Phenotypic differences in airway obstruction as determined by VOTE score

The objective if this study was to investigate phenotypic differences in airway obstruction, as determined by VOTE score, in a cohort of patients with obstructive sleep apnea (OSA) undergoing drug-induced sleep endoscopy (DISE).

Patients older than 18 years of age scheduled for DISE by one surgeon at a tertiary care center from July 2016 to July 2022 were included in a single-center retrospective cohort study. Patient demographics, body mass index (BMI), apnea-hypopnea index (AHI), and VOTE scores were extracted. Spearman correlation tests were utilized to determine the relationship between variables, and statistical analyses were performed using R.

The study included 165 patients (61.24 years, SD 11.57; BMI 31.04 kg/m², SD 6.05). Due to several significant relationships between VOTE scores and patient demographics, a cluster analysis was performed, in which two distinct clusters (phenotype 1 and phenotype 2) arose. Phenotype 1 patients had lower overall VOTE scores (p < 0.001), less obstruction at the velum (p < 0.001) and oropharynx (p < 0.001), significantly more tongue obstruction (p = 0.031), and a significantly lower BMI (p = 0.001). Though not reaching significance, phenotype 1 patients also had more epiglottic obstruction (p = 0.0841) and were older (p = 0.2775).

Patients suffering from OSA may be categorized into one of two distinct phenotypes of clinical significance. Phenotype 1 patients who are nonobese and have less significant obstruction overall, with increased obstruction at the tongue, may benefit greatly from targeted surgical modalities. Conversely, phenotype 2 patients with worse obstruction on DISE and increased velum and oropharynx obstruction may represent a phenotype of OSA that is increasingly difficult to treat surgically, due to body habitus and severe, multi-level obstruction.