[Follow-up study on natural course changes of obstructive sleep apnea hypopnea syndrome among young and middle aged...

Objective: To explore the natural course of obstructive sleep apnea-hypopnea syndrome (OSAHS) and its associated factors in young and middle-aged patients with OSAHS. Methods: A total of 52 young and middle-aged OSAHS patients were recruited in this study from West China Hospital of Sichuan University. All patients were performed twice overnight polysomnography (PSG) examinations. At the baseline, patients underwent the first PSG and clinical evaluation from September 2009 to September 2017 and the patients received the second PSG from January 2017 to January 2019. During the follow-up period, these patients had no treatment. All patients were categorized into two groups including mild-to-moderate [5/h≤ apnea-hypopnea index (AHI)<30/h] group and severe (AHI ≥ 30/h) group according to the baseline AHI value. Differences in the clinical characteristics and PSG variables between baseline and follow-up were compared in two groups separately using t-tests or Mann-Whitney U test. The general linear correlation analysis was used to explore the factors related to the severity of OSAHS including AHI, the mean oxyhemoglobin saturation and the minimal oxyhemoglobin saturation during the follow-up period. Results: This study recruited 28 OSAHS patients in mild-to-moderate group [mean age, (39.7±10.2) y] and 24 patients in severe group [mean age, (41.0±7.1) y]. Compared to the baseline, there was a significant increase in AHI value [(45.0±25.3) vs (33.6±27.3)/h, P<0.001] in all OSAHS patients. Notably, the increase of AHI was more significant in the mild-to-moderate OSAHS group [(32.1±22.2) vs (13.6±8.7)/h, P<0.05] but not in severe OSAHS patients [(60.7±19.5) vs (58.0±21.5)/h, P>0.05]. A person correlation analysis revealed that the AHI value was positively related to the age (r=0.531, P=0.004) in mild-to-moderate OSAHS patients. Conclusion: The severity of OSAHS is increased with the age in young and middle-aged patients with mild-to-moderate OSAHS, but not in those with severe OSAHS.