The association of body mass index values with severity and phenotype of sleep-disordered breathing

To investigate the relationship between body mass index (BMI) and the severity of obstructive sleep apnea (OSA) and to determine the BMI cut-off values for sleep-disordered breathing among adult population.

Data from 515 patients were evaluated retrospectively. These included demographic data, BMI, apnea-hypopnea index (AHI), oxygen saturation (SaO2) and oxygen desaturation index (ODI). The BMI cutoff value for sleep-disordered breathing was determined and comparisons were made between two groups of patients (BMI ≤ 33 and BMI > 33). Descriptive and comparative analyses were performed using SPSS, version 24.

Higher BMI values were found to be correlated with diagnosis and severity of OSA and reduced sleep efficiency. Patients in the BMI > 33 group had significantly higher rates of co-morbid diseases than patients in the BMI ≤ 33 group. Patients with BMI ≤ 33 had significantly lower ODI values than patients with BMI > 33. In patients with BMI > 33, arousal index was significantly higher and SaO2 values were lower than those with BMI ≤ 33. In rapid eye movement (REM) sleep-related OSA, BMI values were higher than positional/classical OSA.

Patients with higher BMI experienced frequent nocturnal oxygen desaturation periods resulting in higher arousal indexes and decreased sleep efficiency. REM sleep-related OSA and high BMI values together may lead to increased nocturnal oxygen demand. We recommend the threshold values of BMI > 33 to be considered for screening OSA among adult population.