Oliveros H, Lobelo R, Giraldo-Cadavid LF, et al. - In this cohort-nested cross-sectional study, researchers sought to develop a severe obstructive sleep apnoea (OSA) prediction tool based on the clinical characteristics and anthropometric measurements of a clinical referral cohort living at 2640 m.a.s.l. From the 8,718 participants referred to the PSG laboratory, a predictive model was developed. The findings were later validated in the second cohort of 1,898 candidates. Body mass index (BMI), Age, Sex, Arterial hypertension and Neck circumference (BASAN) were the significant variables that were retained in the presence of severe OSA. The BASAN index, an objectively based approach to screening for the presence of severe OSA, has favorable sensitivity characteristics that should allow it to be used as a screening tool in a Hispanic population with a clinical suspicion of OSA and living at high altitude.