Comparison of clinical features and surgical outcomes between hypopnea- and apnea-predominant obstructive sleep apnea

Shorter respiratory event duration is related to prevalence of type 2 diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is a heterogeneous sleep disorder often comorbid with metabolic diseases, and type 2 diabetes (T2DM) is one of them. Although apnea hypopnea index (AHI) is currently the diagnostic criteria for OSA severity, a controversial relationship between AHI and T2DM has been found. On the other hand, the duration of apnea-hypopnea events has been shown to be a useful metric for predicting mortality. This study aimed to test whether average respiratory event duration was associated with prevalence of T2DM.

METHODS

Patients referred to the sleep clinic were recruited in the study. Baseline clinical characteristics and polysomnography parameters including average respiratory event duration were collected. The association of average respiratory event duration with the prevalence of T2DM was evaluated by univariate and multivariate logistic regression analyses.

RESULTS

A total of 260 participants were enrolled, and 92 (35.4%) had T2DM. Univariate analysis revealed that age, body mass index (BMI), total sleep time, sleep efficiency, history of hypertension, and shorter average respiratory event duration were associated with T2DM. In multivariate analysis, only age and BMI remained significant. While average respiratory event duration was insignificant in multivariate analysis, subtype event analysis showed that shorter average apnea duration was both significant in univariate (OR, 0.95; 95% CI, 0.92-0.98) and multivariate analyses (OR, 0.95; 95% CI, 0.91-0.99). Neither average hypopnea duration nor AHI was associated with T2DM. Significant association (OR, 1.19; 95% CI, 1.12-1.25) was observed between shorter average apnea duration and lower respiratory arousal threshold after multivariate adjustment. However, causal mediation analysis revealed no mediating effect of arousal threshold on average apnea duration and T2DM.

CONCLUSION

The average apnea duration may be a useful metric in the diagnosis of OSA comorbidity. Shorter average apnea duration indicating poor sleep quality and augmented autonomic nervous system responses might be the potential pathological mechanisms leading to T2DM.

Obstructive Sleep Apnea Resolution in Hypopnea-Predominant versus Apnea-Predominant Patients after Maxillomandibular Advancement

This retrospective cohort study aimed: (1) to analyze the influence of apnea-predominant versus hypopnea-predominant obstructive sleep apnea (OSA) on surgical outcome after maxillomandibular advancement (MMA); and (2) to evaluate whether MMA alters the presence of apnea-predominant to hypopnea-predominant OSA more than vice versa. In total 96 consecutive moderate to severe OSA patients, who underwent MMA between 2010 and 2021, were included. The baseline apnea−hypopnea index, apnea index, and oxygen desaturation index were significantly higher in apnea-predominant group, while the hypopnea index was significantly higher in hypopnea-predominant group (p < 0.001). No significant difference was found between apnea-predominant group and hypopnea-predominant group in the degree of advancement of A-point, B-point, and pogonion. Surgical success and cure were significantly higher in the hypopnea-predominant group compared to the apnea-predominant group, 57.4% versus 82.1% (p = 0.021) and 13.2% versus 55.5% (p = 0.012), respectively. Of the 68 (70.8%) apnea-predominant patients, 37 (54.4%) shifted to hypopnea-predominant after MMA. Of the 28 (29.2%) hypopnea-predominant patients, 7 (25%) shifted to apnea-predominant postoperatively. These findings suggest that preoperative hypopnea-predominant OSA patients might be more suitable candidates for MMA compared to preoperative apnea-predominant OSA patients. Additionally, MMA proved to alter the presence of apnea-predominant to hypopnea-predominant OSA to a larger extend than vice versa.