Article Text

Download PDFPDF
Original article
A randomised controlled trial of CPAP versus non-invasive ventilation for initial treatment of obesity hypoventilation syndrome
  1. Mark E Howard1,2,3,4,
  2. Amanda J Piper5,
  3. Bronwyn Stevens1,2,
  4. Anne E Holland1,6,7,
  5. Brendon J Yee5,
  6. Eli Dabscheck4,6,
  7. Duncan Mortimer4,
  8. Angela T Burge6,
  9. Daniel Flunt5,
  10. Catherine Buchan6,
  11. Linda Rautela1,2,
  12. Nicole Sheers1,2,
  13. David Hillman8,
  14. David J Berlowitz1,2,3
  1. 1Institute for Breathing and Sleep, Heidelberg, Australia
  2. 2Austin Health, Heidelberg, Australia
  3. 3University of Melbourne, Parkville, Australia
  4. 4Monash University, Clayton, Australia
  5. 5Royal Prince Alfred Hospital, Camperdown, Australia
  6. 6Alfred Health, Melbourne, Australia
  7. 7La Trobe University, Melbourne, Australia
  8. 8Sir Charles Gairdner Hospital, Nedlands, Australia
  1. Correspondence to Dr Mark E Howard, Bowen Centre, Austin Hospital, Heidelberg, VIC 3084, Australia. mark.howard{at}


Background Obesity hypoventilation syndrome (OHS) is the most common indication for home ventilation, although the optimal therapy remains unclear, particularly for severe disease. We compared Bi-level and continuous positive airways pressure (Bi-level positive airway pressure (PAP); CPAP) for treatment of severe OHS.

Methods We conducted a multicentre, parallel, double-blind trial for initial treatment of OHS, with participants randomised to nocturnal Bi-level PAP or CPAP for 3 months. The primary outcome was frequency of treatment failure (hospital admission, persistent ventilatory failure or non-adherence); secondary outcomes included health-related quality of life (HRQoL) and sleepiness.

Results Sixty participants were randomised; 57 completed follow-up and were included in analysis (mean age 53 years, body mass index 55 kg/m2, PaCO2 60 mm Hg). There was no difference in treatment failure between groups (Bi-level PAP, 14.8% vs CPAP, 13.3%, p=0.87). Treatment adherence and wake PaCO2 were similar after 3 months (5.3 hours/night Bi-level PAP, 5.0 hours/night CPAP, p=0.62; PaCO2 44.2 and 45.9 mm Hg, respectively, p=0.60). Between-group differences in improvement in sleepiness (Epworth Sleepiness Scale 0.3 (95% CI -2.8, 3.4), p=0.86) and HRQoL (Short Form (SF)36-SF6d 0.025 (95% CI -0.039, 0.088), p=0.45) were not significant. Baseline severity of ventilatory failure (PaCO2) was the only significant predictor of persistent ventilatory failure at 3 months (OR 2.3, p=0.03).

Conclusions In newly diagnosed severe OHS, Bi-level PAP and CPAP resulted in similar improvements in ventilatory failure, HRQoL and adherence. Baseline PaCO2 predicted persistent ventilatory failure on treatment. Long-term studies are required to determine whether these treatments have different cost-effectiveness or impact on mortality.

Trial registration number ACTRN12611000874910, results.

  • Non invasive ventilation
  • Sleep apnoea

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Australian trial finds that CPAP provides similar benefits to non-invasive ventilation in severe obesity hypoventilation syndrome.

  • Contributors MEH co-developed and drafted the protocol, conducted statistical analysis, recruited participants, drafted the manuscript and generated figures; DJB co-developed and drafted the protocol, wrote the institutional review board application, co-developed analysis, generated the random allocation sequence, assigned participants and edited the manuscript; AJP co-developed and drafted the protocol, co-developed analysis, recruited participants and edited the manuscript; AEH and BJY co-developed the protocol, recruited participants, co-developed analysis and edited the manuscript; DH co-developed the protocol and analysis and edited the manuscript. BS contributed to design, recruited participants, collected and entered data, conducted analysis and edited the manuscript; ED, DM, ATB, DF, CB, LR and NS contributed to design, recruited participants, collected and entered data and edited the manuscript.

  • Funding This investigator-initiated project was funded by an unrestricted grant from the ResMed Foundation, San Diego, California, USA.

  • Competing interests MEH reports grants from ResMed Foundation, during the conduct of the study; non-financial support from Philips Respironics, outside the submitted work. AJP reports grants from ResMed Foundation, personal fees from ResMed, personal fees from Philips Respironics, during the conduct of the study; personal fees from SenTec, outside the submitted work. DM reports grants from ResMed Foundation, during the conduct of the study; grants from National Health and Medical Research Council, grants from Victoria Neurotrauma Initiative, outside the submitted work. BS, AEH, BJY, ED, ATB, DF, CB, LR, NS, DH and DJB report a grant from ResMed Foundation, during the conduct of the study.

  • Ethics approval Austin Health Human Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Linked Articles