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Long-term clinical effectiveness of continuous positive airway pressure therapy versus non-invasive ventilation therapy in patients with obesity hypoventilation syndrome: a multicentre, open-label, randomized controlled trial

Author(s): Masa JF et al

Lancet. 2019; 393(10182): 1721-1732

Sleep and breathing disorders
General respiratory patient care

Digest Author(s): Sophia Schiza, Chair of Group 4.02 / 30 April, 2019

This study is a nationwide, multicenter, open-label, randomized controlled trial, contacted between May 2009 to March 2013, included 204 untreated patients with Obesity Hypoventilation Syndrome (OHS) and severe Obstructive Sleep Apnoea (OSA), (AHI>30), who were in stable hypercapnic respiratory failure. Using simple randomization through an electronic database, 107 patients allocated to Continuous Positive Airway Pressure (CPAP) group and 97 in the Non-Invasive Ventilation (NIV) group, with a median follow-up 5.44 years.

Primary outcome was the number of hospitalization days per year for any cause and secondary outcomes were: emergency department visits, hospital and ICU admissions, incident cardiovascular events, all-cause mortality, blood pressure, arterial blood gases parameters, spirometry, 6-MWD, health related quality of life, BMI, dyspnoea classified using MRC scale and clinical symptoms related to OHS.

Additionally, in all follow-ups they evaluated adherence with treatment. They found that both interventions seem to have similar long-term effectiveness. The mean hospitalization days per patient year were 1.63 (SD 3.74) in the CPAP group and 1.44 (3.07) in the NIV group (adjusted rate ratio 0.78, p:0.561), adverse events were similar between groups. The most common cause of death was of cardiovascular origin, 56% for CPAP and 54% for NIV group. All secondary outcomes improved in both groups without statistical difference. Median adherence was 6h/day for both groups, 67% from CPAP group and 63% from NIV used their machines more than 4h/night.


This is the largest study with the longest period of follow-up in patients with OHS and severe OSA who were in stable hypercapnic respiratory failure. Both treatments showed similar long-term effectiveness concerning primary and secondary outcomes. Despite adequate adherence to both treatments, cardiovascular event rate remains clinically significant and highlights the importance of a holistic approach that additionally includes bodyweight reduction, increased level of activity and appropriate management of comorbidities. CPAP was less expensive and easier to implement than NIV, therefore taking into account cost effectiveness as well, might be preferable first line treatment in stable patients with OHS and severe OSA. However, NIV might have a superior effectiveness than CPAP in certain subgroups of patients like the ones with OHS and sleep hypoventilation alone, therefore a case-by-case assessment is recommended. Larger sample sizes, multicenter, multiethnic, age and gender matched studies will be required to verify the results as well as to show significant mortality differences between the two treatment modalities.