Risk factors for non-positional obstructive sleep apnea-hypopnea syndrome

To explore the main risk factors for non-positional obstructive sleep apnea (NPOSA).

A total of 560 patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) were divided into non-positional obstructive sleep apnea (NPOSA) and positional obstructive sleep apnea (POSA) groups. All patients were assessed by the Friedman staging system and anthropometry before overnight polysomnography. Blood tests were performed to determine the fasting blood glucose level and lipid profile. Forward logistic regression analysis was performed to evaluate the effects of all parameters on positional dependency.

The study sample consisted of 318 NPOSA patients and 242 POSA patients (88% and 85% were men, respectively). The mean apnea-hypopnea index (AHI) was 57.0 events/h in the NPOSA group, compared with 25.7 events/h in the POSA group. The POSA group had a significantly smaller neck circumference (NC), waist circumference (WC), hip circumference (HC), lower body mass index (BMI), AHI, fasting blood glucose, and apolipoprotein-B (apoB) levels than did the NPOSA group (all, P < 0.01). The minimal nocturnal oxyhemoglobin saturation (minSpO₂) and apoB/apoA ratio were higher in the POSA group than in the NPOSA group (both, P < 0.001). The AHI, minSpO₂, WC, and fasting blood glucose level were included in the logistic regression models.

The AHI, WC, minSpO₂, and fasting blood glucose level are the main independent risk factors for NPOSA.