Mortality and morbidity in obstructive sleep apnoea-hypopnoea syndrome: results from a 30-year prospective cohort study

Cluster-derived obstructive sleep apnea phenotypes and outcomes at 5-year follow-up

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a heterogeneous, complex disease. We aimed to identify OSA phenotypes through cluster analysis and to perform a long-term follow-up to validate the phenotypes.

METHODS

We applied a partitioning around medioids technique in a cohort of 1,217 participants recently diagnosed with OSA. We performed a 5-year follow-up analyzing the incidence of comorbidities, chronic medication, hospital admissions, mortality, and the influence of continuous positive airway pressure treatment on mortality risk.

RESULTS

We identified three phenotypes: two predominantly male clusters, one composed of middle-aged participants with overweight, moderate OSA, and cardiovascular risk factors and the other consisting of older, obese participants with severe OSA, cardiovascular risk factors, ischemic heart disease (18.4%), and atrial fibrillation (9.7%). The third cluster was composed of 77% female participants with moderate OSA; cardiovascular risk factors; the highest prevalence of depression (15.7%); and high prescription of antidepressants (55.1%), anxiolytics (40.0%), hypnotics, sedatives (11.1%), nonsteroidal anti-inflammatory drugs (67.9%), and weak opioids (15.1%). The baseline characteristics of each cluster maintained the same trend over time regarding the incidence of new comorbidities, medication intake, hospitalization rates, and reasons for admission. The absence of continuous positive airway pressure treatment was associated with a significantly higher risk of all-cause mortality (hazard ratio 5.84, confidence interval 2.9-11.8), especially in the older men (hazard ratio 7.7, confidence interval 4.06-14.63) and predominantly female clusters (hazard ratio 2.79, confidence interval 1.34-5.79).

CONCLUSIONS

We identified three phenotypes with relevant clinical and prognostic implications in order to improve personalized strategies in OSA management.

CITATION

Silveira MG, Sampol G, Mota-Foix M, Ferrer J, Lloberes P. Cluster-derived obstructive sleep apnea phenotypes and outcomes at 5-year follow-up. J Clin Sleep Med. 2022;18(2):597-607.

Racial disparity in sleep apnea-related mortality in the United States

BACKGROUND

Sleep apnea is one of the most common sleep disorders in the United States (US). Although the prevalence, risk factors, and clinical presentations of sleep apnea vary by racial groups, the racial disparity in sleep apnea-related mortality remains unclear.

METHODS

Sleep apnea-related mortality for 1999-2019 was obtained from the National Center for Health Statistics provided by the Centers for Disease Control and Prevention. We examined the mortality trends for sleep apnea using Joinpoint regression analysis and compared the associated outcomes and multiple causes of death between Blacks and Whites.

RESULTS

For 1999-2019, sleep apnea was documented as the underlying cause of death in 17,053 decedents, with 2593 Blacks and 14,127 Whites. The overall age-adjusted mortality rates in all population, Blacks, and Whites were 2.5, 3.5, and 2.4 per 1,000,000 population, respectively (P < 0.001). Both Blacks and Whites had the highest mortality rates in the Midwest and the lowest in the Northeast. Despite the flattened mortality trend in the last decade overall, Black males had a continuous mortality increase over the study period (Annual Percentage Change 2.7%, 95% CI: 1.2-4.2). For both genders of sleep apnea decedents, Blacks were more likely to have multiple cause of death of Cardiac Arrest, Hypertension, Obesity, and Chronic Renal Failure, but Arrhythmia was more common in Whites (P < 0.05).

CONCLUSIONS

There is a significant racial disparity in sleep apnea-related mortality in the US. The uptrend in mortality in Black males and associated outcomes related to cardiovascular disease should raise concerns specifically in Blacks with sleep apnea.

CPAP Intervention as an Add-On Treatment to Lipid-Lowering Medication in Coronary Artery Disease Patients with Obstructive Sleep Apnea in the RICCADSA Trial

Dyslipidaemia is a well-known risk factor for coronary artery disease (CAD), and reducing lipid levels is essential for secondary prevention in management of these high-risk individuals. Dyslipidaemia is common also in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) is the first line treatment of OSA. However, evidence of a possible lipid-lowering effect of CPAP in CAD patients with OSA is scarce. We addressed the effect of CPAP as an add-on treatment to lipid-lowering medication in a CAD cohort with concomitant OSA. This study was a secondary analysis of the RICCADSA trial (Trial Registry: ClinicalTrials.gov; No: NCT00519597), that was conducted in Sweden between 2005 and 2013. In total, 244 revascularized CAD patients with nonsleepy OSA (apnea-hypopnea index ≥ 15/h, Epworth Sleepiness Scale score < 10) were randomly assigned to CPAP or no-CPAP. Circulating triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) levels (all in mg/dL) were measured at baseline and 12 months after randomization. The desired TG levels were defined as circulating TG < 150 mg/dL, and LDL levels were targeted as <70 mg/dL according to the recent guidelines of the European Cardiology Society and the European Atherosclerosis Society. A total of 196 patients with available blood samples at baseline and 12-month follow-up were included (94 randomized to CPAP, 102 to no-CPAP). We found no significant between-group differences in circulating levels of TG, TC, HDL and LDL at baseline and after 12 months as well as in the amount of change from baseline. However, there was a significant decline regarding the proportion of patients with the desired TG levels from 87.2% to 77.2% in the CPAP group (p = 0.022), whereas there was an increase from 84.3% to 88.2% in the no-CPAP group (n.s.). The desired LDL levels remained low after 12 months in both groups (15.1% vs. 17.2% in CPAP group, and 20.8% vs. 18.8% in no-CPAP group; n.s.). In a multiple linear regression model, the increase in the TG levels was predicted by the increase in body-mass-index (β = 4.1; 95% confidence interval (1.0-7.1); p = 0.009) adjusted for age, sex and CPAP usage (hours/night). CPAP had no lipid-lowering effect in this revascularized cohort with OSA. An increase in body-mass-index predicted the increase in TG levels after 12 months, suggesting that lifestyle modifications should be given priority in adults with CAD and OSA, regardless of CPAP treatment.

Predictive Factors for Obstructive Sleep Apnea Diagnosis in Bariatric Surgery Candidates with or Without Chronic Insomnia Complaints

OBJECTIVE

This study aims to evaluate the frequency of insomnia complaints in bariatric patients and to assess obstructive sleep apnea (OSA) predictors according to the presence or absence of chronic insomnia.

METHODS

Insomnia was defined as the presence of at least one specific symptom: difficulty falling asleep, difficulty maintaining sleep, and/or waking up earlier than expected. Diagnosis of OSA was objectively obtained from in-laboratory polysomnography. Multivariate logistic regression analysis was used to assess OSA predictors.

RESULTS

This cross-sectional study contains 1,737 bariatric surgery candidates: 59.6% without insomnia and 40.4% with insomnia. OSA prevalence was similar among participants with or without insomnia either for any OSA (p = 0.168) or for moderate-to-severe OSA (p = 0.185). Patients without insomnia showed a higher prevalence of severe OSA than those with insomnia (p = 0.005). In both cohorts, five parameters were independent OSA predictors: sex, age, body mass index (BMI), neck circumference (NC), and excessive daytime sleepiness (EDS). Male sex was the most important predictor, whether in individuals without insomnia (adjusted odds ratio [OR] ranging from 4.874 to 8.369) or in those with insomnia (adjusted OR ranging from 5.672 to 12.441).

CONCLUSIONS

A considerable proportion of bariatric patients report insomnia complaints. The probability of suffering from OSA was similar among bariatric candidates with or without insomnia, except for severe OSA diagnosis. Sex, age, BMI, NC, and EDS were independent predictors for OSA diagnosis irrespective of insomnia symptoms, and male sex was the main predictor for OSA in bariatric individuals with or without insomnia.

Effect of nocturnal hypoxemia on glycemic control among diabetic Saudi patients presenting with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a prevalent disease that is associated with an increased incidence of type II diabetes mellitus (DM) if left untreated. We aimed to determine the association between glycosylated hemoglobin (HbA1c) levels and both nocturnal hypoxemia and apnea-hypopnea index (AHI) among a Saudi patients with OSA.

METHODS

A cross-sectional study that enrolled 103 adult patients diagnosed with DM and confirmed to have OSA by full night attended polysomnography between 2018 and 2021. Those who presented with acute illness, chronic obstructive pulmonary disease (COPD)/restrictive lung diseases causing sleep-related hypoxemia, or no available HbA1c level within 6 months before polysomnography were excluded from the study. Univariate and multivariate linear regression analyses between HbA1c levels and parameters of interest were tested.

RESULTS

Sixty-seven (65%) of the studied population had uncontrolled DM (HbA1c ≥7%). In univariate regression analysis, there was a significant positive association between HbA1c, and sleep time spent with an oxygen saturation below 90% (T90), female gender, and body mass index (BMI) (p<0.05) but not AHI, or associated comorbidities (p>0.05). In the multivariate analysis, HbA1c was positively associated with increasing T90 (p<0.05), and ODI (p<0.05), but not with AHI (p>0.05).

CONCLUSION

Nocturnal hypoxemia could be an important factor affecting glycemic control in patients with OSA suffering from DM irrespective of the severity of both diseases.

Influence of nocturnal insomnia symptoms on obstructive sleep apnea diagnosis in a clinical referral cohort

STUDY OBJECTIVES

To assess whether nocturnal symptoms of insomnia influence the prevalence of obstructive sleep apnea (OSA) in a clinical referral cohort.

METHODS

Insomnia was defined by the presence of one or more of the following complaints: difficulty initiating sleep, difficulty maintaining sleep, and/or early morning awakenings. OSA severity was based on an apnea-hypopnea index: ≥ 5.0/h (any OSA), ≥ 15.0/h (moderate/severe OSA), and ≥ 30/h (severe OSA). Multivariate logistic regression analysis was used to evaluate predictive factors for OSA diagnosis and severity.

RESULTS

Overall, 12,021 outpatients referred for polysomnography (PSG) were grouped into two cohorts: without insomnia (58.2%) and with insomnia (41.8%). Individuals without insomnia had a higher prevalence of OSA than those with insomnia (p < 0.001, for all OSA severity levels). The presence of insomnia was negatively associated with diagnosis of any OSA (adjusted odds ratio [OR]: 0.852; 95% confidence interval [CI]: 0.769-0.944), moderate/severe OSA (adjusted OR: 0.819; 95% CI: 0.751-0.892), and severe OSA (adjusted OR: 0.816; 95% CI: 0.746-0.892). Moreover, the number of nocturnal symptoms of insomnia was associated with a lower likelihood of OSA, even when adjusted for other confounders such as sex, age, body mass index, neck circumference, excessive daytime sleepiness, hypertension, and type 2 diabetes mellitus.

CONCLUSIONS

In this present study that included a large sample of consecutive outpatients, there was an inverse relationship between the number of nocturnal symptoms of insomnia and OSA diagnosis.

Validation of the STOP questionnaire as a screening tool for OSA among different populations: a systematic review and meta-regression analysis

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a sleep breathing disorder associated with adverse health outcomes, but it remains largely underdiagnosed. The STOP questionnaire is a simple tool for screening OSA and is widely used in various populations. The objective of this study was to determine the predictive parameters of the STOP questionnaire to detect OSA in sleep clinics, medical population, surgical population, commercial drivers, and the general population.

METHODS

Electronic databases were searched from January 2008 to April 2021. Pooled predictive parameters were recalculated using 2 × 2 contingency tables and random-effects meta-analyses were performed. The combined test characteristics at different OSA severities [any OSA (AHI≥5), moderate-to-severe OSA (AHI≥15), severe OSA (AHI≥30)] were used to compare the accuracy of the STOP questionnaire with polysomnography. The quality of the studies was evaluated using Cochrane Methods criteria.

RESULTS

Twenty-four studies met the inclusion criteria: 16 were in the sleep clinic population (n=8,132), four in medical population (n=1,023), two in the surgical population (n=258), and one study each on commercial drivers (n=85) and general population (n=4,770). A STOP score ≥2 showed excellent sensitivity to the different OSA severities for the sleep clinic population (>89%) and to severe OSA for the medical population (85.6%). In both populations, the STOP questionnaire also had excellent discriminative power to exclude severe OSA [negative predictive values (NPV) >84%]. The pooled sensitivity and NPV for the surgical population with moderate-to-severe OSA was 81% and 75%.

CONCLUSIONS

This meta-analysis suggests that the STOP questionnaire is a valid and effective screening tool for OSA among these population.

[Adherence to CPAP Three Months after Starting Therapy in 1078 Patients with Obstructive Sleep Apnea (OSA)]

INTRODUCTION

 Nocturnal Continuous Positive Airway Pressure (CPAP) is considered the gold standard treatment for obstructive sleep apnoea (OSA). The CPAP therapy is a long-term treatment but does come with few possible side effects. The adherence to the therapy is frequently suboptimal. In this paper, adherence to therapy was assessed and typical problems were classified.

METHODS

 1078 OSA patients received CPAP therapy after a diagnostic polygraphy (PG) or polysomnography (PSG). Adherence to therapy was followed up three months after treatment induction. The following therapy adherence groups were defined: 1. correctly calibrated CPAP and good adherence, 2. CPAP non-acceptance, after initial use, 3. CPAP intolerance use due to side effects, 4. discontinuation due to lack of motivation/low rates of symptoms. 5. mask intolerance, 6. CPAP failure due to a lack of perceived treatment effect, 7. Change to another non-invasive ventilation method, 8. No control carried out.

RESULTS

 Out of 1078 OSA patients a therapy control was performed in 830 patients (77 %). Of these, 450 patients (54.2 %) were placed in group 1, 216 patients (26 %) in group 2, 71 patients (8.5 %) in group 3, 35 patients (4.2 %) in group 4, 14 patients (1.7 %) in group 5, 3 patients (0.4 %) in group 6 and 41 patients (4.9 %) in group 7. A mild obstructive index, low CPAP pressure and, as a trend, a low Epworth- Sleepiness score were predictors of CPAP failure. No significant predictors could be shown for adherence to therapy.

DISCUSSION

 An effective treatment use of 54 % after 3 months is a suboptimal result. Predictors of CPAP failure were parameters that indicated that the patient was less symptomatic prior to therapy. Despite a large patient cohort, neither anthropometric nor PSG-data provided any significant CPAP adherence predictors. Rather, experiences in the first nights of use could be decisive. CPAP devices offer comfort settings that have to be personalised to patients' needs and wants. A large selection of different mask shapes requires experience and training in patient-centred mask fitting. A three-month follow-up appointment seems too long to discuss therapy problems with the patient in a timely manner. Telemedical options or short-term telephone appointments should be considered.

[Chronic obstructive pulmonary disease, sleep-disordered breathing and hypoventilation-Influence on the cardiorenal system]

Comorbidities are frequently observed in patients suffering from pulmonary diseases due to shared risk factors and intricate interactions between various organ systems. This article aims to characterize the effects of selected diseases of the respiratory system on the cardiovascular system and kidneys. Advanced chronic obstructive pulmonary disease (COPD) often leads to a prognostically unfavorable increased pressure in the pulmonary circulation. In this respect treatment of these patients is primarily aimed at the underlying pulmonary disease and targeted treatment of the pulmonary hypertension should only be carried out according to invasive diagnostics and in an individualized manner. So far, the fact that there is a substantial overlap between COPD and heart failure with preserved ejection fraction has been completely ignored, which should be considered in the diagnostic procedure. Obstructive sleep apnea (OSA) has several unfavorable effects on the cardiovascular system and has been identified as an independent risk factor for cardiovascular diseases. The established treatment of OSA with continuous positive airway pressure (CPAP) has been shown to improve daytime sleepiness and the quality of life; however, an effect of CPAP on the occurrence of cardiovascular events, especially in asymptomatic patients, has so far not been demonstrated in randomized trials. Peripheral edema is frequently observed in patients suffering from chronic hypercapnia, which can be explained by several pathophysiological mechanisms, including pulmonary vasoconstriction and a direct effect of the hypercapnia on renal blood flow. Apart from the administration of diuretics, recompensation of such patients always requires treatment of the hypercapnia by noninvasive ventilation.

Intergenic SNPs in Obstructive Sleep Apnea Syndrome: Revealing Metabolic, Oxidative Stress and Immune-Related Pathways

There is strong evidence supporting the contribution of genetic factors to obstructive sleep apnea syndrome (OSAHS) susceptibility. In the current study we analyzed both in a clinical cohort and in silico, four single nucleotide polymorphisms SNPs, rs999944, rs75108997, rs35329661 and rs116133558 that have been associated with OSAHS. In 102 patients with OSAHS and 50 healthy volunteers, genetic testing of the above polymorphisms was performed. Polymorphism rs116133558 was invariant in our study population, whereas polymorphism rs35329661 was more than 95% invariant. Polymorphism rs999944 displayed significant (>5%) variance in our study population and was used in the binary logistic regression model. In silico analyses of the mechanism by which these three SNPs may affect the pathophysiology of OSAHS revealed a transcriptomic network of 274 genes. This network was involved in multiple cancer-associated gene signatures, as well as the adipogenesis pathway. This study, uncover a regulatory network in OSAHS using transcriptional targets of intergenic SNPs, and map their contributions in the pathophysiology of the syndrome on the interplay between adipocytokine signaling and cancer-related transcriptional dysregulation.

Age and comorbidities are crucial predictors of mortality in severe obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) is a highly prevalent disorder. The prognostic role of comorbidity in patients with OSAS and their role for risk stratification remain poorly defined.

METHODS

We studied 1,592 patients with severe OSAS diagnosed by polysomnography. The primary outcome was all-cause mortality. The standardized mortality ratio (SMR) was estimated as the ratio of observed deaths to expected number of deaths in the general population. The expected numbers of deaths were derived using mortality rates from the general Apulian population. The association of comorbidities with all-cause mortality was assessed using multivariable Cox regression analysis. Finally, recursive-partitioning analysis was applied to identify the combinations of comorbidities that were most influential for mortality and to cluster the patients into risk groups according to individual comorbidities RESULTS: During 11,721 person-years of follow-up, 390 deaths (3.33 deaths/100 person-years) occurred. The median follow-up was 7 (4-10) years. The SMR was 1.47 (95% confidence intervals 1.33-1.63). Age, sex, obesity, cardiovascular diseases (CVD), moderate-to-severe chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD) and malignancy were independently associated with mortality risk. Recursive-partitioning analysis allowed distinguishing three clinical phenotypes differentially associated with mortality risk. The combination of CKD with CVDs or with moderate-to-severe COPD conferred the highest risk.

CONCLUSIONS

Severe OSAS is associated with increased risk for all-cause death. Age and comorbidity are crucial predictors of mortality in patients with severe OSAS. Clustering patients according to comorbidities allows identifying clinically meaningful phenotypes.

Prospective Trial of CPAP in Community-Dwelling Adults with Down Syndrome and Obstructive Sleep Apnea Syndrome

Adults with Down syndrome (DS) are predisposed to obstructive sleep apnoea (OSA), but the effectiveness and acceptability of continuous positive airway pressure treatment (CPAP) in this group has rarely been formally assessed. This study was designed as a pilot randomised, parallel controlled trial for one month, continuing as an uncontrolled cohort study whereby the control group also received the intervention. Symptomatic, community-dwelling DS individuals exhibiting ≥10 apnoeas/hypopneas per hour in bed on a Type 3 home sleep study were invited to participate in this study, with follow-up at 1, 3, 6, and 12 months from baseline. Measurements of sleepiness, behaviour, cognitive function and general health were undertaken; the primary outcome was a change in the pictorial Epworth Sleepiness Scale (pESS) score. Twenty-eight participants (19 male) were enrolled: age 28 ± 9 year; body mass index 31.5 ± 7.9 kg/m2; 39.6 ± 32.2 apnoeas/hypopneas per hour in bed; pESS 11 ± 6/24. The pilot randomised controlled trial at one month demonstrated no change between the groups. At 12 months, participant (p = 0.001) pESS and Disruptive (p < 0.0001), Anxiety/Antisocial (p = 0.024), and Depressive (p = 0.008) behaviour scores were reduced compared to baseline. Improvement was noted in verbal (p = 0.001) and nonverbal intelligence scores (p = 0.011). General health scores also improved (p = 0.02). At the end of the trial, 19 participants continued on treatment. Use of CPAP in adults with DS and OSA led to a number of significant, sustained improvements in sleepiness and behavioural/emotional outcomes at 12 months.