Abstract:Objective To investigate the correlation of body mass index (BMI) with the severity of obstructive sleep apnea hypopnea syndrome (OSAHS) in the elderly. Methods The medical records of 609 elderly patients (≥60 years old) suffering from OSAHS diagnosed by standard polysomnography in Chinese PLA General Hospital, Peking University International Hospital and the Affiliated Hospital of Gansu University of Traditional Chinese Medicine from January 2015 to October 2017 were collected and analyzed retrospectively. The subjects were divided into the normal weight (n=154), overweight (n=228) and obese (n=227) groups according to their different levels of BMI. The main indicators of polysomnography were compared among the three groups. SPSS statistics 25.0 was used for data analysis. Spearman rank correlation analysis was used to study the correlation between BMI and these main indicators, and multivariate logistic regression analysis was applied to explore the correlation between different BMI levels and OSAHS severity in the elderly. Results There were no significant differences in levels of apnea hypopnea index (AHI), time of oxygen saturation(SaO2)<90%, oxygen desaturation index (ODI) , mean pause time, lowest oxygen saturation, mean oxygen saturation and percentage of the times for SaO2 <90% in total monitoring time during overnight sleep (T90) among the 3 groups (P<0.05). BMI was positively correlated with AHI, maximum pause time, ODI, T90 and time of SpO2<90% (r=0.294,0.113,0.313,0.413,0.411, all P<0.05), but negatively correlated with mean oxygen saturation and minimum oxygen saturation in the elderly OSAHS patients (r=-0.173, -0.229, all P<0.05). The risk of severe OSAHS in the overweight group was 1.690 times higher than that of the normal weight group (OR=1.690), and the risk was even higher in the obese group (OR=3.685). A stratified analysis between the hypertension and non-hypertension subjects found that the correlation between obesity and severe OSAHS existed in both hypertensive and non-hypertensive subgroups, and the correlation between obesity and severe OSAHS was greater in non-hypertensive subjects. Conclusion In the elderly, the greater BMI is, the more severe OSAHS is. The correlation between BMI and severity of OSAHS is stronger for the non-hypertensive elderly people.