Clinical utility of limited channel sleep studies versus polysomnography for obstructive sleep apnoea.

BACKGROUND

Obstructive sleep apnoea (OSA) is a common cause of sleep disturbance, characterised by the presence of repetitive upper airway obstruction during sleep. OSA is associated with sleepiness during the day, reduced quality of life and an increased risk of cardiovascular disease. OSA can be diagnosed using several different strategies. The current reference test is fully supervised polysomnography, which is expensive and time-consuming. Other diagnostic tests, referred to as limited channel sleep studies because they include fewer parameters than polysomnography, are less resource-intensive but may also have different diagnostic performances, resulting in a difference in clinical outcomes.

OBJECTIVES

To assess the clinical impact (outcome on a participant level) of a strategy where treatment follows diagnostic testing (test-treatment combination) using limited channel sleep studies compared to polysomnography in people with suspected obstructive sleep apnoea (OSA).

SEARCH METHODS

We searched two databases (CENTRAL, MEDLINE) up to 11 May 2023 using search terms related to OSA and polysomnography developed by our information specialist.

SELECTION CRITERIA

We included randomised controlled trials that compared any limited channel sleep studies with Level I fully supervised polysomnography in adults (aged 18 years and older) with suspected OSA. Our primary outcome was sleepiness, and our secondary outcomes were quality of life, all-cause mortality, cardiovascular events and correlating risk factors, continuous positive airway pressure (CPAP) usage, serious adverse events, and cost-effectiveness.

DATA COLLECTION AND ANALYSIS

Four review authors extracted data from the included trials and assessed the risk of bias. We summarised treatment effects using random-effects meta-analyses and expressed as mean difference (MD) or standardised mean difference (SMD) with corresponding 95% confidence intervals (CI) where possible. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included three trials with 1143 participants. One trial compared Level III sleep studies to a Level I fully supervised polysomnography, one trial compared Level IV sleep studies to Level I sleep studies, and one trial compared Level IV sleep studies versus Level III sleep studies versus Level I sleep studies. The follow-up of these trials ranged from four to six months. Level III sleep studies versus Level I sleep studies There is high-certainty evidence that Level III sleep studies result in little to no difference in sleepiness (MD 0.47, 95% CI -0.23 to 1.18; P = 0.19, I = 0%; 2 trials, 701 participants) or quality of life (SMD 0.01, 95% CI -0.14 to 0.16; P = 0.93, I = 0%; 2 trials, 701 participants) compared to Level I sleep studies. Level III sleep studies are also probably slightly more cost-effective (moderate-certainty evidence). There is low-certainty evidence that they may result in little to no difference in cardiovascular events and correlating risk factors, CPAP adherence (MD -0.18 hours per day, 95% CI -0.56 to 0.20; P = 0.36, I = 0%; 2 trials, 360 participants) or serious adverse events. Level IV sleep studies versus Level I sleep studies There is low-certainty evidence that Level IV sleep studies may not increase sleepiness compared to Level I sleep studies (MD 0.66, 95% CI -0.41 to 1.72; P = 0.23, I = 39%; 2 trials, 573 participants). Additionally, there is low-certainty evidence that they may result in little to no difference in cardiovascular events and correlating risk factors. For quality of life, CPAP adherence, serious adverse events and cost-effectiveness, the evidence is very uncertain. None of the included trials reported on all-cause mortality.

AUTHORS' CONCLUSIONS: Level III sleep studies may result in little to no difference in clinical outcomes when compared to Level 1 sleep studies in people with suspected OSA. Level IV sleep studies may not increase sleepiness and may result in little to no difference in cardiovascular events and correlating risk factors compared to Level I sleep studies; the evidence was too uncertain to make statements for other outcomes. Overall, the body of evidence was limited, therefore more trials making this comparison are necessary, as are trials with a longer follow-up duration.