The Correlation of Physical Parameters and Apnea-Hypopnea Index in OSA Suspected Thai Patients

Abstract

Most Asian countries have limited resources for polysomnography. Risk factors for Obstructive Sleep Apnea (OSA) in Asian populations may be different from the Western countries. Knowing the physical risk factors for OSA may be a helpful tool for clinicians to select suitable patients to be tested for OSA. We enrolled consecutive OSAsuspected patients between October 1st, 2006 and September 30th, 2007. Physical factors including Body Mass Index (BMI), Neck Circumference (NC), and Waist Circumference (WC) were recorded. The correlations of BMI, NC, WC and Apnea-Hypopnea Index (AHI) were executed. Various cut points of BMI, NC, and WC were calculated for sensitivity and specificity of severity of OSA. During the study period, there were 66 patients enrolled. All three parameters (BMI, NC, and WC) were significantly correlated with AHI. The highest correlation index was between BMI and AHI (0.604), whereas the correlation index of AHI-WC and AHI-NC were 0.571 and 0.440, respectively. Only BMI and WC, but not NC, were significantly related to severity of OSA. The BMI of more than 25 kg/m2 had the highest sensitivity (93.8%) for severe OSA, whereas WC more than 101.8 cm had the highest specificity (92%). In conclusion, BMI, WC, and NC are correlated with AHI in OSA suspected Thai patients. BMI and WC, but not NC, were associated with severity of OSA. In resource-limited facilities, these parameters may be helpful for clinicians to evaluate the risk of OSA more appropriately.