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Effects of suboptimal use of CPAP therapy on symptoms of obstructive sleep apnoea

English title Effects of suboptimal use of CPAP therapy on symptoms of obstructive sleep apnoea
Applicant Kohler Malcolm
Number 162534
Funding scheme Project funding
Research institution Klinik für Pneumologie Bereich Herz-Gefäss-Thorax Universitätsspital Zürich
Institution of higher education University of Zurich - ZH
Main discipline Internal Medicine
Start/End 01.01.2016 - 31.12.2018
Approved amount 412'101.00
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All Disciplines (2)

Internal Medicine
Clinical Pathophysiology

Keywords (3)

Continuous positive airway pressure; Adherence; Sleep Apnea

Lay Summary (German)

Hat ein suboptimaler Gebrauch der Überdruckbeatmung einen positiven Effekt auf die Symptomatik bei Patienten mit obstruktiver Schlafapnoe?
Lay summary

Obstruktive Schlafapnoe ist charakterisiert durch einen repetitiven Kollaps des Schlundes während des Schlafes, was zu Atmungsunterbrüchen, Blutsauerstoffabfällen und verminderter Schlafqualität führt. Die negativen Auswirkungen beinhalten eine erhöhte Schläfrigkeit, erhöhtes Unfallrisiko, und Herzkreislauferkrankungen.


Die effektivste Therapie für die obstruktive Schlafapnoe ist die kontinuierliche Überdruckbeatmung (CPAP, continuous positive airway pressure).  Die CPAP Therapie führt bewiesenermassen zu einer Verbesserung der Schläfrigkeit und des Bluthochdruckes bei Patienten mit symptomatischer obstruktiver Schlafapnoe, allerdings ist der Effekt abhängig von der Anzahl Gebrauchsstunden. Es wird allgemein von Ärzten angenommen, dass die CPAP Therapie während mindestens 4 Stunden pro Nacht angewendet werden muss, um einen positiven Effekt zu erzielen. 30-80% aller Patienten wenden die Therapie aber weniger als 4 Stunden pro Nacht an. Es fehlen zudem Daten von Studien, die belegen, dass 4 Stunden Therapie pro Nacht tatsächlich nötig sind, um einen positiven Effekt zu erzielen.


Es ist deshalb das Ziel des Projektes zu untersuchen, welchen Effekt ein CPAP Therapieentzug hat auf die Schläfrigkeit bei Patienten mit weniger als 4 Stunden CPAP-Gebrauch pro Nacht.


Zuerst wird der Effekt eines 2-wöchigen Therapieentzuges bei Patienten mit einer nächtlichen Nutzung der CPAP Therapie von 3-4 Stunden untersucht. Sollte es bei diesen Patienten unter Therapieentzug zu einem Auftreten von Schläfrigkeit kommen, werden in einem zweiten Schritt die Effekte des Therapieentzuges bei Patienten mit einem durchschnittlichen CPAP Gebrauch von 2-3 Stunden pro Nacht überprüft. Sollte es trotz 2-wöchigem Therapieentzug nicht zu einem Auftreten von Symptomen kommen, wird die Therapie für 4 Wochen entzogen.


Die Resultate dieser Studien helfen zu klären, ob es Sinn macht, dass solche Patienten weiterhin die verschriebene CPAP Therapie gebrauchen.  




Direct link to Lay Summary Last update: 25.11.2015

Responsible applicant and co-applicants



Effects of suboptimal adherence of CPAP therapy on symptoms of obstructive sleep apnoea: a randomised, double-blind, controlled trial
Gaisl Thomas, Rejmer Protazy, Thiel Sira, Haile Sarah R., Osswald Martin, Roos Malgorzata, Bloch Konrad E., Stradling John R., Kohler Malcolm (2020), Effects of suboptimal adherence of CPAP therapy on symptoms of obstructive sleep apnoea: a randomised, double-blind, controlled trial, in European Respiratory Journal, 55(3), 1901526-1901526.
Effects of CPAP and Mandibular Advancement Devices on Health-Related Quality of Life in OSA
Kuhn Eric, Schwarz Esther I., Bratton Daniel J., Rossi Valentina A., Kohler Malcolm (2017), Effects of CPAP and Mandibular Advancement Devices on Health-Related Quality of Life in OSA, in Chest, 151(4), 786-794.


Group / person Country
Types of collaboration
Prof. K.E. Bloch, Universitätsspital Zürich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. J.R. Stradling, Oxford University Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
172980 Acetazolamide for prevention of altitude related illness in patients with chronic obstructive pulmonary disease (COPD). Randomized, placebo-controlled, double-blind trial. 01.05.2017 Project funding
124915 Continuous positive airway pressure therapy withdrawal - a model to evaluate treatment modalities for sleep apnoea 01.05.2009 Project funding
143365 Mechanisms of vascular damage in obstructive sleep apnoea 01.01.2013 Project funding


Obstructive sleep apnoea (OSA) is characterised by a repetitive collapse of the pharynx during sleep, which results in apnoea or hypopnoea associated with oxygen desaturations and arousals from sleep. OSA affects up to 1 in 5 adults and is associated with daytime sleepiness and increased risk of traffic accidents, arterial hypertension, vascular dysfunction and cardiovascular events. The usual and most effective treatment for OSA is continuous positive airway pressure (CPAP). CPAP therapy has been shown to significantly reduce subjective sleepiness and blood pressure in patients with symptomatic OSA, however, its effectiveness tends to depend on its nightly usage. A commonly held view is that CPAP should be used for at least 4h/night in order to improve symptoms and cardiovascular outcomes, however, previous studies have estimated that a considerable proportion of CPAP users (29 to 83%) fail to achieve this. In addition, there is inadequate evidence to support this apparent threshold effect and so it is unclear whether such patients actually benefit from treatment or whether they could be withdrawn from CPAP, thus substantially reducing health care costs, or encouraged to increase their nightly usage of CPAP. The aim of the proposed project is to perform a series of randomised control trials to study the effect of CPAP withdrawal on subjective sleepiness in OSA patients using CPAP for less than 4h/night on average. CPAP therapy withdrawal is a proven model to efficiently investigate the effects of treatment on physiology, symptoms and cardiovascular risk in OSA. This model uses subjects from large cohorts of patients who are already being treated with CPAP and are registered in a database. Therefore, an adequate number of patients who have a particular nightly CPAP usage over the past several years can be recruited within a relatively short time. We will first investigate the effect of CPAP withdrawal in patients averaging 3-4h/night of CPAP usage. If withdrawal is shown to lead to a return of symptoms we will then perform a similar trial in patients using CPAP 2-3h/night, otherwise the more long-term effects of withdrawal will be investigated in the population of interest in the initial trial. The proposed RCTs will be the first randomised comparisons of suboptimal CPAP use versus a placebo therapy and will establish the consequences of withdrawing therapy in low users of CPAP. The results of the study will help to determine whether it is beneficial for such patients to remain on CPAP therapy or whether further encouragement is needed to increase CPAP usage and thus increase the benefit from treatment.