A comparison of two obesity-related hypoventilation disorders: Impact on sleep, quality of life and neurocognitive outcomes and the effects of positive airway pressure therapy.

Study Objectives: Symptom impact and neurocognitive function have not been previously compared between patients with obesity-associated hypoventilation disorders (obesity hypoventilation syndrome [OHS]) and hypoventilation in the setting of obesity and obstructive airways disease (OHAD). The aim of this study is to compare baseline sleep-related symptoms, health-related quality of life, and neurocognitive function between OHS and OHAD and the impact of PAP therapy on these outcomes. Methods: Epworth Sleepiness Scale (ESS), Pittsburgh Sleepiness Quality Index (PSQI), SF36, and various neurocognitive tests, in addition to anthropometric, polysomnography, lung function, and blood gas data from participants with OHS and participants with OHAD, were included in the analysis. These data were originally collected in their respective randomized clinical trials, comparing the efficacy of different PAP modes (bilevel PAP vs. CPAP) in resolving hypercapnia. Between groups (OHS vs OHAD), pre- and post-treatment (with 3 months of positive airway pressure) comparisons were made using linear mixed modeling. Results: 45 OHS participants (mean age 51 years old, 33% female, BMI 52 kg/m2, FER 0.81, PaCO2 54 mmHg, AHI 87/h) and 32 OHAD participants (mean age 61years old, 31% female, BMI 43kg/m2, FER 0.60, PaCO2 54 mmHg, AHI 59/h) were included in the analysis. Both OHS and OHAD had similar baseline ESS (14(5.6) vs. 12(5.4)), Global PSQI (10(3.2) vs. 11(4.8)), SF36 and neurocognitive test performances (other than OHAD had lower digit symbol substitution test performance). Treatment with PAP therapy resulted in similar ESS, Global PSQI, and SF36 improvements in both groups. Neurocognitive performance did not significantly improve after PAP therapy in either group. Conclusions: The symptom impact between two separate hypoventilation disorders (OHS and OHAD), in terms of sleepiness, sleep quality, quality of life, and cognitive function, were similar. OHS and OHAD had similar treatment responses in these parameters after 3 months of PAP therapy.Nocturnal ventilatory support in OHS.

Appropriate prescribing of azithromycin for community-acquired pneumonia.

Azithromycin is prescribed for atypical antimicrobial cover in severe community-acquired pneumonia. Inappropriate azithromycin administration incurs unnecessary financial costs, exacerbates antimicrobial resistance and risks QTc interval prolongation leading to cardiac arrhythmias. The present study demonstrated that a majority of patients were prescribed azithromycin without having electrocardiograms to assess the QTc interval and without meeting criteria for severe community-acquired pneumonia based on CURB-65 score.

A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease.

STUDY OBJECTIVES: Both obesity and airways disease can lead to chronic hypercapnic respiratory failure, which can be managed with positive airway pressure (PAP) therapy. The efficacy of PAP has been studied in obesity hypoventilation syndrome as well as in chronic hypercapnic chronic obstructive pulmonary disease patients, but not in patients where both obesity and airway obstruction coexist. This pilot study aims to compare the efficacy of continuous positive airway pressure vs bilevel positive airway pressure spontaneous mode in the treatment of hypoventilation disorder with obesity and obstructive airways disease. METHODS: We sequentially screened PAP-naïve patients with stable chronic hypercapnic respiratory failure (PaCO2 > 45 mm Hg), obesity (body mass index > 30 kg/m2), and obstructive airways disease. Participants were randomized to continuous positive airway pressure or bilevel positive airway pressure spontaneous mode treatment for 3 months. Participants were blinded to their PAP allocation. Change in awake PaCO2 was the primary endpoint. Secondary endpoints included change in lung function, daytime sleepiness, sleep quality, quality of life, PAP adherence, and neurocognitive function. RESULTS: A total of 32 individuals were randomized (mean ± SD: age 61 ± 11 years, body mass index 43 ± 7 kg/m2, PaCO2 54 ± 7 mm Hg, forced expiratory volume in 1 second 1.4 ± 0.6L, apnea-hypopnea index 59 ± 35 events/h). Sixteen participants in each PAP group were analyzed. Bilevel positive airway pressure yielded a greater improvement in PaCO2 compared to continuous positive airway pressure (9.4 mm Hg, 95% confidence interval, 4.3-15 mm Hg). There were no significant differences in PAP adherence, sleepiness, sleep quality, or neurocognitive function between the two therapies. CONCLUSIONS: Although both PAP modalities improved hypercapnic respiratory failure in this group of individuals, bilevel positive airway pressure spontaneous mode showed greater efficacy in reducing PaCO2. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Name: Nocturnal ventilatory support in obesity hypoventilation syndrome; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12605000096651; Identifier: ACTRN12605000096651. CITATION: Zheng Y, Yee BJ, Wong K, Grunstein R, Piper A. A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease. J Clin Sleep Med. 2022;18(1):99-107.

Cardiovascular disease in obesity hypoventilation syndrome - A review of potential mechanisms and effects of therapy.

Cardiovascular disease is common in patients with obesity hypoventilation syndrome (OHS) and accounts in part for their poor prognosis. This narrative review article examines the epidemiology of cardiovascular disease in obesity hypoventilation syndrome, explores possible contributing factors and the effects of therapy. All studies that included cardiovascular outcomes and biomarkers were included. Overall, there is a higher burden of cardiovascular disease and cardiovascular risk factors among patients with obesity hypoventilation syndrome. In addition to obesity and sleep-disordered breathing, there are several other pathophysiological mechanisms that contribute to higher cardiovascular morbidity and mortality in OHS. There is evidence emerging that positive airway pressure therapy and weight loss have beneficial effects on the cardiovascular system in obesity hypoventilation syndrome patients, but further research is needed to clarify whether this translates to clinically important outcomes.

A feasibility study of a mobile app to treat insomnia.

Insomnia is a major public health concern. Sleep restriction therapy (SRT) is an effective behavioral treatment but its delivery is impeded by a shortage of trained clinicians. We developed a mobile app delivering SRT to individuals with insomnia. This feasibility study employed a mixed-methods design to examine the engagement, acceptability, and potential efficacy of the mobile app. Fifteen participants diagnosed with insomnia disorder used the mobile app synchronized with a wearable device for 3 weeks. Those who persisted with the study (n = 12) found the mobile app to be highly acceptable and engaging, logging on average 19 nightly sleep diary entries across the 21 day period. Significant improvements were observed for sleep measures (insomnia severity and sleep efficiency) and daytime symptoms (fatigue and sleepiness). The results suggest that a mobile app delivering SRT to individuals with insomnia is engaging, acceptable, and potentially efficacious. Further, a full-scale effectiveness study is warranted.

Inspiratory Muscle Training Improves Inspiratory Muscle Strength and Functional Exercise Capacity in Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension: A Pilot Randomised Controlled Study.

BACKGROUND: Exercise intolerance is present even in the early stages of pulmonary arterial hypertension (PAH) and is associated with poorer prognosis. Respiratory muscle dysfunction is common and may contribute to exercise limitation. We sought to investigate the effects of inspiratory muscle training (IMT) to improve exercise capacity in PAH. METHODS: Adults with PAH were prospectively recruited and randomly assigned to either IMT or a control group. At baseline and after 8 weeks, assessment of respiratory muscle function, pulmonary function, neurohormonal activation, 6-minute walk distance and cardiopulmonary exercise testing variables were conducted. Inspiratory muscle strength was assessed by maximal static inspiratory pressure (PImax). The IMT group performed two cycles of 30 breaths at 30-40% of their PImax 5 days a week for 8 weeks. RESULTS: Twelve (12) PAH patients (60±14 years, 10 females) were recruited and randomised (six in the IMT group and six in the control group). After 8 weeks, the IMT group improved PImax by 31 cmH2O compared with 10 cmH2O in controls, p=0.02. Following IMT, 6-minute walk distance improved by 24.5 m in the IMT group and declined by 12 m in the controls (mean difference 36.5 m, 95% CI 3.5-69.5, p=0.03). There was no difference in peak oxygen uptake between-groups (mean difference 0.4 mL/kg/min, 95% CI -2.6 to 3.4, p=0.77). There was no difference in the mean change between-groups in neurohormonal activation or pulmonary function. CONCLUSION: In this pilot randomised controlled study, IMT improved PImax and 6-minute walk distance in PAH patients.