[Treatment outcome evaluation of different mandibular advancements using oral appliance to treat obstructive sleep apnea and hyponea syndrome: a systematic review].

OBJECTIVE: To evaluate the polysomnology results along with mandibular titrated advancement using oral appliance to treat obstructive sleep apnea and hyponea syndrome (OSAHS).

METHODS: Several electronic databases (PubMed, Embase, Cochrane Library, CNKI, VIP, and Wanfang) were systematically searched up to September 2015. There was no restriction of language or source of information. All randomized clinical trials (RCT) and before-after trials (BAT) comparing at least two different mandibular advancements were included. Two independent reviewers selected the studies, extracted data and evaluated risk of bias by quality assessment. Data were pooled using a fixed-effects model, and the summary effect measure was calculated by risk ratio (RR) and 95%CI. Meta-analysis was performed using RevMan 5.3 software.

RESULTS: Two RCTs and five BATs were included in the review. Among the five BATs, two of them were randomized, while the other three were not. Outcomes including apnea hypopnea index (AHI), oxygen desaturation index (ODI), success rate (reduction of AHI or ODI >50%), normalization rate (AHI or ODI<10/h) were assessed in this review. Based on the trial design and quality assessment, four studies were included for meta-analysis. No significant difference in the success rate was found between the group with 50% of the maximal mandibular advancement (MMA) and the group with 75% of MMA [I2=0%, RR=0.93, with 95%CI (0.80, 1.09)]. No significant difference in the normalization rate was found between the 50% of MMA and 75% of MMA groups [I2=45%, RR=0.85, with 95%CI (0.68, 1.06)]. Subgroup analysis displayed that the severity of OSAHS before treatment was a potential factor affecting the normalization rate.

CONCLUSION: Based on current available evidence, the success rate and normalization rate for treating OSAHS in the patients with 75% MMA were not found to be significantly higher than those with 50% MMA. Due to small simple size in this meta-analysis, the results of the present study should be interpreted with caution. Further prospective studies are needed to strengthen the evidence.