Apnoea–hypopnoea indices determined via continuous positive airway pressure (AHI-CPAP(flow)) versus those determined by polysomnography (AHI-PSG(gold)): a protocol for a systematic review and meta-analysis

INTRODUCTION: To date, continuous positive airway pressure (CPAP) remains the cornerstone of obstructive sleep apnoea treatment. CPAP data describing residual sleep-disordered breathing events (ie, the CPAP-measured apnoea–hypopnoea indices (AHI-CPAP(flow))) is difficult to interpret because it is an entirely different metric than the polysomnography (PSG) measured AHI gold standard (AHI-PSG(gold)). Moreover, manufacturer definitions for apnoea and hypopnoea are not only different from those recommended for PSG scoring, but also different between manufacturers. In the context of CPAP initiation and widespread telemedicine at home to facilitate sleep apnoea care, there is a need for concrete evidence that AHI-CPAP(flow) can be used as a surrogate for AHI-PSG(gold). METHODS AND ANALYSIS: No published systematic review and meta-analysis (SRMA) has compared the accuracy of AHI-CPAP(flow) against AHI-PSG(gold) and the primary objective of this study is therefore to do so using published data. The secondary objectives are to similarly evaluate other sleep disordered breathing indices and to perform subgroup analyses focusing on the inclusion/exclusion of central apnoea patients, body mass index levels, CPAP device brands, pressure titration modes, use of a predetermined and fixed pressure level or not, and the impact of a 4% PSG desaturation criteria versus 3% PSG on accuracy. The Preferred Reporting Items for SRMA protocols statement guided study design. Randomised controlled trials and observational studies of adult patients (≥18 years old) treated by a CPAP device will be included. The CPAP intervention and PSG comparator must be performed synchronously. PSGs must be scored manually and follow the American Academy of Sleep Medicine guidelines (2007 AASM criteria or more recent). To assess the risk of bias in each study, the Quality Assessment of Diagnostic Accuracy Studies 2 tool will be used. ETHICS AND DISSEMINATION: This protocol received ethics committee approval on 16 July 2020 (IRB_MTP_2020_07_2020000404) and results will be disseminated via peer-reviewed publications. PROSPERO/TRIAL REGISTRATION NUMBERS: CRD42020159914/NCT04526366; Pre-results