Metabolic Syndrome in Adults with Polysomnography-Confirmed Obstructive Sleep Apnoea: A Systematic Review and...

Obstructive sleep apnoea (OSA) and metabolic syndrome (MetS) are prevalent cardio-metabolic conditions which frequently coexist. Growing evidence indicates a positive association between OSA and MetS, but up-to-date global data are lacking, leaving the true strength of the association uncertain. Therefore, this systematic review and meta-analysis aimed to provide an updated and comprehensive synthesis of evidence on the risk of MetS in adults with polysomnography (PSG)-confirmed OSA.

A systematic review and three-level random-effects meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Searches were performed of the Ovid MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane and Embase databases, yielding 8072 records. Studies reporting either odds ratios (OR) for MetS in adults with PSG-confirmed OSA compared to those without OSA, or with data to calculate these, were eligible for inclusion. Risk of bias was assessed using the RoBANS (Risk of Bias Assessment tool for Non-randomised Studies) tool. Subgroup analyses and meta-regression were performed to explore sources of heterogeneity.

A total of 68 studies from 24 countries with 74 relevant effect sizes were included (24,663 adults with PSG-confirmed OSA; 11,423 without OSA). Adults with OSA had over threefold higher odds of MetS compared with those without (odds ratio 3.33, 95% confidence interval 2.86-3.87; p < 0.0001). Substantial heterogeneity was noted (I² = 73.8%). Study design, geographic region, MetS definition/criteria, Apnoea-Hypopnea Index OSA diagnostic threshold and publication year significantly moderated the pooled estimate (all p < 0.05). A larger body mass index difference between groups was associated with higher odds of MetS (β = 0.14, t = 4.03, p < 0.001), whereas a higher proportion of male participants was associated with lower odds of MetS (β = - 0.01, t = - 2.81, p < 0.010).

Adults with PSG-confirmed OSA have over threefold higher odds of having MetS, consistently across diverse populations. Thus, early and routine metabolic screening is recommended for all adults with OSA. Future research should incorporate longitudinal and genetic data to explore causal links between OSA and MetS.

CRD420251073055.