Telemonitoring-guided ambulatory fixed CPAP titration versus ambulatory APAP titration in moderate obstructive sleep apnea: A non-inferiority randomized controlled trial

The present study aimed to evaluate whether titration of fixed continuous positive airway pressure at home using telemonitoring produces patient outcomes equal to auto-adjusting positive airway pressure titration at home for patients with moderate obstructive sleep apnea. Patients were randomized with a 1:1 allocation ratio to receive either auto-adjusting positive airway pressure titration based on the median of the 95th percentile pressure across seven nights or fixed continuous positive airway pressure titration based on a fixed calculated pressure and specific adaptations after telemonitoring of device data after 3 and 7 nights. The results of the ambulatory titration were evaluated with in-laboratory polysomnography after 2 weeks. We hypothesized that fixed continuous positive airway pressure titration would be non-inferior to auto-adjusting positive airway pressure titration in respect to continuous positive airway pressure adherence at a 3-month follow-up. A non-inferiority margin of -0.75 hr was prespecified. One-hundred and four patients were randomly allocated to fixed continuous positive airway pressure (n = 52) and auto-adjusting positive airway pressure (n = 52) titration. The mean difference and the 95% confidence intervals in continuous positive airway pressure adherence after 3 months between the two arms were 0.80 (-0.08, 1.69) hr. The non-inferiority hypothesis was confirmed as the lower one-sided 97.5% confidence interval for the mean difference was above the prespecified margin. Patients in the fixed continuous positive airway pressure titration arm were titrated at significantly lower pressure level and had a significantly lower amount of average leaks compared with auto-adjusting positive airway pressure-titrated patients, while there was no difference in residual obstructive apnea-hypopnea index on polysomnography. Telemonitoring enables ambulatory continuous positive airway pressure titration with fixed pressure that is non-inferior to ambulatory titration with auto-adjusting pressure in patients with moderate obstructive sleep apnea.

Beneficial Effects of Early Intervention Telemedicine-based Follow-Up in Sleep Apnea: A Randomized Controlled Multicenter Trial

Rationale: Positive airway pressure (PAP) is standard treatment for obstructive sleep apnea. Telemedicine has been introduced for improved PAP follow-up. Objectives: Our study aim was to evaluate the clinical utility of and patient satisfaction with PAP follow-up with an early intervention telemedical protocol. Methods: A randomized controlled trial was conducted at four sleep clinics of the same county. Treatment-naive patients with obstructive sleep apnea were randomized to standard PAP follow-up (203 patients, fixed follow-up procedures) or early intervention telemedical follow-up (AirView, ResMed; 206 patients, continuous follow-up) for 3 months. Evaluated variables included PAP adherence at 3 months, patient-reported outcome measures (Epworth Sleepiness Scale, 36-item Short Form Health Survey, Insomnia Severity Index, Hospital Anxiety and Depression Scale), and staff time. Group differences were analyzed with linear mixed regression models adjusted for age, body mass index, apnea-hypopnea index, and study center. Results: The study groups were comparable at baseline (N = 409; mean age, 59 ± 12 yr; body mass index, 31.9 ± 6 kg/m2, apnea-hypopnea index, 41.5 ± 21 events/h). PAP adherence was higher in the proactive telemedicine group than in the control group (4.3 ± 2.4 and 4.1 ± 2.6 h/night; P = 0.01, respectively), and mean mask pressure at follow-up was significantly lower in the telemedicine group than in the control group (8.7 ± 2.1 cm H2O vs. 9.2 ± 2.5 cm H2O; P = 0.028). In post hoc analysis, the difference in PAP adherence between groups was most pronounced in patients with depression (4.8 ± 2.6 h/night vs. 2.7 ± 2.3 h/night; P = 0.03). Relevant mask leakage (>24 L/min) was lower in the telemedicine group (5.4% vs. 12.1%, P = 0.024). Improvement of patient-reported outcome measures and patient satisfaction was equivalent between groups. Conclusions: Proactive telemedical management of the initial follow-up of PAP treatment compared favorably with conventional follow-up in terms of adherence, pressure level, and mask leakage. Patients with depression may particularly benefit from telemedical follow-up. Specific clinical routines are required to establish this practice in sleep clinics. Clinical trial registered with www.clinicaltrials.gov (NCT03446560).

Optimal Continuous Positive Airway Pressure Treatment of Obstructive Sleep Apnea Reduces Daytime Resting Heart Rate in Prediabetes: A Randomized Controlled Study

Background It has been widely recognized that obstructive sleep apnea (OSA) is linked to cardiovascular disease. Yet, randomized controlled studies failed to demonstrate a clear cardiovascular benefit from OSA treatment, mainly because of poor adherence to continuous positive airway pressure (CPAP). To date, no prior study has assessed the effect of CPAP treatment on daytime resting heart rate, a strong predictor of adverse cardiovascular outcomes and mortality. Methods and Results We conducted a randomized controlled study in 39 participants with OSA and prediabetes, who received either in-laboratory all-night (ie, optimal) CPAP or an oral placebo for 2 weeks. During daytime, participants continued daily activities outside the laboratory. Resting heart rate was continuously assessed over 19 consecutive days and nights using an ambulatory device consisting of a single-lead ECG and triaxis accelerometer. Compared with placebo, CPAP reduced daytime resting heart rate (treatment difference, -4.1 beats/min; 95% CI, -6.5 to -1.7 beats/min; P=0.002). The magnitude of reduction in daytime resting heart rate after treatment significantly correlated with the magnitude of decrease in plasma norepinephrine, a marker of sympathetic activity (r=0.44; P=0.02), and the magnitude of decrease in OSA severity (ie, apnea-hypopnea index [r=0.48; P=0.005], oxygen desaturation index [r=0.50; P=0.003], and microarousal index [r=0.57; P<0.001]). Conclusions This proof-of-concept randomized controlled study demonstrates, for the first time, that CPAP treatment, when optimally used at night, reduces resting heart rate during the day, and therefore has positive cardiovascular carry over effects. These findings suggest that better identification and treatment of OSA may have important clinical implications for cardiovascular disease prevention. Registration URL: https:/// www.clini​caltr​ials.gov; Unique identifier: NCT01156116.

Strategies to augment adherence in the management of sleep-disordered breathing

Continuous positive airway pressure (CPAP) is highly effective in treating sleep-disordered breathing (SDB). However, unlike surgical interventions, this treatment modality relies heavily on patient acceptance and adherence. The current definition of adherence is largely arbitrary and is mainly used by third-party payers to determine CPAP reimbursement but CPAP adherence remains sub-optimal. Strategies to augment adherence, especially early in the course of a CPAP trial, are needed in the management of SDB. An understanding of the basis for observed differences in CPAP and oral appliance (OA) use is necessary in developing these strategies, but to date no single factor has been consistently identified. Consequently, a multidimensional approach using educational, behavioural, technological and potentially pharmacological strategies to target (i) disease characteristics, (ii) patient characteristics including psychosocial factors, (iii) treatment protocols and (iv) technological devices and side effects that may influence adherence, is likely required to augment the complex behaviour of CPAP and OA use. In the near future, we envision a personalized medicine approach to determine the risk of non-adherence and set individualized adherence goals aimed at treating specific symptoms (e.g. excessive daytime sleepiness) and reducing the risk of patient-specific SDB consequences (e.g. atherosclerosis). Resources for interventions to improve adherence such as educational programmes and telemedicine encounters could then be more efficiently allocated.

Nonadherence to CPAP Associated With Increased 30-Day Hospital Readmissions

STUDY OBJECTIVES

The primary objective of this study was to determine if nonadherence to continuous positive airway pressure (CPAP) is associated with increased 30-day all-cause, cardiovascular-cause, and pulmonary-cause hospital readmissions.

METHODS

Retrospective cohort study at a Veterans Affairs hospital of patients with obstructive sleep apnea (OSA) who were hospitalized from January 1, 2007 to December 31, 2015. Odds ratio of 30-day readmission was calculated for all-cause, cardiovascular-cause, and pulmonary-cause readmissions. Logistic regression model was used to evaluate odds of nonadherent versus adherent group while adjusting for age, sex, body mass index, living situation, race, comorbidities, and medication adherence.

RESULTS

Out of 2,077 records reviewed, 345 patients (183 adherent and 162 nonadherent) met our inclusion criteria. The adherent group had a total of 215 initial admissions, and the nonadherent group had a total of 268 index admissions. Thirty-day all-cause readmission rate was significantly higher in the nonadherent group, with an adjusted odds ratio (OR) of 3.52 (95% confidence interval [CI], 2.04-6.08, P < .001). Thirty-day cardiovascular-cause readmission rate was significantly higher in the nonadherent group, with an adjusted OR of 2.31 (95% CI, 1.11-4.78, P = .024). Difference in 30-day pulmonary-cause readmissions was not statistically significant, with an adjusted OR of 3.66 (95% CI, 0.41-32.76, P = .25).

CONCLUSIONS

Nonadherence to CPAP is associated with increased 30-day all-cause and cardiovascular-cause readmission in patients with OSA. Ensuring CPAP adherence is crucial in addressing general and cardiovascular-related healthcare utilization and morbidity in patients with OSA.

COMMENTARY

A commentary on this article appears in this issue on page 161.

Variability of breathing during wakefulness while using CPAP predicts adherence

BACKGROUND AND OBJECTIVE

The standard therapy for obstructive sleep apnoea (OSA) is continuous positive airway pressure (CPAP) therapy. However, long-term adherence remains at ~50% despite improvements in behavioural and educational interventions. Based on prior work, we explored whether regularity of breathing during wakefulness might be a physiologic predictor of CPAP adherence.

METHODS

Of the 117 consecutive patients who were diagnosed with OSA and prescribed CPAP, 79 CPAP naïve patients were enrolled in this prospective study. During CPAP initiation, respiratory signals were collected using respiratory inductance plethysmography while wearing CPAP during wakefulness in a seated position. Breathing regularity was assessed by the coefficient of variation (CV) for breath-by-breath estimated tidal volume (V_T ) and total duration of respiratory cycle (Ttot). In a derivation group (n = 36), we determined the cut-off CV value which predicted poor CPAP adherence at the first month of therapy, and verified the validity of this predetermined cut-off value in the remaining participants (validation group; n = 43).

RESULTS

In the derivation group, the CV for estimated V_T was significantly higher in patients with poor adherence than with good adherence (median (interquartile range): 44.2 (33.4-57.4) vs 26.0 (20.4-33.2), P < 0.001). The CV cut-off value for estimated V_T for poor CPAP adherence was 34.0, according to a receiver-operating characteristic (ROC) curve. In the validation group, the CV value for estimated V_T >34.0 confirmed to be predicting poor CPAP adherence (sensitivity, 0.78; specificity, 0.83).

CONCLUSION

At the initiation of therapy, breathing regularity during wakefulness while wearing CPAP is an objective predictor of short-term CPAP adherence.

Obstructive sleep apnea and endothelial progenitor cells

BACKGROUND

Obstructive sleep apnea (OSA) occurs in 4% of middle-aged men and 2% of middle-aged women in the general population, and the prevalence is even higher in specific patient groups. OSA is an independent risk factor for a variety of cardiovascular diseases. Endothelial injury could be the pivotal determinant in the development of cardiovascular pathology in OSA. Endothelial damage ultimately represents a dynamic balance between the magnitude of injury and the capacity for repair. Bone marrow-derived endothelial progenitor cells (EPCs) within adult peripheral blood present a possible means of vascular maintenance that could home to sites of injury and restore endothelial integrity and normal function.

METHODS

We summarized pathogenetic mechanisms of OSA and searched for available studies on numbers and functions of EPCs in patients with OSA to explore the potential links between the numbers and functions of EPCs and OSA. In particular, we tried to elucidate the molecular mechanisms of the effects of OSA on EPCs.

CONCLUSION

Intermittent hypoxia cycles and sleep fragmentation are major pathophysiologic characters of OSA. Intermittent hypoxia acts as a trigger of oxidative stress, systemic inflammation, and sympathetic activation. Sleep fragmentation is associated with a burst of sympathetic activation and systemic inflammation. In most studies, a reduction in circulating EPCs has emerged. The possible mechanisms underlying the decrease in the number or function of EPCs include prolonged inflammation response, oxidative stress, increased sympathetic activation, physiological adaptive responses of tissue to hypoxia, reduced EPC mobilization, EPC apoptosis, and functional impairment in untreated OSA. Continuous positive airway pressure (CPAP) therapy for OSA affects the mobilization, apoptosis, and function of EPCs through preventing intermittent hypoxia episodes, improving sleep quality, and reducing systemic inflammation, oxidative stress levels, and sympathetic overactivation. To improve CPAP adherence, the medical staff should pay attention to making the titration trial a comfortable first CPAP experience for the patients; for example, using the most appropriate ventilators or proper humidification. It is also important to give the patients education and support about CPAP use in the follow-up, especially in the early stage of the treatment.