Long-term follow-up of a randomized controlled trial of oral appliance therapy in obstructive sleep apnea

Background: Long-term trials are needed to capture information regarding the persistence of efficacy and loss to follow-up of both mandibular advancement device (MAD) therapy and continuous positive airway pressure (CPAP) therapy.

Objectives: The aim of the study was to compare these treatment aspects between MAD and nasal CPAP (nCPAP) in a 1-year follow-up.

Methods: Forty-three mild/moderate obstructive sleep apnea patients (52.2 ± 9.6 years) with a mean apnea-hypopnea index (AHI) of 20.8 ± 9.9 events/h were randomly assigned to two parallel groups: MAD (n = 21) and nCPAP (n = 22). Four polysomnographic recordings were obtained: one before treatment, one for the short-term evaluation, and two recordings 6 and 12 months after the short-term evaluation. Excessive daytime sleepiness (EDS) was also evaluated at the polysomnographic recordings.

Results: The initially achieved improvements in the AHI remained stable over time within both groups (p = 0.650). In the nCPAP group, the AHI improved 4.1 events/h more than in the MAD group (p = 0.000). The EDS values showed a gradual improvement over time (p = 0.000), and these improvements were similar for both groups (p = 0.367). In the nCPAP group, more patients withdrew from treatment due to side effects than in the MAD group.

Conclusions: The absence of significant long-term differences in EDS improvements between the MAD and the nCPAP groups with mild/moderate obstructive sleep apnea may indicate that the larger improvements in AHI values in the nCPAP group are not clinically relevant. Moreover, nCPAP patients may show more problems in accepting their treatment modality than MAD patients.