Sleep architecture following a weight loss intervention in overweight and obese patients with obstructive sleep apnea and type 2 diabetes: relationship to apnea-hypopnea index

The Effect of Type-2 Diabetes Mellitus on Sleep Architecture and Sleep Apnea Severity in Patients With Obstructive Sleep Apnea Syndrome

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is a severe condition that is characterized by recurrent partial or complete breathing interruptions during sleep, leading to insulin resistance, microvascular complications, and cardiovascular complications. It is of great importance to know the impact of type 2 diabetes mellitus (DM), which is prevalent in the world and in our country, Turkey, leads to significant mortality and morbidity, significantly affects the quality of life, and requires continuous follow-up, on sleep in patients with OSAS and to raise awareness on this issue. In this study, we aimed to determine the effects of diabetes on sleep duration and sleep architecture in patients with OSAS and to investigate the relationship between OSAS severity and DM control.

METHODS

Fifty diabetic and 42 non-diabetic patients diagnosed with OSAS at the Sleep Disorders Center of Süreyyapaşa Chest Diseases and Thoracic Surgery Training and Research Hospital, Istanbul, Turkey, between October 2022 and March 2023 were included in the study. Polysomnographic and biochemical parameters of the two groups were compared. The effect of OSAS severity and sleep architecture on diabetes control was investigated.

RESULTS

No significant difference was found between diabetic and non-diabetic patients in terms of total sleep duration, sleep efficiency, and sleep latency, whereas REM (rapid eye movement) latency was prolonged and REM sleep duration and percentage were significantly lower in diabetic patients. The severity of OSAS was found to be greater in diabetic patients and they spent significantly more time below 90% saturation during sleep. No correlation was found between the groups in the glycated hemoglobin (HbA1c) parameter, which we examined in terms of diabetes control, sleep architecture, and OSAS severity.

CONCLUSION

The presence of diabetes aggravates the severity of OSAS, prolongs the transition to REM sleep, and leads to a decrease in REM duration. Sleep is essential for both mental and physical well-being. In this regard, it is of utmost importance to examine diabetic patients for OSAS and to perform polysomnography in appropriate patients.

Rapid eye movement sleep loss associated cytomorphometric changes and neurodegeneration

Rapid eye movement sleep (REMS) is essential for leading normal healthy living at least in higher-order mammals, including humans. In this review, we briefly survey the available literature for evidence linking cytomorphometric changes in the brain due to loss of REMS. As a mechanism of action, we add evidence that REMS loss elevates noradrenaline (NA) levels in the brain, which affects neuronal cytomorphology. These changes may be a compensatory mechanism as the changes return to normal after the subjects recover from the loss of REMS or if during REMS deprivation, the subjects are treated with NA-adrenoceptor antagonist prazosin (PRZ). We had proposed earlier that one of the fundamental functions of REMS is to maintain the level of NA in the brain. We elaborate on this idea to propose that if REMS loss continues without recovery, the sustained level of NA breaks down neurophysiologically active compensatory mechanism/s starting with changes in the neuronal cytomorphology, followed by their degeneration, leading to acute and chronic pathological conditions. Identification of neuronal cytomorphological changes could prove to be of significance for predicting future neuronal (brain) damage as well as an indicator for REMS health. Although current brain imaging techniques may not enable us to visualize changes in neuronal cytomorphology, given the rapid technological progress including use of artificial intelligence, we are optimistic that it may be a reality soon. Finally, we propose that maintenance of optimum REMS must be considered a criterion for leading a healthy life.

Increased plasma ANGPTL7 levels with increased obstructive sleep apnea severity

BACKGROUND

Weight-loss surgery is one of the recommended methods for treating obstructive sleep apnea (OSA) in obese patients. While weight reduction is critical to relieve symptoms of OSA, the biochemical factors involved in post-surgery improvement are still unknown. We aimed to explore the link between ANGPTL7 and OSA in patients with different OSA severity. Furthermore, we examined the effect of treating OSA with bariatric surgery on ANGPTL7 level.

METHODS

We quantified levels of circulating ANGPTL7 in fasting plasma and adipose tissue samples of 88 participants before and after bariatric surgery. Confocal microscopy analyses were also performed to assess the ANGPTL7 expression in subcutaneous white adipose tissue biopsies obtained from people with moderate-to-severe OSA compared to those with none or mild OSA. The study involved 57 individuals with none or mild OSA and 31 patients with moderate-to-severe OSA.

RESULTS

Levels of circulating ANGPTL7 were significantly higher in people with moderate-to-severe OSA (1440 ± 1310 pg/ml) compared to the none or mild OSA group (734 ± 904 pg/ml, p = 0.01). The increase in ANGPTL7 correlated significantly and positively with the apnea-hypopnea index (AHI, r = .226, p = .037), and AHI-supine (r = .266, p = .019) in participants with moderate-to-severe OSA. Multivariate logistic regression analysis demonstrated an association between ANGPTL7 and OSA severity (log₂ ANGPTL7; OR =1.24, p = 0.024). ANGPTL7 levels exhibited significant positive correlations with the levels of TG and oxLDL (p-value = 0.002 and 0.01 respectively). Bariatric surgery reduced the levels of both ANGPTL7 and AHI significantly.

CONCLUSION

Here we report significantly increased levels of ANGPTL7 both in the circulation and in adipose tissue of patients with OSA, which concurred with increased inflammation and OSA severity. Levels of ANGPTL7 decreased significantly as OSA showed a significant improvement post-surgery supporting a potential role for ANGPTL7 in either OSA progression or a role in an OSA-related mechanism.

The Rise of IGFBP4 in People with Obstructive Sleep Apnea and Multilevel Sleep Surgery Recovers Its Basal Levels

IGFBP4 is the smallest member of the insulin-like growth factor binding protein family (IGFBP). It is a hepatic protein that plays a role in modulating the activity and bioavailability of IGF-I. The expression of IGFBP4 was found to increase under conditions of hypoxia. Obstructive sleep apnea (OSA) is a common disorder, characterized by cyclic episodes of intermittent hypoxia and fragmented sleep. Our aim was to quantify levels of circulating IGFBP1, IGFBP2, IGFBP3, IGFBP4, and IGFBP7 in fasting plasma samples of 69 Kuwaiti participants and explore its correlation with indices of OSA. The quantification was performed using multiplexing assay. The study involved 28 controls and 41 patients with OSA. Levels of circulating IGFBP4 were significantly higher in people with OSA (289.74 ± 23.30 ng/ml) compared to the control group (217.60 ± 21.74 ng/ml, p = 0.028). The increase in IGFBP4 correlated significantly and positively with AHI (r = .574, p = .01) and AI (r = .794, p = .001) in people with moderate and severe OSA. There was a significant decline in circulating IGFBP4 after 3 months of surgery (225.89 ± 18.16 ng/ml, p = 0.012). This was accompanied by a prominent improvement in OSA (AHI 8.97 ± 2.37 events/h, p = 0.001). In this study, our data showed a significant increase in circulating IGFBP4 in people with OSA. We also report a significant positive correlation between IGFBP4 and indices of OSA at baseline, which suggests IGFBP4 as a potential diagnostic biomarker for OSA. There was a significant improvement in OSA after 3 months of surgical intervention, which concurred with a significant decline in IGFBP4 levels. Altogether, the detected change suggests a potential link between IGFBP4 and OSA or an OSA-related factor, whereby OSA might play a role in triggering the induction of IGFBP4 expression.

Predictors of weight loss in obese patients with obstructive sleep apnea

PURPOSE

Consistent predictors of weight loss outcomes with very low-energy diets (VLEDs) in obstructive sleep apnea (OSA) have not been identified. This study aimed to identify variables predictive of weight loss success in obese patients with OSA undertaking an intensive weight loss programme.

METHODS

We analysed biological, psychological, and behavioural variables as potential predictors of weight loss in obese patients with OSA after a 2-month VLED followed by one of two 10-month weight loss maintenance diets. Actigraphy, in-lab polysomnography, urinary catecholamines, and various psychological and behavioural variables were measured at baseline, 2, and 12 months. Spearman's correlations analysed baseline variables with 2-month weight loss, and 2-month variables with 2-12 month-weight change.

RESULTS

Forty-two patients completed the VLED and thirty-eight completed the maintenance diets. Actigraphy data revealed that late bedtime (r_s =  - 0.45, p =  < 0.01) was correlated with 2-month weight loss. The change in the time that participants got out of bed (rise-time) from baseline to two months was also correlated with 2-month weight loss (r_s = 0.36, p = 0.03). The Impact of Weight on Quality of Life-Lite questionnaire (IWQOL) Public Distress domain (r_s =  - 0.54, p =  < 0.01) and total (r_s =  - 0.38, p = 0.02) scores were correlated with weight loss maintenance from 2 to 12 months.

CONCLUSIONS

Results from this small patient sample reveal correlations between actigraphy characteristics and weight loss in obese patients with OSA. We suggest the IWQOL may also be a useful clinical tool to identify OSA patients at risk of weight regain after initial weight loss.

CLINICAL TRIAL REGISTRATION

This clinical trial was prospectively registered on 18/02/2013 with the Australia and New Zealand Clinical Trials Registry (ACTRN12613000191796).

PUBLIC REGISTRY TITLE

Sleep, Lifestyle, Energy, Eating, Exercise Program for the management of sleep apnea patients indicated for weight loss treatment: A randomised, controlled pilot study. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363680.

Use of polysomnography and home sleep apnea tests for the longitudinal management of obstructive sleep apnea in adults: an American Academy of Sleep Medicine clinical guidance statement

INTRODUCTION

Obstructive sleep apnea is an important and common disorder with associated health risks. Assuring successful longitudinal management is vital to patient health and sleep-related quality of life. This paper provides guidance from the American Academy of Sleep Medicine (AASM) regarding the use of polysomnography (PSG) and home sleep apnea tests (HSATs) after a diagnosis of obstructive sleep apnea has been established and, in most cases, treatment implemented.

METHODS

The AASM commissioned a task force of five sleep medicine experts. A literature search was conducted to identify studies that included adult patients with OSA who underwent follow-up PSG or an HSAT. The task force developed clinical guidance statements based on a review of these studies and expert opinion. The AASM Board of Directors approved the final clinical guidance statements.

CLINICAL GUIDANCE STATEMENTS

The AASM supports the following clinical guidance statements on indications for follow-up PSG and HSAT in adult patients with OSA. 1. Follow-up PSG or HSAT is not recommended for routine reassessment of asymptomatic patients with obstructive sleep apnea on PAP therapy, however, follow-up PSG or HSAT can be used to reassess patients with recurrent or persistent symptoms, despite good PAP adherence. 2. Follow-up PSG or HSAT is recommended to assess response to treatment with non-PAP interventions. 3. Follow-up PSG or HSAT may be used if clinically significant weight gain or loss has occurred since diagnosis of OSA or initiation of its treatment. 4. Follow-up PSG may be used for reassessment of sleep-related hypoxemia and/or sleep-related hypoventilation following initiation of treatment for OSA. 5. Follow-up PSG or HSAT may be used in patients being treated for OSA who develop or have a change in cardiovascular disease. 6. Follow-up PSG may be used in patients with unexplained PAP device-generated data. The ultimate judgment regarding propriety of any specific care must be made by the clinician, in light of the individual circumstances presented by the patient, available diagnostic tools, accessible treatment options and resources.

Impact of weight loss interventions on patient-reported outcomes in overweight and obese adults with type 2 diabetes: a systematic review

Previous reviews explored weight loss-induced metabolic changes in overweight and obese adults with type 2 diabetes (T2D) but did not report on the impact on patient-reported outcomes (PROs). This systematic review investigated the effect of weight loss interventions on weight loss and PROs in overweight and obese adults with T2D. We searched three electronic databases from inception to March 2018 for randomised controlled trials (RCTs) of weight loss interventions in overweight and obese (according to BMI) adults aged ≥ 18 years reporting changes in PROs from baseline to at least one follow-up assessment during or post-intervention. One reviewer screened abstracts, performed data extraction, and conducted the narrative synthesis, with 25% cross-checking by a second reviewer. We extracted data relating to sample characteristics, intervention and comparison conditions, weight loss, and change in PROs. We identified 540 papers of which 23 met eligibility reporting on 19 RCTs. Four types of interventions (diet, surgery, pharmacological, and multi-component lifestyle interventions) significantly reduced weight. Weight loss was consistently associated with improvements in sexual and physical function across all intervention types, with diet and multi-component lifestyle interventions producing more substantial improvements than surgical or pharmacological interventions. Findings for other PROs, such as HRQOL and depressive symptoms, were inconsistent across studies and intervention types. The four weight loss interventions can be prescribed to engender weight loss in overweight and obese adults with T2D, with multi-component lifestyle interventions generating substantial improvements in physical and sexual function, perhaps due to the potency of exercise in improving PROs.

The validity of two commercially-available sleep trackers and actigraphy for assessment of sleep parameters in obstructive sleep apnea patients

Objective

The use of activity and sleep trackers that operate through dedicated smartphone applications has become popular in the general population. However, the validity of the data they provide has been disappointing and only Total Sleep Time (TST) is reliably recorded in healthy individuals for any of the devices tested. The purpose of this study was to evaluate the ability of two sleep trackers (Withings pulse 02 (W) and Jawbone Up (U)) to measure sleep parameters in patients suffering from obstructive sleep apnea (OSA).

Methods

All patients evaluated for OSA in our sleep laboratory underwent overnight polysomnography (PSG). PSG was conducted simultaneously with three other devices: two consumer-level sleep monitors (U and W) and one actigraph (Bodymedia SenseWear Pro Armband (SWA)).

Results

Of 36 patients evaluated, 22 (17 men) were diagnosed with OSA (mean apnea-hypopnea index of 37+ 23/h). Single comparisons of sleep trackers (U and W) and actigraph (SWA) were performed. Compared to PSG, SWA correctly assessed TST and Wake After Sleep Onset (WASO), and U and W correctly assessed Time In Bed (TIB) and light sleep. Intraclass correlations (ICC) revealed poor validity for all parameters and devices, except for WASO assessed by SWA.

Conclusions

This is the first study assessing the validity of sleep trackers in OSA patients. In this series, we have confirmed the limited performance of wearable sleep monitors that has been previously observed in healthy subjects. In OSA patients, wearable app-based health technologies provide a good estimation of TIB and light sleep but with very poor ICC.

Sleep fragmentation delays wound healing in a mouse model of type 2 diabetes

Study Objectives

This study tested the hypothesis that sleep fragmentation (SF) delays wound healing in obese B6.BKS(D)-Leprdb/J (db/db) mice with impaired leptin signaling and type 2 diabetes compared with wild-type C57BL/6J (B6) mice.

Methods

Adult male mice (n = 34) were anesthetized and bilateral full-thickness excisional wounds were created on the back of each mouse. Half of the db/db and B6 mice were housed in SF cages equipped with a bar that moved across the cage floor every 2 min, 12 hr/day for 23 days. The other half of each group of mice was housed in the same room and did not experience SF. The dependent measures were number of days required to achieve wound closure, mRNA expression of four inflammatory mediators, blood glucose, insulin, and corticosterone.

Results

SF in the db/db mice caused a significant delay in wound healing relative to db/db mice with no SF. Days to achieve 50 per cent wound healing were 13.3 ± 0.4 with SF compared with 10.3 ± 0.7 without SF. All B6 mice achieved 50 per cent wound healing within 6 days and complete healing after 16 days. SF caused a significant increase in wound levels of TNF-α mRNA only in the db/db mice and an increase in corticosterone only in the B6 mice.

Conclusions

The delayed wound healing in obese, diabetic mice caused by SF is homologous to delayed wound healing in some patients with type 2 diabetes. The results support the interpretation that altered leptinergic signaling and inflammatory proteins contribute to delayed wound healing.

Weight loss surgery for obstructive sleep apnoea with obesity in adults: a systematic review and meta-analysis protocol

INTRODUCTION

Obstructive sleep apnoea (OSA) is caused by complete or partial obstruction of the upper airway resulting in repeated episodes of interrupted or shallow breaths. OSA is associated with significant morbidity and mortality. The prevalence is estimated to range from 3% to 7% in the general population but may be much higher. Several studies show that weight loss or bariatric surgery may have a role in treating OSA. The aim of this systematic review is to assess the safety and efficacy of randomised controlled trials (RCTs) of weight loss surgery for adults with OSA and comorbid obesity.

METHODS AND ANALYSIS

A search of the Cochrane Central Register of Controlled Trials, PubMed, EMBASE and two major Chinese biomedical databases will be performed to identify related trials published as of October 2018. This study will include RCTs, comparing different types of weight loss surgery for OSA with obesity or weight loss surgery for OSA with obesity with other upper airway surgeries. The primary outcomes that will be measured are apnoea-hypopnoea index, excess weight loss and in-hospital mortality. The secondary outcomes will include duration of hospital stay, neck circumference, reoperation, waist circumference, body mass index, Epworth Sleepiness Scale score, overt complications (eg, gastric fistula, bleeding, delayed gastric emptying, wound infection), quality of life, quality of sleep and/or functionality. The systematic review will be conducted according to the recommendations as outlined by the Cochrane collaboration.

ETHICS AND DISSEMINATION

The systematic review and meta-analysis will include published data available online and thus ethics approval will not be required. The findings will be disseminated and published in a peer-reviewed journal. Review updates will be conducted if there is new evidence that may cause any change in review conclusions. Any changes to the study protocol will be updated in the PROSPERO trial registry accordingly.

PROSPERO REGISTRATION NUMBER

CRD42017081743.

Effects of obesity therapies on sleep disorders

Obesity is a significant risk factor for obstructive sleep apnea syndrome (OSAS), and has also been linked to reductions in sleep quality and quantity. Weight loss has been shown to be an effective treatment for improving OSAS; however, there is a high degree of variability in improvements of OSAS in response to weight loss. There are three modalities of obesity therapies: 1) lifestyle modification, which includes changes in dietary intake and physical activity, along with behavioral interventions; 2) pharmacologic agents; and 3) bariatric surgery. Individuals have a highly variable response to the various obesity interventions, and maintenance of weight loss can be especially challenging. These factors influence the effect of weight loss on sleep disorders. There is still a need for large, well-controlled studies examining short- and long-term efficacy of weight loss modalities and their impact on long-term treatment of OSAS and other sleep parameters, particularly in youth. Nonetheless, given our current knowledge, weight reduction should always be encouraged for people coping with obesity, OSAS, and/or sleep disruptions and resources identified to assist patients in choosing a weight loss approach that will benefit them the most.

Effects of a lifestyle intervention on REM sleep-related OSA severity in obese individuals with type 2 diabetes

The aim of this study was to determine if an intensive lifestyle intervention (ILI) reduces the severity of obstructive sleep apnea (OSA) in rapid-eye movement (REM) sleep, and to determine if longitudinal changes in glycaemic control are related to changes in OSA severity during REM sleep over a 4-year follow-up. This was a randomized controlled trial including 264 overweight/obese adults with type 2 diabetes (T2D) and OSA. Participants were randomized to an ILI targeted to weight loss or a diabetes support and education (DSE) control group. Measures included anthropometry, apnea-hypopnea index (AHI) during REM sleep (REM-AHI) and non-REM sleep (NREM-AHI) and glycated haemoglobin (HbA1c) at baseline and year 1, year 2 and year 4 follow-ups. Mean baseline values of REM-AHI were significantly higher than NREM-AHI in both groups. Both REM-AHI and NREM-AHI were reduced significantly more in ILI versus DSE, but these differences were attenuated slightly after adjustment for weight changes. Repeated-measure mixed-model analyses including data to year 4 demonstrated that changes in HbA1c were related significantly to changes in weight, but not to changes in REM-AHI and NREM-AHI. Compared to control, the ILI reduced REM-AHI and NREM-AHI during the 4-year follow-up. Weight, as opposed to REM-AHI and NREM-AHI, was related to changes in HbA1c. The findings imply that weight loss from a lifestyle intervention is more important than reductions in AHI for improving glycaemic control in T2D patients with OSA.

Actigraphy Measured Sleep Indices and Adiposity: The Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

To investigate the cross-sectional relationship between objectively measured sleep characteristics and multiple indices of adiposity in racially/ethnically diverse older adults within the MESA Sleep study (n = 2,146).

METHODS

7-day actigraphy was used to assess sleep duration, sleep efficiency, and night-to-night variability. Body mass index (BMI), waist circumference, and total body fat were modeled continuously and according to obesity cut-points. Models were adjusted for demographic, socioeconomic, and behavioral variables.

RESULTS

Participants who slept less than 6 hours a night had significantly higher BMI, waist circumference, and body fat relative to those who slept 7-8 hours. Those who slept less than 5 hours had a 16% higher prevalence of general obesity (BMI ≥ 30 vs. < 25 kg/m(2)) (95% [CI]: 0.08-0.24) and a 9% higher prevalence of abdominal obesity (waist circumference: women ≥ 88 centimeters, men ≥ 102 centimeters; 95% CI: 0.03-0.16) compared to those who slept 7-8 hours. Results were similar for sleep efficiency and night-to-night sleep variability.

CONCLUSIONS

Among an older multi-ethnic cohort, we found robust associations across multiple indices of sleep and adiposity. Targeting sleep characteristics may be of benefit in obesity interventions, but more research is needed to rule out reverse causality.

Laparoscopic Sleeve Gastrectomy Improves Excessive Daytime Sleepiness and Sleep Quality 6 Months Following Surgery: A Prospective Cohort Study

Introduction

Obstructive sleep apnea (OSA) is one of the most important co-morbid conditions related with morbid obesity. Bariatric procedures are associated with significant improvement in OSA. The aim of the current study was to evaluate the effect of bariatric surgery on daytime sleepiness and quality of sleep in patients that had undergone laparoscopic sleeve gastrectomy.

Methods

Fifty-nine patients were prospectively enrolled in the study. Pre-operative and post-operative (6 months) demographics, medical history, weight, and height of the patients were recorded, and patients were asked to complete Pittsburg Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. OSA screenings were performed using the STOP-Bang questionnaire.

Results

The mean age of the patients was 37.1 ± 1.2 years and 76% were female. Pre-operative and post-operative median (range) BMIs were 47 kg/m² (39–67 kg/m²) and 35 kg/m² (25–44 kg/m²), respectively (P < 0.001). The mean ± standard deviation excess weight loss was 51.6 ± 13.2%. In univariate analysis, total PSQI, STOP-Bang, and ESS scores were found to significantly improve 6 months after surgery (all P < 0.001). Multivariate mixed-model analysis showed a high correlation between the decrease in BMI and all key predictors. Mixed-model analysis revealed that every 1 kg/m² decrease in BMI was associated with a 0.32, 0.13, and 0.26 improvements in PSQI, STOP-Bang, and ESS scores, respectively (all P < 0.001).

Conclusion

Laparoscopic sleeve gastrectomy is associated with rapid weight loss and improvements in sleep quality, daytime sleepiness, and the risk of OSA 6 months after surgery.