Evolution of mild obstructive sleep apnea after different treatments

STUDY OBJECTIVES: To evaluate the prognosis of mild obstructive sleep apnea in relation to different treatment modalities. STUDY DESIGN: An open, retrospective, longitudinal follow-up study. METHODS: Fifty adult patients diagnosed and treated for mild obstructive sleep apnea at the Department of Otorhinolaryngology at Kuopio University Hospital between 1998 and 2004 had a control polysomnography in 2005. The changes in apnea-hypopnea index (AHI) were observed in untreated (n = 28), operative (n = 11), and continuous positive airway pressure (n = 11) treatment groups at a long-term follow-up visit. RESULTS: The mean follow-up period was 4 (range, 1.3-9.0; SD, 1.9) years. The untreated patients had a statistically significant increase in AHI (13.3, SD 18.3) at the follow-up. Half of these patients developed a moderate or severe degree of sleep apnea, and only 11% were cured. In patients who were treated with continuous positive airway pressure, the degree of obstructive sleep apnea became worse in 64% of cases, and in 27% of patients, the AHI returned to normal (<5). The degree of obstructive sleep apnea in operated patients deteriorated only in 18%, and in 27% of the patients, the AHI returned to normal (<5). CONCLUSIONS: Mild obstructive sleep apnea has a natural tendency to worsen with time. Active treatment of mild obstructive sleep apnea appears, therefore, to be advisable.