Application of Inverse-Probability-of-Treatment Weighting to Estimate the Effect of Daytime Sleepiness in Patients with Obstructive Sleep Apnea.

Rationale: Continuous positive airway pressure (CPAP), the first line therapy for obstructive sleep apnea (OSA), is considered effective in reducing daytime sleepiness. Its efficacy relies on adequate adherence, often defined as >4 hours per night. However, this binary threshold may limit our understanding of the causal effect of CPAP adherence and daytime sleepiness, and a multilevel approach for CPAP adherence can be more appropriate. Objectives: In this study, we show how two causal inference methods can be applied on observational data for the estimation of the effect of different ranges of CPAP adherence on daytime sleepiness as measured by the Epworth Sleepiness Scale (ESS). Methods: Data were collected from a large prospective observational French cohort for patients with OSA. Four groups of CPAP adherence were considered (0-4, 4-6, 6-7, and 7-10 h per night). Multivariable regression, inverse-probability-of-treatment weighting (IPTW), and inverse propensity weighting with regression adjustment (IPW-RA) were used to assess the impact of CPAP adherence level on daytime sleepiness. Results: In this study, 9,244 patients with OSA treated by CPAP were included. The mean initial ESS score was 11 (±5.2), with a mean reduction of 4 points (±5.1). Overall, there was evidence of the causal effect of CPAP adherence on daytime sleepiness which was mainly observed between the lower CPAP adherence group (0-4 h) compared with the higher CPAP adherence group (7-10 h). There are no differences by considering higher level of CPAP adherence (>4 h). Conclusions: We showed that IPTW and IPW-RA can be easily implemented to answer questions regarding causal effects using observational data when randomized trials cannot be conducted. Both methods give a direct causal interpretation at the population level and allow the assessment of the appropriate consideration of measured confounders.

Symptomatic response to CPAP in obstructive sleep apnea versus COPD- obstructive sleep apnea overlap syndrome: Insights from a large national registry.

BACKGROUND: The symptomatic response to continuous positive airway pressure (CPAP) therapy in COPD-obstructive sleep apnea overlap syndrome (OVS) compared to OSA syndrome (OSA) alone has not been well studied so far. The aim of this study is to explore main differences in the clinical response to CPAP treatment in OVS compared to OSA alone. STUDY DESIGN AND METHODS: Using prospective data from the French National Sleep Apnea Registry, we conducted an observational study among 6320 patients with moderate-to-severe OSA, available spirometry, and at least one follow-up visit under CPAP therapy. RESULTS: CPAP efficacy measured on the residual apnea-hypopnea index and median adherence were similar between OVS and OSA patients. In both groups, the overall burden of symptoms related to sleep apnea improved with CPAP treatment. In a multivariable model adjusted for age, gender, body mass index, adherence to treatment and residual apnea-hypopnea index, OVS was associated with higher odds for persistent morning headaches (OR: 1.37 [95% CI; 1.04; 1.79]; P = 0.02), morning tiredness (OR: 1.33 [95% CI: 1.12; 1.59]; P<0.01), daytime sleepiness (OR; 1.24 [95% CI: 1.4; 1.46]: P<0.01) and exertional dyspnea (OR: 1.26 [95% CI: 1.00;1.58]; P = 0.04) when compared with OSA alone. INTERPRETATION: CPAP therapy was effective in normalizing the apnea-hypopnea index and significantly improved OSA-related symptoms, regardless of COPD status. CPAP should be offered to patients with OVS on a trial basis as a significant improvement in OSA-related symptoms can be expected, although the range of response may be less dramatic than in OSA alone.

Detecting COVID-19 and other respiratory infections in obstructive sleep apnoea patients through CPAP device telemonitoring.

OBJECTIVE: The earliest possible detection of individuals with COVID-19 has been essential to curb the spread of infection. Existing digital tools have been scaled up to address this issue. Every night telemonitoring data on continuous positive airway pressure (CPAP) device use, the first-line therapy for obstructive sleep apnoea (OSA), is collected worldwide. We asked whether the changes in CPAP adherence patterns of might constitute an alert for COVID-19. METHODS: We analysed preliminary results of telemonitoring data, recorded between February 1 and April 30, 2020, on OSA patients followed by our sleep clinics and diagnosed with COVID-19. RESULTS: CPAP telemonitoring data from the first 19 patients diagnosed with COVID-19 showed a clear decrease or halt in adherence in the 20 days immediately preceding COVID-19 diagnosis compared to an earlier period (p < 0.01). CONCLUSION: Patterns of continuous positive airway pressure device use by obstructive sleep apnoea patients collected through telemonitoring can indicate the onset of COVID-19 symptoms. Existing telemonitoring platforms could be immediately used to screen for COVID-19, and for other respiratory infections, in this large at-risk population.

Continuous positive airway pressure-treated patients' behaviours during the COVID-19 crisis.

The #COVID19 pandemic has had limited impact on CPAP use by obstructive sleep apnoea patients. Mainly only those with suspected or proven COVID-19 stopped CPAP use, sometimes without a physician's advice, and were more likely to move to a separate bedroom. https://bit.ly/2RxQDZO.

The Somatotropic Axis in the Sleep Apnea-Obesity Comorbid Duo.

Background: Growth hormone (GH) stimulates the production of insulin-like growth factor 1 (IGF-1) in most tissues and together GH and IGF-1 profoundly impact adipose tissue deposition, glucose metabolism and cardiovascular function. A low serum IGF-I level has been reported as being associated with obstructive sleep apnea (OSA) and might be one of the mechanisms underlying cardio-metabolic risk in OSA patients. Methods: In a multicenter national study, 817 patients consulting for suspicion of OSA (OSA confirmed for 567 patients) underwent serum IGF-1 measurements. We analyzed the association between an IGF-1 level below the median value of the population and variables related to cardio-metabolic risk: body mass index (BMI) and waist circumference, apnea hypopnea index (AHI), cholesterol and triglycerides (expressed as median and divided into quartiles for continuous variables). Results: After adjustment for age and gender, low IGF-1 levels were associated with increased BMI and AHI (Odds ratios (OR) = 2.83; p < 0.0001 and OR = 3.03, p < 0.0001 for Quartile 4 vs. Quartile1, respectively), with elevated cholesterol levels (OR = 1.36, p = 0.0444), and elevated triglyceride levels (OR = 1.36; p = 0.0008). Conclusions: Both adiposity and sleep apnea synergistically predict low levels of IGF-1 and thus could together contribute toward cardio-metabolic risk. Further work are needed to confirm whether IGF-1 levels allow grading severity and predicting response to treatments to aim at a personalized medicine for patients suffering from OSA.

Clinical presentation and comorbidities of obstructive sleep apnea-COPD overlap syndrome.

BACKGROUND: More advanced knowledge is needed on how COPD alters the clinical presentation of obstructive sleep apnea (OSA) and how the association of both diseases, known as 'overlap syndrome' (OVS), impacts on cardiovascular health. OBJECTIVE: To investigate differences between patients with OVS and those with moderate-to-severe OSA alone. METHODS: A cross-sectional study conducted in the French National Sleep Apnea Registry between January 1997 and January 2017. Univariable and multivariable logistic regression models were used to compare OVS versus OSA alone on symptoms and cardiovascular health. RESULTS: 46,786 patients had moderate-to-severe OSA. Valid spirometry was available for 16,466 patients: 14,368 (87%) had moderate-to-severe OSA alone and 2098 (13%) had OVS. A lower proportion of OVS patients complained of snoring, morning headaches and excessive daytime sleepiness compared to OSA alone (median Epworth Sleepiness Scale score: 9 [interquartile range (IQR) 6-13] versus 10 (IQR 6-13), respectively; P <0.02). Similarly, a lower proportion of OVS patients (35.6% versus 39.4%, respectively; P <0.01) experienced sleepiness while driving. In contrast, 63.5% of the OVS population experienced nocturia compared to 58.0% of the OSA population (P<0.01). Apnea hypopnea index (36 [25; 52] vs 33.1 [23.3; 50]), oxygen desaturation index (28 [15; 48] vs 25.2 [14; 45]) and mean nocturnal SaO2 (92 [90; 93.8] vs 93 [91.3; 94]) were significantly more altered in the OVS group. Associated COPD had no effect on the prevalence of hypertension and stroke. After controlling for main confounders, COPD severity was associated in a dose-response relationship with a higher prevalence of coronary heart disease, heart failure and peripheral arteriopathy. CONCLUSIONS: In adults with moderate-to-severe OSA, OVS was minimally symptomatic, but exhibited higher odds for prevalent coronary heart disease, heart failure and peripheral arteriopathy.

Impact of a Multimodal Telemonitoring Intervention on CPAP Adherence in Symptomatic OSA and Low Cardiovascular Risk: A Randomized Controlled Trial.

BACKGROUND: One of the major challenges in treating OSA is to achieve adequate CPAP adherence. Telemonitoring has the potential to provide individualized management and early recognition of problems during treatment. RESEARCH QUESTION: What is the effect of a multimodal telemonitoring intervention on treatment adherence, quality of life, and functional status in symptomatic patients with OSA and low cardiovascular risk? STUDY DESIGN AND METHODS: In a multicenter, randomized controlled trial, patients newly diagnosed with OSA were randomly assigned to multimodal telemonitoring for 6 months vs usual care (UC). Telemonitoring consisted of built-in electronic alert algorithms for early adjustment of CPAP treatment in case of side effects, leaks, or persistent residual events. The primary outcome was CPAP adherence (in hours per night). Secondary outcomes included daily symptoms such as fatigue and sleepiness, and quality of life measured by using self-reported questionnaires. RESULTS: A total of 206 patients with OSA and a median age of 50.6 years (interquartile range [IQR], 42.1; 58.1 years) were included in the study; they were predominantly male (63%) with a median BMI of 30.6 kg/m2 (IQR, 26.8; 35.1 kg/m2) and a median apnea-hypopnea index of 45.2 events/h (IQR, 34.0; 60.0 events/h). Of these, 102 received UC and 104 received telemonitoring. After 6 months of treatment, CPAP adherence was similar in the two groups when assessed either by mean duration of usage (4.73 ± 2.48 h per night in the telemonitoring group and 5.08 ± 2.44 h per night in the UC group; P = .30) or in percentage of patients adherent to treatment (> 4 h usage per night, > 70% nights; 64% in the telemonitoring group vs 72% in the UC group; P = .24). There was no significant difference between the groups in effect size of improvement in fatigue and sleepiness. INTERPRETATION: In patients with severe OSA and low cardiovascular risk, multimodal telemonitoring did not increase CPAP adherence. For both the telemonitoring and UC groups, similar improvements in daytime symptoms were achieved. TRIAL REGISTRY: ClinicalTrials.gov; No.: 01796769; URL: www.clinicaltrials.gov.

Who May Benefit From Diuretics in OSA?: A Propensity Score-Match Observational Study.

BACKGROUND: Diuretics have been reported as effective for reducing OSA severity by preventing fluid retention and reducing rostral fluid shift. The benefit of diuretics might vary depending on the OSA clinical phenotype and comorbidities. To test this hypothesis, we conducted a propensity score-matched cohort analysis of data from the French national sleep apnea registry "Observatoire Sommeil de la Fédération de Pneumologie." RESEARCH QUESTION: Which phenotypic subtypes of OSA may benefit from diuretics? STUDY DESIGN AND METHODS: A propensity score analysis was used to determine the impact of diuretics on OSA severity. Matching (ratio 1:4) was performed by using a 0.1 collider for the propensity score. Severe OSA was defined as an apnea-hypopnea index (AHI) > 30 events/h, and the usefulness of diuretics was assessed by using a logistic regression model. RESULTS: The 69,564 OSA patients studied in the OSFP prospective observational cohort had a median age of 56.9 years (interquartile range: 47.4; 65.6), 67% were men, and the median AHI was 28 (14; 43) events/h. Among them, 9,783 (14.1%) were treated with diuretics. Diuretics reduced OSA severity in overweight or moderately obese patients (P = .03) and in patients with hypertension (P < .01), particularly in patients with hypertension with a BMI between 25 and 35 (P < .01). Diuretics had no significant effect on OSA severity in patients with self-reported low physical activity or heart failure. INTERPRETATION: Diuretics appear to have a positive impact on OSA severity in overweight or moderately obese patients with hypertension. A prospective study is needed to confirm that diuretics are of interest in combined therapies for hypertensive patients with OSA.

Partial failure of CPAP treatment for sleep apnoea: Analysis of the French national sleep database.

BACKGROUND AND OBJECTIVE: Continuous positive airway pressure (CPAP) is the first-line therapy for obstructive sleep apnoea (OSA). Residual apnoea and/or hypopnoea events, that is an apnoea-hypopnoea index (AHI) > 5, during CPAP contribute to treatment drop-out. The clinical scenarios triggering residual events during CPAP use are poorly described. Underlying co-morbidities, especially cardiovascular diseases, lifestyle factors, OSA characteristics at diagnosis and type of mask have been suggested as potential contributors. METHODS: Patients from the prospective French sleep apnoea registry diagnosed with OSA (AHI ≥ 15 events/h) treated with CPAP were included. Logistic regression analysis identified factors associated with a risk of residual AHI > 5 events/h on CPAP. RESULTS: The 12 285 OSA patients were predominantly men (n = 8715, 70.9%), middle-aged (58.2 (49.8; 66.1) years) and obese (median body mass index: 31.3 (27.7; 35.6) kg/m2 ). Most had an AHI ≤ 5 events/h (n = 9573, 77.9%) versus 22.1% with AHI > 5/h. The latter were less CPAP adherent (5.75 (4.01; 7.00) vs 6.00 (4.53; 7.00) h/night). In multivariable analysis, factors associated with residual AHI >5/h were male sex, age, sedentary lifestyle, OSA severity, cardiovascular co-morbidities (heart failure and arrhythmia) and type of interface (orofacial mask versus nasal mask: OR = 2.15 (95%CI: 1.95; 2.37)). A subgroup analysis found that patients using pressures above 10 cm H2 O were 1.43 (95% CI: 1.3; 1.57) times more likely to have residual AHI > 5/h. CONCLUSION: Knowing about risk factors for residual apnoeic-hypopnoeic events may assist in the timely provision of personalized care including the type of PAP therapy, attention to co-morbidities and choice of interface.

Multimodal Remote Monitoring of High Cardiovascular Risk Patients With OSA Initiating CPAP: A Randomized Trial.

BACKGROUND: The management of patients with high cardiovascular risk and OSA must target not only improving adherence to CPAP, but should also include strategies aimed at reducing BP and increasing physical activity. The study aims to evaluate the effectiveness of an integrated intervention using remote patient telemonitoring in reducing BP in high cardiovascular risk patients with OSA. METHODS: In a multicenter, open, randomized trial, patients with OSA were randomly assigned at CPAP initiation to usual care or multimodal telemonitoring for 6 months. Telemonitoring used electronic equipment collecting information about BP, symptoms, CPAP side effects, and physical activity with home care providers prespecified protocoled actions. The primary effectiveness outcome was assessed using home self-measured BP on 3 consecutive days. Secondary outcomes included CPAP compliance, symptoms, and physical activity. RESULTS: Of 306 patients with a median age of 61.3 years [interquartile range, 54.1; 66.1], who were predominantly men, 226 (74%) with a BMI of 32.0 [28.7; 35.6] kg/m2 and an apnea-hypopnea index of 46 [35; 61] events/h, 149 received usual care and 157 received telemonitoring. After 6 months of CPAP, home self-measured BP did not differ significantly between groups. In secondary analyses, there was no significant difference in steps per day, but a significant increase in CPAP adherence and an improvement in daytime sleepiness and quality of life in favor of the multimodal telemonitoring. CONCLUSIONS: In OSA patients with high cardiovascular risk, multimodal telemonitoring was not superior to usual CPAP care for improving home BP; however, telemonitoring improved adherence and patient-centered outcomes.

Nocturia is an independent predictive factor of prevalent hypertension in obstructive sleep apnea patients.

OBJECTIVE: The aim of this study was to determine whether nocturia is an independent predictor for prevalent hypertension in obstructive sleep apnea (OSA). METHODS: We analyzed data from a national prospective clinical cohort of OSA patients participating in the French national prospective registry. Anthropometric data, comorbidities, OSA severity, and number of voids/night were included in multivariate analyses to determine the independent variables associated with prevalent hypertension. RESULTS: A total of 22,674 OSA patients were included, of which 11,332 were hypertensive. The prevalence of hypertension among OSA patients was about 1.3 times higher in patients suffering from nocturia at 61.45% versus 46.52% in hypertensive and non-hypertensive OSA patients (p <0.001). There was a significant positive relationship between hypertension and the severity of nocturia beyond two voids/night: two voids/night versus none: odds ratio (OR) = 1.270 (95% confidence interval (CI) = 1.175; 1.372), three voids/night versus none: OR = 1.422 (95% CI = 1.293; 1.565), and four voids/night versus none: OR = 1.575 (95% CI = 1.394; 1.781). The strength of the association was enhanced in patients over 64 years of age. CONCLUSIONS: Nocturia is a strong independent predictor of prevalent hypertension in OSA. This association exhibited a "dose-response" relationship beyond two voids/night. The resolution of nocturia after continuous positive airway pressure (CPAP) treatment might be an important outcome to consider for the response of hypertension to CPAP.

Association between glaucoma and sleep apnea in a large French multicenter prospective cohort.

OBJECTIVE: Several reports suggest that glaucoma may be linked to obstructive sleep apnea (OSA). Herein, we investigated this hypothesis in the largest reported sample to date. METHODS: Data were from the French multicenter prospective cohort study including OSA-suspected patients from private practice, general and teaching hospitals. Demographics, history, comorbidities and sleep studies from patients aged >50 years were analyzed. Univariate and multivariate logistic regression were used to predict the odds ratio of prevalent glaucoma depending on sleep apnea status and other potential anthropometric, metabolic, cardiovascular and respiratory confounders. RESULTS: A total of 9580 patients aged >50 years were included. Among these patients, 6754 had sleep apnea and 330 had glaucoma. Glaucoma prevalence was 3.55% in patients with OSA and 3.14% in patients without OSA. OSA diagnosis did not significantly influence the risk of glaucoma in univariate analysis (odds ratio [OR], 1.13; 95% confidence interval [CI], 0.87-1.47). The variables significantly influencing the odds of glaucoma with multivariate regression were age >61.4 years (OR, 1.55; 95% CI, 1.23-1.95), body mass index <30 kg/m2 (OR, 1.58; 95% CI, 1.26-1.99), female gender (OR, 1.40; 95% CI, 1.11-1.78), arterial hypertension (OR, 1.32; 95% CI, 1.05-1.67), high triglyceride levels (OR, 2.03; 95% CI, 1.43-2.88) and thyroid dysfunction (OR, 1.52; 95% CI, 1.09-2.11). CONCLUSIONS: When confounders are taken into account, patients with OSA do not have higher odds of glaucoma compared with patients who do not have OSA in a large multicenter prospective cohort.

Type of mask may impact on continuous positive airway pressure adherence in apneic patients.

RATIONALE: In obstructive sleep apnea patients (OSA), continuous positive airway pressure (CPAP) adherence is crucial to improve symptoms and cardiometabolic outcomes. The choice of mask may influence CPAP adherence but this issue has never been addressed properly. OBJECTIVE: To evaluate the impact of nasal pillows, nasal and oronasal masks on CPAP adherence in a cohort of OSA. METHODS: Newly CPAP treated OSA participating in "Observatoire Sommeil de la Fédération de Pneumologie", a French national prospective cohort, were included between March 2009 and December 2011. Anthropometric data, medical history, OSA severity, sleepiness, depressive status, treatment modalities (auto-CPAP versus fixed pressure, pressure level, interface type, use of humidifiers) and CPAP-related side effects were included in multivariate analysis to determine independent variables associated with CPAP adherence. RESULTS: 2311 OSA (age = 57(12) years, apnea+hypopnea index = 41(21)/h, 29% female) were included. Nasal masks, oronasal masks and nasal pillows were used by 62.4, 26.2 and 11.4% of the patients, respectively. In univariate analysis, oronasal masks and nasal pillows were associated with higher risk of CPAP non-adherence. CPAP non-adherence was also associated with younger age, female gender, mild OSA, gastroesophageal reflux, depression status, low effective pressure and CPAP-related side effects. In multivariate analysis, CPAP non-adherence was associated with the use of oronasal masks (OR = 2.0; 95%CI = 1.6; 2.5), depression, low effective pressure, and side effects. CONCLUSION: As oronasal masks negatively impact on CPAP adherence, a nasal mask should be preferred as the first option. Patients on oronasal masks should be carefully followed.

Residual sleepiness in sleep apnea patients treated by continuous positive airway pressure.

Hypoxic brain damage might explain persistent sleepiness in some continuous positive airway pressure-compliant obstructive sleep apnea called residual excessive sleepiness. Although continuous positive airway pressure may not be fully efficient in treating this symptom, wake-promoting drug prescription in residual excessive sleepiness is no longer allowed by the European Medicines Agency. The aim of this study is to describe residual excessive sleepiness phenotypes in a large prospective sample of patients with obstructive sleep apnea. Residual excessive sleepiness was defined by an Epworth Sleepiness Scale score ≥ 11. Eligible patients from the French National Sleep Registry attending follow-up continuous positive airway pressure visits numbered 1047. Patients using continuous positive airway pressure < 3 h (n = 275), with residual apnea-hypopnea index > 15 h⁻¹ (n = 31) or with major depression were excluded (n = 150). Residual excessive sleepiness prevalence in continuous positive airway pressure-treated obstructive sleep apnea was 13% (18% for those with an initial Epworth Sleepiness Scale score > 11), and significantly decreased with continuous positive airway pressure use (9% in ≥ 6 h night⁻¹ continuous positive airway pressure users, P < 0.005). At the time of diagnosis, patients with residual excessive sleepiness had worse subjective appreciation of their disease (general health scale, Epworth Sleepiness Scale and fatigue score), and complained more frequently of continuous positive airway pressure side-effects. Residual excessive sleepiness prevalence was lower in severe obstructive sleep apnea than in moderate obstructive sleep apnea (11% when AHI > 30 h⁻¹ versus 18% when AHI 15-30, P < 0.005). There was no relationship between residual excessive sleepiness and body mass index, cardiovascular co-morbidities or diabetes. Continuous positive airway pressure improved symptoms in the whole population, but to a lower extent in patients with residual excessive sleepiness (fatigue scale: -5.2 versus -2.7 in residual excessive sleepiness- and residual excessive sleepiness+ patients, respectively, P < 0.001). Residual excessive sleepiness prevalence decreased with continuous positive airway pressure compliance. Hypoxic insult is unlikely to explain residual excessive sleepiness as obstructive sleep apnea severity does not seem to be critical. Residual symptoms are not limited to sleepiness, suggesting a true 'continuous positive airway pressure-resistant syndrome', which may justify treatment by wake-promoting drugs.

Pressure reduction during exhalation in sleep apnea patients treated by continuous positive airway pressure.

INTRODUCTION: This French, multicenter, randomized double-blind controlled trial tested the hypothesis that pressure reduction during exhalation (C-Flex; Respironics; Murrysville, PA) would improve continuous positive airway pressure (CPAP) compliance, comfort, and quality of life. METHODS: Two hundred eighteen newly diagnosed sleep apnea patients (seven centers; mean [+/- SD] age, 55 +/- 11 years; mean body mass index, 31 +/- 6 kg/m(2); mean apnea-hypopnea index, 44 +/- 21 events/h) were randomly assigned to receive 3 months of treatment with CPAP (108 patients) or C-Flex (110 patients). Objective compliance, generic quality-of-life questionnaire (SF-36) scores, disease-specific quality-of-life questionnaire (Grenoble Sleep Apnea Quality of Life [GrenobleSAQOL]) scores, and visual analog scales for CPAP comfort and side effects were determined at baseline and after 3 months. After 3 months, patients in the CPAP arm were moved to the C-Flex arm for 3 additional months (open study). RESULTS: An intention-to-treat analysis demonstrated that there were no differences at 3 months between C-Flex and CPAP use in terms of compliance, the rate of side effects, and comfort. Low compliers receiving CPAP therapy (< 4 h of use) significantly improved this outcome during the open study (p = 0.04). There was a significant improvement in six of eight of the SF-36 domain scores and in all of the domains of the GrenobleSAQOL scores in both groups using either CPAP or C-Flex. CONCLUSION: In unselected sleep apnea patients, C-Flex was associated with similar outcomes to standard CPAP. Low compliers receiving CPAP therapy improved their adherence when moving to C-Flex. TRIAL REGISTRATION: ISRCTN Register Identifier: 08065291.