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. 2025 Nov 2.
doi: 10.1002/resp.70151. Online ahead of print.

A Pilot Randomised Non-Inferiority Trial of Auto-Titrating Versus Fixed Continuous Positive Airway Pressure for Obesity Hypoventilation Syndrome With Severe Obstructive Sleep Apnoea

Yizhong Zheng  1   2   3 , Amanda Piper  4 , Keith Wong  1   4   5 , Gislaine Gauthier  4   5 , Craig L Phillips  1   6 , Ronald Grunstein  1   4   5   6 , Brendon J Yee  1   4   5   6
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A Pilot Randomised Non-Inferiority Trial of Auto-Titrating Versus Fixed Continuous Positive Airway Pressure for Obesity Hypoventilation Syndrome With Severe Obstructive Sleep Apnoea

Yizhong Zheng et al. Respirology. .

Abstract

Background and objective: Fixed CPAP (fCPAP) is the preferred first-line ventilatory therapy in patients with obesity hypoventilation syndrome with severe obstructive sleep apnoea (OHS + sOSA). Auto-titrating CPAP (APAP) is not recommended but has not been systematically evaluated in this population. Our pilot study aimed to provide feasibility data for a larger comparative effectiveness trial to determine whether APAP is non-inferior to fCPAP for improving hypercapnic respiratory failure.

Methods: Participants with OHS + sOSA were randomised to either APAP or fCPAP for 3 months. The primary outcome was the change in PaCO2. Secondary outcomes included changes in quality of life and cardiovascular biomarkers. A sample size of 82 was needed to demonstrate non-inferiority of APAP compared to fCPAP (assuming a non-inferiority margin of -2.5 mmHg). To assess feasibility we aimed to recruit up to 44 participants in this pilot trial.

Results: Twenty-eight of 84 screened participants were randomised (Mean ± SD: Age 55 ± 12.5 years, BMI 54 ± 9.9 kg m-2, PaCO2 49 ± 2.6 mmHg, AHI 88 ± 31 events/h) to APAP (n = 15) or fCPAP (n = 13). Mean adherence exceeded 4 h in both groups; however 25% of randomised participants did not complete the trial. Both treatments reduced PaCO2 (fCPAP: -5.7 ± 1.6 mmHg, APAP: -4.1 ± 2.8 mmHg). Test of non-inferiority for APAP versus fCPAP was inconclusive (mean ΔPaCO2 difference = -1.7 mmHg (95% CI -5.0 to 1.6 mmHg)). Adherence and sleep quality improvements favoured fCPAP, while other outcomes were comparable.

Conclusion: The pilot study highlighted important challenges with recruitment and retention. While the study is not powered to confirm the non-inferiority of APAP, some outcomes appeared to favour fCPAP and APAP use in OHS + sOSA should be approached cautiously. A larger study with protocol modifications is required to confirm these preliminary findings.

Trial registration: ACTRN12618000379213. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374259. Assessing the Efficacy of Auto-titrating versus Fixed Continuous Positive Airway Pressure in Obesity Hypoventilation Syndrome.

Keywords: cardiovascular disease; hypercapnic respiratory failure; obesity; positive airway pressure therapy; quality of life; sleepiness.

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References

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