Dropout and adherence of obstructive sleep apnoea patients to mandibular advancement device therapy: A systematic review of randomised controlled trials with meta-analysis and meta-regression

Background: Mandibular advancement devices (MADs) are used as an alternative to continuous positive airways pressure to treat obstructive sleep apnoea (OSA) patients, but to date, specific data on the adherence to MAD therapy are lacking. Objectives: The aim of the present systematic review was to investigate the dropout rate and adherence of OSA patients to different custom-made (CM) and non-custom-made (NCM) MAD therapies. Search Methods: An electronic search was performed in MEDLINE, Cochrane Database of Systematic Reviews, Scopus, LILACS and Web of Science. Selection Criteria: Randomised controlled trials (RCTs) assessing the compliance to customised and not customised MADs in the treatment of adult OSA patients were included. Data Collection and Analysis: The quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) and the risk of bias by the Cochrane Collaboration's tool for assessing risk of bias in RCT. The dropout rate of each study was computed and the adherence to MAD therapy in terms of hours per night and nights per week was extracted from each study. Results: Thirty-two RCTs were included. The risk of bias resulted low in most of the studies. The GRADE scores indicated that the quality of evidence was from very low to moderate. The meta-analyses showed that the mean dropout rate did not significantly differ between CM and NCM MADs: The overall mean dropout rate was 0.171 [0.128–0.213] with a mean follow-up of 4.1 months. The hours per night adherence was significantly higher for CM MADs (6.418 [6.033–6.803]) compared to NCM MADs (5.107 [4.324–5.890]. The meta-regression showed that the dropout rate increases significantly during time (p <.05). Conclusions: There is a very low to moderate quality of evidence that the dropout rate of MAD therapy is similar among CM and NCM MADs, that the dropout rate increases significantly during time and that CM MADs have higher hours per night adherence compared with NCM MAD. Registration: The study protocol was registered on PROSPERO (n. CRD42020199866).