Phenotypic differences in airway obstruction as determined by VOTE score.

Objective: 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).

Methods: 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.

Results: 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).

Conclusions: 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.