[Obstructive sleep apnea and metabolic syndrome: an association study based on a large sample clinical database]

Objective: To investigate the prevalence and associated risk factors of metabolic syndrome (MS) in patients with obstructive sleep apnea (OSA). Methods: From July 2007 to June 2017, a total of 8 155 adult subjects, including 6 484 males and 1 671 females, aged 18-90 (43.13±12.28), body mass index 14.61~59.56 (25.59±3.98) kg/m²,who were admitted to the Department of Otorhinolaryngology head and Neck surgery of The Sixth People's Hospital affiliated to Shanghai Jiao Tong University, were retrospectively analyzed. All patients underwent polysomnography and biochemical tests. Subjects were divided into four groups (non-OSA, mild OSA, moderate OSA, and severe OSA) according to OSA severity. The prevalence of MS was expressed as percentage, and the correlation between OSA and MS and its characteristic pathophysiological indicators was evaluated by logistic regression model after adjusting for factors such as gender, age, BMI, neck circumference, hip circumference, smoking and alcohol consumption, and was expressed by odds ratio (OR). SPSS 25.0 software was used for statistical analysis. Results: The overall prevalence of MS was 43.6%, and that of non-/mild/moderate/severe OSA group was 18.6%, 30.4%, 43.8%, 57.1%.Logistic regression showed that patients with mild/moderate/severe OSA had an increased risk of MS compared with non-OSA patients, with adjusted OR values and confidence intervals of 1.27 (1.05-1.54), 1.84 (1.53-2.22), and 2.08 (1.76-2.46), respectively (P<0.01).In addition, indicators of OSA anoxic burden [oxygen drop index(T_oxygen=7.1), minimum blood oxygen(T_minimum=56.3), blood oxygen saturation below 90% cumulative time ratio (T_CT90=10.6) ]were closely associated with MS disease(P<0.01), but sleep fragmentation index (arousals index) was not significantly associated with MS disease. Conclusion: The risk of MS gradually increases with the severity of OSA, and the indicators reflecting OSA hypoxia burden are closely related to MS disease.