cost-effectiveness of obstRuctivE Sleep apnea Therapy (REST study):
Comparison of MRA therapy versus CPAP therapy in moderate OSAS

Obstructive sleep apnea syndrome (OSAS) is an underdiagnosed, undertreated and
highly prevalent disease (4% of middle-aged men and 2% of women). It is
characterized by repetitive upper airway collapse during sleep, disruptive
snoring and excessive daytime sleepiness (EDS). OSAS is defined by a
combination of these symptoms and laboratory findings. Laboratory findings
should demonstrate an apnea-hypopnea index (AHI) of five or more. As obesity is
the most important risk factor for OSAS and the number of people with obesity
is increasing, the prevalence as well as the incidence of OSAS will almost
certainly increase even further, as is clear already in the USA. Moreover, OSAS
is an important risk factor for sick leave, work disability, cardiovascular
co-morbidities, and becoming involved in traffic accidents. Appropriate
treatment will subsequently reduce these symptoms and co-morbidities. Given the
large impact on patients in terms of health and society in terms of costs,
cost-effective treatment is necessary.
According to the CBO guideline *Diagnostics and treatment of the obstructive
sleep apnea syndrome in adults*, in moderate OSAS both MRA and CPAP can be
considered as primary interventions as both are proven to be effective in
reducing the AHI. Although MRA is generally considered less effective than
CPAP, it was shown that MRA is not inferior to CPAP regarding AHI in non-severe
OSAS and that many patients report greater satisfaction with MRA.
Cost-effectiveness of CPAP and MRA is only documented on EDS in the USA and
Canada. Therefore, proper cost-effectiveness analysis with AHI as primary
outcome in this specific OSAS group in the Netherlands is still needed.

To compare the cost-effectiveness and effectiveness of MRA therapy versus CPAP
therapy in patients with moderate OSAS.

In a randomized parallel controlled study patients will be randomly assigned to
either MRA therapy or CPAP therapy. Group A receives MRA. Group B receives
CPAP. Both treatment periods last for 12 months. The total duration of the
study is 12 months. Measurements will be done at baseline, after 3, 6 and 12
months.

Patients in group A are treated with a bibloc MRA (SomnoDent). It positions the
patient's mandible in a forward and downward position thereby *stretching* the
upper airway. The mandible will be set at 70% of the patient*s maximum
advancement and will be adjusted to the convenience of the patient. Titration
will be continued until symptoms abate or until further advancement causes
discomfort.
Patients in group B are treated with CPAP therapy. The proper CPAP-pressure is
set for each patient separately. Patients are fitted
with a comfortable CPAP mask before titration of the CPAP-pressure. For
CPAP-titration, patients are instructed to adopt their
own typical sleeping habits.

The burden for the patient will be the time investment (visits to outpatient
center, filling in diary and questionnaires), and undergoing medicial
examinations (primary and secondary outcomes).
During the initial period of use of MRA patients commonly report discomfort of
the teeth and jaws, gum irritation, excessive salivation or a dry mouth. Mild
pain of the masticatory muscles and temporomandibular joint often occur. In
many cases the adverse effects are transient and disappear with continued use.
One of the main problems encountered in patients using CPAP is pressure-related
discomfort or intolerance. Patients complain about nocturnal awakenings,
claustrophobia, mouth and mask leak and nasal problems, such as dryness,
congestion, rhinorrhea and sneezing.

Benefits of the treatments could be a reduction in AHI, reduction of EDS,
improvement in quality of life, and on the long term reduction in
cardiovascular risk.