Increased diastolic blood pressure and apnea time contribute to the poor apnea and hypopnea index and life quality of primary snoring: a cohort study combined with external validation.

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is a common sleep breathing disorder closely associated with cardiovascular disease. However, the respiratory sleep and related cardiovascular parameters on the apnea and hypopnea index (AHI) and life quality of primary snoring are unclear. We launched a cohort study focused on the association between respiratory sleep and cardiovascular-related parameters and apnea and hypopnea index, incorporating data from 218 patients with primary snoring in our medical center between Jun 1, 2015, and Apr 1, 2016. Thirty patients from Sichuan Cancer Hospital were used for validation. Patients with longer apnea time were more likely to progress to higher AHI (> 30) than controls (OR = 5.66, 95% CI = [2.79, 11.97],  < 0.001). Similarly, if patients have a higher value of diastolic blood pressure, they will also have a higher AHI (> 30) (HR [95% CI] = 3.42 [1.14, 13.65],  = 0.043). According to multivariate analysis, longest apnea time, the mean percentage of SaO2, and neckline length were independent risk factors of overall survival. A predictive model developed based on these factors above yielded a favorable agreement (C-index = 0.872) on the calibration curve. Thirty patients conducted external validation from Sichuan Cancer Hospital, displaying an AUC of 0.833 (0.782-0.884). Increased diastolic blood pressure and apnea time affect AHI level. An AHI prediction model based on these factors above can help clinicians predict the risk of high AHI events.