Appropriate BMI Criteria for Indian Population: Does It Help Stratify Obstructive Sleep Apnea (OSA) Patients Better?

Abstract

Obstructive sleep apnea (OSA) is a common yet unrecognized medical problem with significant morbidity. It is commonly considered an obesity-related problem, although not uncommon in non-obese patients of Indian origin. Currently, the World Health Organization (WHO) Western BMI criteria are widely used to classify obesity levels. Indian population has a different association between body mass index (BMI), percentage of body fat, and health risks compared to the western population. Due to these ethnic variations, applying the appropriate criteria—the WHO recommendation for appropriate BMI for Asian population—would be more suitable for identifying obesity in Indians, and, hence, to identify those at risk for OSA. We aimed to explore the discrepancy that could arise by applying the WHO Western BMI criteria to the Indian population which might misclassify and exclude those who are at risk for obesity-related OSA. This is a retrospective study of patients who presented to Nithra Institute of sleep sciences, Chennai, India, from May 2015 to May 2017. Patients who underwent polysomnography and diagnosed with OSA were included. Data pertaining to demographics, BMI, and severity of OSA were collected and analyzed. Patients were classified into different weight bands based on both the Western and Asian BMI criteria and compared. Stratification based on severity of OSA and its association with both the BMI classification was also analyzed. During the study period, 904 patients were clinically suspected to have OSA, of whom 787 patients underwent polysomnography. Of these, 754 patients were confirmed to have OSA and were included in the study. [626 males (83%)/128 females (16.9%); mean age—50.7 ± 28.6 years]. 735 (97.5%) patients were classified as overweight/obese as per Asian BMI, whereas only 695 (92.2%) patients were classified as overweight/obese as per Western BMI classification. With respect to the association of the BMI categories with the severity of OSA, there were significant differences between the numbers of severe OSA patients in each weight band of Asian BMI when compared to Western BMI. OSA may be underestimated clinically in Indian population when Western BMI criteria is applied. Asian BMI as recommended by WHO is more suitable in reflecting the correlation between obesity and OSA than the western BMI criteria.