The Risk Factors and Predictors of Chronic Obstructive Pulmonary Disease in Patients With Obstructive Sleep Apnea–Hypopnea Syndrome at Plateau

Background

OSAHS patients with COPD (i.e., overlap syndrome) have a significantly worse prognosis than those with OSAHS alone, and the role of plateau hypoxia in the occurrence of the disease is still unclear. This underscores the urgent need to explore the risk factors for the incidence of COPD in patients with OSAHS and to identify predictors for the occurrence of overlap syndrome at plateau.

Methods

Fifty patients with OSAHS and 34 patients with overlap syndrome were enrolled in this study. Demographic, auxiliary examination, and laboratory data were collected.

Results

All patients enrolled were obstructive sleep apnea–hypopnea syndrome. The apnea–hypopnea index (AHI), the number of hypopnea, and the oxygen desaturation index were higher in the group of patients with overlap syndrome than in the group of patients with OSAHS. The mean pulse oxygen saturation was lower than that in the group of patients with OSAHS (p < 0.05). The right heart structure and function indexes (PASP, right atrial transverse diameter, RVTD, BNP, TNI) in patients with overlap syndrome were worse than those in patients with OSAHS (p < 0.05), and this worse cardiovascular status was positively correlated with inflammatory factors such as high-sensitivity C-reactive protein, IL-6, and PCT (p < 0.05). Binary logistic regression analysis indicated that PASP, smoking index, and AHI were independent risk factors for OSAHS developing into overlap syndrome. ROC curve showed that the area under the curve of the combination of the three markers for predicting overlap syndrome was 0.908 (95% CI 0.843–0.974, p = 0.000), with a sensitivity of 0.882 and a specificity of 0.820. The optimal cutoff values for PASP were 42.5 mmHg, 15 for the smoking index, and 25.65 for the AHI based on the Youden index.

Conclusions

Our study reveals that overlap syndrome has more frequent nighttime hypopnea and hypoxia than OSAHS alone. The cardiovascular complications of overlapping syndromes at plateau are more pronounced, possibly due to the exacerbation of the systemic inflammatory response. The combination of PASP, smoking index, and AHI can be a powerful tool for predicting and assessing the occurrence of COPD in OSAHS patients from plateau populations in China. These findings have the potential to significantly improve the management and prognosis of patients with overlap syndrome.