Is the response rate of oral appliance therapy for subjects with and without position-dependent obstructive sleep apnoea different?

Objective To compare the effect of oral appliance (OA) treatment on non-position-dependent obstructive sleep apnoea (non-POSA) and position-dependent obstructive sleep apnoea (POSA). Methods The investigational sample was 205 patients with obstructive sleep apnoea at baseline and they were classified as non-POSA and POSA. Polygraphic registration was employed to compare the proportion of treatment responders between non-POSA and POSA groups at eight-week and one-year follow-ups. The treatment responder was defined as apnoea-hypopnoea index (AHI) <10 and/or >= 50% reduction in AHI. Results At the eight-week follow-up, the proportions of responders were 56% and 69% for the non-POSA and POSA groups (not significant), respectively. The responder proportions were increased to 68% and 77% for the two groups, respectively, at the one-year follow-up (not significant between the two groups). At the two follow-ups, there was no significant difference in absolute change in overall AHI between the two groups. However, the decrease in supine AHI was significantly greater in the POSA group, while the decrease in non-supine AHI was significantly greater in the non-POSA group. Conclusions The response rate for OA treatment did not differ between POSA and non-POSA groups. However, greater decreases in supine AHI and non-supine AHI were found among POSA and non-POSA patients, respectively.