Non-invasive ventilation in obesity hypoventilation syndrome without severe obstructive sleep apnoea

Abstract

BackgroundNon-invasive ventilation (NIV) is an effective form of treatment in patients with obesity hypoventilation syndrome (OHS) who have concomitant severe obstructive sleep apnoea (OSA). However, there is a paucity of evidence on the efficacy of NIV in patients with OHS without severe OSA. We performed a multicentre randomised clinical trial to determine the comparative efficacy of NIV versus lifestyle modification (control group) using daytime arterial carbon dioxide tension (PaCO2) as the main outcome measure.MethodsBetween May 2009 and December 2014 we sequentially screened patients with OHS without severe OSA. Participants were randomised to NIV versus lifestyle modification and were followed for 2 months. Arterial blood gas parameters, clinical symptoms, health-related quality of life assessments, polysomnography, spirometry, 6-min walk distance test, blood pressure measurements and healthcare resource utilisation were evaluated. Statistical analysis was performed using intention-to-treat analysis.ResultsA total of 365 patients were screened of whom 58 were excluded. Severe OSA was present in 221 and the remaining 86 patients without severe OSA were randomised. NIV led to a significantly larger improvement in PaCO2 of −6 (95% CI −7.7 to −4.2) mm Hg versus −2.8 (95% CI −4.3 to −1.3) mm Hg, (p<0.001) and serum bicarbonate of −3.4 (95% CI −4.5 to −2.3) versus −1 (95% CI −1.7 to −0.2 95% CI) mmol/L (p<0.001). PaCO2 change adjusted for NIV compliance did not further improve the inter-group statistical significance. Sleepiness, some health-related quality of life assessments and polysomnographic parameters improved significantly more with NIV than with lifestyle modification. Additionally, there was a tendency towards lower healthcare resource utilisation in the NIV group.ConclusionsNIV is more effective than lifestyle modification in improving daytime PaCO2, sleepiness and polysomnographic parameters. Long-term prospective studies are necessary to determine whether NIV reduces healthcare resource utilisation, cardiovascular events and mortality.Trial registration numberNCT01405976; results.

Non‐invasive ventilation for obese patients with chronic respiratory failure: Are two pressures always better than one?

“…Initial studies used an apnoea–hypopnoea index (AHI) of 5 events /h, indicating a ‘normal’ level of apnoea, but more recently, this has been increased to 30 events/h, indicating ‘severe’ OSA. This change in cut‐off point alters the proportion of patients in this phenotypic group from 5% to ~30% . The reason for the change is based on the evidence for therapy in eucapnic OSA.…”

“…predominant isolated hypoventilation phenotype), there are limited data to support the clinical utility of CPAP therapy, and routine practice is to offer NIV to patients in this group with evidence of any of the following features: symptoms of sleep disruption or daytime hypersomnia, a history of acute decompensated respiratory failure, significant respiratory failure or presence of severe co‐morbidities such as heart failure. There are case series demonstrating short‐term stability and a randomized controlled trial demonstrating an improvement in respiratory failure with NIV compared to lifestyle advice alone in selected patients with OHS without severe OSA . Whether CPAP has an acceptable therapeutic effect in patients with mild–moderate OSA but predominant hypoventilation is unclear.…”

“…This change in cut-off point alters the proportion of patients in this phenotypic group from 5% to~30%. 38 The reason for the change is based on the evidence for therapy in eucapnic OSA. The data support treatment with CPAP therapy for those symptomatic patients with severe OSA, and few clinicians would be comfortable with withholding therapy, making the original classification difficult to implement in a randomized controlled trial.…”

CPAP or non-invasive ventilation in obesity hypoventilation syndrome: does it matter which one you start with?

“…In these patients, CPAP may not be effective. Although NIV has been shown to be superior to lifestyle changes in patients with OHS without severe OSA,16 to our knowledge there is no randomised trial comparing CPAP with bilevel PAP in this particular phenotype of OHS. While data from several observational studies suggest that long-term NIV is associated with better survival rates,8 the Pickwick study by the Spanish Sleep Network—the largest trial of OHS with 36 months of follow-up—will shed further light on whether long-term NIV is more effective than CPAP therapy 12 17…”

NIV for OHS without severe OSAS: is it worth it?

“…Masa et al 9 present data in this edition of Thorax on treatment responses in this group of chronic obesity-related respiratory failure without severe OSA. The paper provides much information to guide and inform the clinicians in this area.…”