Characteristics of patients with positional OSA according to ethnicity and the identification of a novel phenotype – Lateral Positional Patients (Lateral PP): A MESA study

Study Objectives To investigate the characteristics of Obstructive Sleep Apnea (OSA) positional patients’ (PP) phenotypes among different ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA) dataset. Moreover, we hypothesized the existence of a new OSA PP phenotype we coined “Lateral PP”, for whom the lateral apneas hypopnea index (AHI) is at least double the supine AHI. Methods From 2,273 adults with sleep information, we analyzed data of 1,323 subjects that slept more than 4 hours and had at least 30 minutes of sleep in both the supine and the non-supine positions. Demographics and clinical information were compared for the different PP, and ethnic groups. Results 861 (65.1%) patients had OSA and 35 (4.1%) were Lateral PP. Lateral PP patients were mainly females (62.9%), obese (31.4 median body mass index), had mild to moderate OSA (94.3%), and mostly were non-Chinese American (97.1%). Among all OSA patients, 550 (63.9%) were Supine PP, and 17.7% were supine-isolated OSA (siOSA). Supine PP and Lateral PP were present in 73.1% and 1.0% of Chinese Americans, 61.0% and 3.4% of Hispanics, 68.3% and 4.7% of White-Caucasian, and 56.2% and 5.2% of Black-African American OSA patients. Conclusion Chinese-American have the highest prevalence of Supine PP, whereas Black-African American patients lean towards less Supine PP and higher Lateral PP. Lateral PP appears as a novel OSA phenotype. However, it was found for a small group of OSA patients and thus its presence should be further validated. Brief Summary We studied prevalence of obstructive sleep apnea (OSA) positional phenotypes among Black African-American, Caucasian, Hispanic, and Chinese American patients and described their demographic and polysomnographic characteristics. Despite similar levels of OSA severity in the four ethnic groups, Chinese American had a higher prevalence of Supine PP, whereas Black-African American patients were significantly less Supine PP, as compared to other ethnic groups. In addition, we identify a novel OSA PP phenotype we named “Lateral positional patients (Lateral-PP)”. These OSA patients had apnea and hypopnea events mainly in the lateral position. This was a small group of OSA patients (4.1%) that were mainly obese, female, with mild-moderate OSA, and more prevalent in Black-African American.