consequence the effectiveness of each and/or combined surgical interventions for OSA is almost exclusively based on the reported changes in AHI post-operatively, again, from the polysomnogram; moreover, based on a specific arbitrarily assigned reduction in AHI (50 % reduction) and an AHI below 15 commonly known as the Sher criteria. However, recent evidence has shown that there is a consistent discordance between the levels of AHI used to denote outcomes/success of therapy and real-world clinical outcomes such as QOL, patient perception of disease, cardiovascular measures, and/or survival. Moreover, in many areas of medicine patient-reported outcome measures (PROM) and QOL assessments are gaining substantial traction as priority items to assess when gauging effect of therapy for all manner of diseases, yet in the case of OSA the AHI remains paradoxically persistent as the main, and frequently the only, outcome measure reported in the vast majority of surgical and non-surgical OSA studies in the literature. How success at therapy is measured when treating OSA needs re-evaluation in light of this evidence, and we propose SLEEP GOAL as a more appropriate means of doing so.

Nasal Dilators (Breathe Right Strips and NoZovent) for Snoring and OSA: A Systematic Review and Meta-Analysis.

Objective. To systematically review the international literature for studies evaluating internal (NoZovent) and external (Breathe Right Strips) nasal dilators as treatment for obstructive sleep apnea (OSA). Study Design. Systematic review with meta-analysis. Methods. Four databases, including PubMed/MEDLINE, were searched through September 29, 2016. Results. One-hundred twelve studies were screened, fifty-eight studies were reviewed, and fourteen studies met criteria. In 147 patients, the apnea-hypopnea index (AHI) was reported, and there was an improvement from a mean ± standard deviation (M ± SD) of 28.7 ± 24.0 to 27.4 ± 23.3 events/hr, p value 0.64. There was no significant change in AHI, lowest oxygen saturation, or snoring index in OSA patients when using nasal dilators. However, a subanalysis demonstrated a slight reduction in apnea index (AI) with internal nasal dilators (decrease by 4.87 events/hr) versus minimal change for external nasal dilators (increase by 0.64 events/hr). Conclusion. Although nasal dilators have demonstrated improved nasal breathing, they have not shown improvement in obstructive sleep apnea outcomes, with the exception of mild improvement in apnea index when internal nasal dilators were used.

Relationship between Clinical and Polysomnography Measures Corrected for CPAP Use.

The changes in patient-reported measures of obstructive sleep apnea (OSA) burden are largely discordant with the change in apnea-hypopnea index (AHI) and other polysomnography measures before and after treatment. For patients treated with continuous positive airway pressure (CPAP), some investigators have theorized that this discordance is due in part to the variability in CPAP use. We aim to test the hypothesis that patient-reported outcomes of CPAP treatment have stronger correlations with AHI when it is corrected for mean nightly CPAP use. This was a cross-sectional study of 459 adults treated with CPAP for OSA. Five patient-reported measures of OSA burden were collected at baseline and after 6 months of CPAP therapy. The correlations between the change in each patient-reported measure and the change in AHI as well as mean nightly AHI (corrected for CPAP use with a weighted average formula) were measured after 6 months of treatment. The same analysis was repeated for 4 additional polysomnography measures, including apnea index, arousal index, lowest oxyhemoglobin saturation, and desaturation index. The change in AHI was weakly but significantly correlated with change in 2 of the 5 clinical measures. The change in mean nightly AHI demonstrated statistically significant correlations with 4 out of 5 clinical measures, though each with coefficients less than 0.3. Similar results were seen for apnea index, arousal index, lowest oxyhemoglobin saturation, and desaturation index. Correction for CPAP use yielded overall small but significant improvements in the correlations between patient-reported measures of sleep apnea burden and polysomnography measures after 6 months of treatment.