Obstructive sleep apnea (OSA), the most common type of sleep-related breathing disorder [1], is characterized by recurrent, intermittent partial or complete collapse or obstruction of the upper respiratory tract during sleep [2]. Risk factors for its development include male gender, middle and older age, tobacco use, and obesity [3,4]. The high worldwide prevalence and increased risk of morbidity and mortality, especially due to cardiovascular diseases, make OSA a serious health-related global problem [5-7]. In addition, OSA can negatively affect the patient’s quality of daily life (QoL) [8]. For instance, excessive daytime sleepiness; impaired cognitive functions; work performance; ability to concentrate; or the occurrence of depression, headaches, snoring, and nocturnal urination; or disharmony in social interactions are particularly limiting [9,10]. The gold-standard treatment for OSA is continuous positive airway pressure (CPAP). The aim of CPAP therapy is to reduce the frequency of apneic and hypopneic pauses during sleep [11,12]. It is increasingly recommended to use alternative or additional therapy options in combination with CPAP [13]. These options include lifestyle and nutrition interventions, physical activity, pharmacotherapy, and behavioral therapy [13]. A recent meta-analysis has shown that a positive effect of exercise therapy, together with a reduction-diet intervention, leads to a significant reduction in the severity of OSA [14]. Based on several meta-analyses, the severity of the disease could be improved either by adjusting to a more nutritional lifestyle [14-16] or by implementing a physical intervention [17,18]. A significant reduction in the apnea-hypopnea index (AHI) was also achieved by training orofacial muscles with oropharyngeal exercises (ie, myofunctional therapy) [19]. According to Camacho et al [19], myofunctional therapy could represent an additional part of OSA therapy. Even the standard treatment representing CPAP therapy or mandibular advancement devices should also include exercise training [20]. A recent meta-analysis also showed a positive effect of respiratory therapy and respiratory muscle training elements in influencing OSA [21]. However, the authors stated that further research is needed to confirm the effect of additional therapeutic options already mentioned [12,15,17-19,21].

Aerobic and respiratory muscles training, oropharyngeal exercises, and regimen recommendations concerning lifestyle, nutrition, and behavior changes are individual components of the comprehensive home-based remotely supervised rehabilitation (tele-RHB) program conceived in this study. No recent literature has been found that deals with the effects of a similar and thus complex remotely supervised intervention. The absence of such an intervention in the context of OSA, as a possible therapeutic option for additional at-home training in combination with CPAP therapy, was the reason for conducting our research.

This study protocol describes the first-ever randomized controlled trial to solely evaluate the effectiveness of the tele-RHB program among male adults with moderate to severe OSA. This study aims to assess whether completing a comprehensive telerehabilitation program and CPAP therapy positively affects the severity of OSA, QoL, body composition and circumferences, exercise tolerance, lipid profile, and respiratory muscle and lung function. Our hypothesis is that a combination of tele-RHB program and CPAP therapy will be more effective in the reduction of OSA severity and improvement of QoL, body composition, exercise tolerance, lipid profile, as well as respiratory muscle and lung function, compared to CPAP therapy alone.

This study is a 2-arm parallel single-blind randomized controlled trial (registered on ClinicalTrials.gov: NCT04759456), with the per-protocol analysis investigating the effect of the tele-RHB program among 50 male patients with newly diagnosed OSA indicated to CPAP therapy. Patients were recruited from the Sleep Centre of the International Clinical Research Center of St Anne's University Hospital in Brno (FNUSA-ICRC). After providing informed consent, the patients will be randomized to the 12-week tele-RHB program along with CPAP therapy; 25 patients will be randomized to the intervention arm, and 25 will be in the control arm (CPAP therapy alone) in a 1:1 ratio, following the methods described below (Figure 1).

The study protocol follows the Declaration of Helsinki and received approval from the Ethics Committee of the University Hospital Brno in the Czech Republic (06-090920/EK). Participation in the study will be voluntary, without any compensation or remuneration, and participants will be allowed to withdraw from the study at any moment without providing a reason.

All participants will provide written informed consent. This informed consent form provides details about the purpose of the study, requirements for study participation, randomization process, personal data processing, storage and protection process, and contact information for research team staff. The original informed consent allows the secondary analysis of obtained data without additional consent.

All participants’ obtained data will be pseudonymized and deidentified; only an authorized person of the study research team will be able to identify the participants on the basis of personal data. The obtained data will be published anonymously, and no report or publication will contain any data that could lead to the participants’ identification.

Participants will be eligible if they are male patients, aged 30-60 years, have newly diagnosed OSA with an AHI ≥15 episodes per hour, are indicated to CPAP therapy, and are interested in our adjunct tele-RHB program.

Participants are excluded if they have another type of OSA treatment, chronic corticosteroid therapy or long-term oxygen therapy; they are also excluded if they have at least one of the following health problems: central sleep apnea, chronic obstructive pulmonary disease III or IV, severe pulmonary hypertension, New York Heart Association III or IV, acute coronary syndrome, heart failure, ejection fraction <40%, electrocardiographic-documented heart arrhythmia, severe heart valve disease, cerebrovascular disease, psychiatric disease, and physical disability; in addition, they will be excluded if they do not cooperate during the intervention or do not follow the tele-RHB program and CPAP therapy protocol.

The patients who meet the inclusion criteria will be recruited from the Sleep Centre of the FNUSA-ICRC. The details of the study overview are shown in Table 1. On the first visit, patients will undergo polysomnography (PSG), blood sampling for lipid profile, and completion of the Epworth Sleepiness Scale (ESS) with a known score. Those who are found to have moderate to severe OSA will be contacted for further intervention alongside the standard CPAP therapy. These patients will be verbally informed and will receive an information leaflet about the ongoing study of the 12-week tele-RHB program. Then, they will complete anthropometric and spirometric examinations, measurements of maximal inspiratory mouth pressure (MIP) and maximal expiratory mouth pressure (MEP) as well as body composition, 6-minute walk test (6MWT), and QoL questionnaires in the Cardiovascular Rehabilitation Clinic at the University Hospital Brno (CRC-UHB). After that, during the interview with a physiotherapist, participants will receive detailed and comprehensive information regarding their possible participation in the study. Then, potential participants will be given at least 24 hours to decide before signing the informed consent.

On the second visit, patients who agreed to participate in the study will sign the informed consent form and will be then randomized 1:1 to the intervention or control group.

On the third visit, participants of both groups will undergo individual titration of CPAP therapy at the Sleep Centre of the FNUSA-ICRC. The intervention group will subsequently receive education about the tele-RHB program, along with theoretical and practical instruction on its individual components in the CRC-UHB. Participants of the intervention group will also receive a training brochure containing information needed for the tele-RHB program with remote supervision by a physiotherapist.

After the completion of the 12-week tele-RHB program, on the fourth visit, participants of both groups will undergo the same examinations and measurements as those conducted at the baseline, at the Sleep Centre of the FNUSA-ICRC and in the CRC-UHB.

After 1 year from the 12-week tele-RHB program’s completion, on the fifth visit, participants of both groups will undergo the same examinations and measurements as they did at the baseline in both health facilities.

Participants will be randomized 1:1 to the intervention and control group by a noninvestigating member of the research group in the CRC-UHB with the help of the website “randomization.com” [22] into 6 blocks of 8 and 1 block of 2 participants. Participants and caregivers will be instructed not to comment on their ongoing therapy. The outcome assessor will be blinded. Physiotherapists who educate the intervention group participants about the tele-RHB program and who carry out regular teleconsultations during this program are the only unblinded members of the research group.