Objective and subjective adherence to oral appliance therapy in adults with obstructive sleep apnea: pilot data from a one-year longitudinal study

OBJECTIVES: To evaluate objective and subjective adherence to oral appliance (OA) therapy in obstructive sleep apnea (OSA) and identify predictors of adherence. METHODS: Forty-nine adults with OSA (27 males, 22 females) underwent baseline polysomnography, sleep questionnaires, craniofacial measurements, and personality assessment. Objective adherence was monitored for 3 months using an embedded thermal microsensor. Subjective adherence was self-reported at 3 and 12 months. Predictors of adequate adherence (mean nightly use ≥ 4 h) were identified using multivariate logistic regression under a modified intention-to-treat approach. RESULTS: OA therapy reduced AHI from 16.6 ± 10.3 to 4.16 ± 3.05 events/h. Forty-three participants (87.8%) completed the 3-month follow-up, and were all contacted at 12 months. During the first 3 months, mean use was 7.05 h on nights worn and 3.85 h/night overall, with OA used on 3.7 days/week and ≥ 4 h on 55.7% of nights. Participants overestimated use frequency (P < 0.001) but not nightly duration. At 3 months, 49% were adherent, showing stable use, whereas non-adherent users wore the appliance on fewer nights; at 12 months, 44% remained adherent, while most non-adherent users discontinued therapy. Older age and lower baseline ESS predicted 3-months adherent, while older age and smaller mandibular plane angle predicted 12-months adherent. CONCLUSION: Adherence to this type of OA was suboptimal in this study, with patients overestimating use frequency but accurately reporting nightly duration. Older age predicted adherence at both 3 and 12 months, while lower baseline sleepiness and smaller mandibular plane angle were associated with 3- and 12-month adherence, respectively. CURRENT KNOWLEDGE/STUDY RATIONALE: Subjective adherence to oral appliance (OA) therapy in patients with obstructive sleep apnea (OSA) may overestimate actual device use, whereas longitudinal adherence patterns and their clinical implications remain poorly understood. STUDY IMPACT: Objective adherence to OA therapy was substantially lower than self-reported adherence, particularly among poorly adherent patients. Early adherence patterns may help clinicians identify patients who require additional adherence support. In the absence of regular adherence reminders, OA use frequency remained insufficient, potentially limiting the systemic benefits of OA therapy for OSA. Long-term, objective, and individualized adherence care and monitoring may be important in routine clinical practice.