Clinical and Anthropometric Correlates of Polysomnography-Defined Severity in Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder frequently associated with cardiometabolic morbidity. In this retrospective study of 339 adults who underwent polysomnography (PSG) between January 2020 and December 2024, we investigated the relationship between routinely obtained clinical and anthropometric measures-body mass index (BMI), neck circumference (NC), waist circumference (WC), and the Epworth Sleepiness Scale (ESS)-and PSG-defined OSAS severity.

Adults (≥18 years) who underwent overnight PSG and had complete clinical and anthropometric data were included. OSAS severity was defined using the apnea-hypopnea index (AHI): no OSA (<5 events/h), mild (5-14.9), moderate (15-29.9), and severe (≥30). Associations between AHI and clinical or anthropometric measures were assessed using Spearman's correlation analysis.

A total of 339 patients were included (mean age 46.1±12.0 years; 73.2% male; mean BMI 33.2±6.2 kg/m²). The median ESS score was 4 (interquartile range [IQR]: 2-9), and the median AHI was 10.1 (IQR: 6.3-32.2). AHI showed statistically significant but weak correlations with age (r=0.207), weight (r=0.136), NC (r=0.273), and WC (r=0.184), whereas the association with ESS was stronger (r=0.649; all p<0.05). No significant correlations were observed with height or BMI. Patients with moderate-to-severe OSAS had higher NC, WC, ESS scores, symptom burden, and cardiometabolic comorbidities compared to those with normal-to-mild OSAS.

NC, WC, and ESS were associated with PSG-defined OSAS severity. However, correlations with age, weight, NC, and WC were weak in magnitude despite statistical significance, while BMI showed limited association. These routinely obtained measures may aid clinical assessment in sleep laboratory populations.