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. 2023 Mar 22;37(1):2023.1.ar. doi: 10.11607/ofph.2023.1.ar

Currents in Dental Sleep Medicine

PMCID: PMC10644913
J Oral Facial Pain Headache. 2023 Mar 22;37(1):2023.1.ar.

The Outcome of Oral Appliance Therapy on Position-Dependent Obstructive Sleep Apnea: A Multicenter Randomized Controlled Trial. Fransson AMC, Isacsson G, Nohlert E. Am J Orthod Dentofac Orthop 2022;162:386–393.

Takafumi Kato

Previous studies have demonstrated that the supine sleeping position can exacerbate obstructive sleep apnea (OSA) and that certain individuals exhibit positional OSA (POSA), wherein the OSA severity is substantially more pronounced in the supine position than in the lateral position. Therefore, studies have evaluated the success of treatments for OSA, such as oral appliance (OA) therapy, in individuals with and without POSA. However, there is inconsistent evidence regarding whether individuals with POSA have a better response to OA treatment compared to individuals without POSA.

This study tested the hypothesis that individuals with POSA at baseline would have a higher treatment response rate than individuals without POSA. The study conducted a secondary analysis of the data from previously published works, evaluating in total a large number of patients with moderate to severe OSA over an 8-week period (n = 205) and 1 year (n = 139) after using an OA (either a bibloc or monobloc appliance). A 1-night home sleep testing (HST) was performed at baseline, 8 weeks, and 1 year. After the baseline HST, the subjects were divided into two groups based on the presence or absence of POSA. Categorization was based on whether the subjects slept for at least 15 minutes in each position. POSA was defined as having an apnea-hypopnea index (AHI) at least two times higher in the supine position compared to the nonsupine position. The criterion for a positive response was met when a patient had an AHI of less than 10 and/or a reduction of at least 50% in their baseline AHI during the evaluation visit.

The results showed that there was no significant difference in the proportion of responders between the non-POSA group and the POSA group at the 8-week or 1-year follow-ups. The proportion of responders increased from 56% at 8 weeks to 68% at 1 year in the non-POSA group and from 69% to 77% in the POSA group, but these differences were not significant. The decrease in AHI score in all sleeping positions at 8 weeks was greater in the non-POSA group than in the POSA group, but this difference was not significant. Interestingly, there was a significantly greater decrease in supine AHI among subjects with POSA, while the decrease in nonsupine AHI was significantly greater in the non-POSA group, an effect that persisted at the 1-year follow-up.

Collectively, the study hypothesis that individuals with POSA at the start of OA treatment would have a higher rate of treatment response compared to those without POSA was not supported by the results. However, this study provides important clinical insights into the effectiveness of OA treatment for different forms of OSA and emphasizes the importance of considering positional therapy in its treatment.1,2

This study’s limitations and inconsistencies with other studies suggest that more research is needed to better understand the relationship between POSA and response to OA treatment. The exclusion of one-third of the sample population puts the study’s power into question, although the sample size was almost sufficient to detect a significant difference between the POSA and non-POSA groups. The study found that about half of the non-POSA patients shifted to POSA and about one-third of POSA patients shifted to non-POSA during the 8-week evaluation. The reason for this shift is unknown, but it could be due to insufficient monitoring or natural shifts between nights. Recent studies suggest that changes in body position affect the phenotypic traits and individual characteristics of OSA.1,2 To enhance the accuracy of OSA diagnosis and treatment using OA, the roles of position-dependent alterations in OSA characteristics need to be clarified with other phenotypes like pharyngeal collapsibility, loop gain, and respiratory arousal threshold.3Therefore, future challenges include the standardization of POSA definitions and the complexity of analyzing positional dependence.

References

  1. Oksenberg A, Gadoth N. Positional patients (PP) and non positional patients (NPP) are two dominant phenotypes that should be included in the phenotypic approaches to obstructive sleep apnea. Sleep Med Rev. 2018;37:173–174. doi: 10.1016/j.smrv.2017.05.004. [DOI] [PubMed] [Google Scholar]
  2. Eckert DJ. Phenotypic approaches to positional therapy for obstructive sleep apnoea. Sleep Med Rev. 2018;37:175–176. doi: 10.1016/j.smrv.2017.06.007. [DOI] [PubMed] [Google Scholar]
  3. Eckert DJ. Phenotypic approaches to obstructive sleep apnoea—New pathways for targeted therapy. Sleep Med Rev. 2018;37:45–59. doi: 10.1016/j.smrv.2016.12.003. [DOI] [PubMed] [Google Scholar]
J Oral Facial Pain Headache. 2023 Mar 22;37(1):2023.1.ar.

Non-sleepy Obstructive Sleep Apnoea: To Treat or Not to Treat? Altintas N, Riha RL. Eur Respir Rev 2019;28:190031.

Dennis Bailey

There is a developing and controversial position that the management of nonsleepy patients diagnosed with OSA is of little value and may not be necessary. The basis of this argument is the lack of evidence related to any benefits of addressing the various comorbidities associated with untreated OSA, particularly cardiometabolic disorders and quality of life (QOL) issues. The premise here is that the treatment of OSA/hypopnea syndrome (OSAHS) should not be viewed in a similar fashion to other illnesses or diseases. This is predicated on the basis that, as a disorder, the treatment is directly related to “self-management”; ie, ongoing use of CPAP or an OA.

The focus of this review was on the use of CPAP and the adherence to use, which is cited as 60% in nonsleepy patients and 77% in sleepy patients after 2 years of use. In addition, the number of hours of use is also a consideration and needs to be evaluated as well. A citation in this review looked at a seminal paper that determined that, at 4 hours per night, self-reported sleepiness was improved, at 6 hours per night objective sleepiness was even more improved, and at 7.5 hours per night there was improvement in functional status. However, this study focused on those with severe OSAHS, which is viewed as patients with an AHI that is 30 or greater and is the group associated with the most significant risk for comorbid diseases, such as cardiovascular disease, elevated blood pressure, and insulin resistance. This needs to be studied more in the mild to moderate OSA group, a population frequently managed with OAs by dentists.

What has become an issue related to all of this is the developing controversy over the use of a metric for defining AHI. AHI is no longer viewed as the most predictive outcome of morbidity and mortality; oxygen desaturation and hypoxic burden seem to be dominant factors based on current evidence. Furthermore, based on the third edition of the International Classification of Sleep Disorders (ICSD-3), OSAHS is considered to be present when the AHI is 5 or greater and when there are symptoms of sleepiness, insomnia, or snoring, or the presence of associated medical comorbidities such as hypertension, coronary artery disease, and atrial fibrillation. The “to treat or not to treat” then becomes a challenge for the clinician. In the absence of these signs and symptoms, a diagnosis of OSA is positive when the AHI is 15 or greater. The assumption is that treatment should commence under these conditions because they are being driven by their presence; currently, there is very little evidence to support this.

Another related issue of concern is the ability to accurately define excessive daytime sleepiness (EDS). Historically, this has been associated with the use of the Epworth Sleepiness Scale, which has limitations and is very subjective. It is known that the Epworth Sleepiness Scale is not strong and accurate for the diagnosis of OSA in women or younger individuals. This becomes additionally problematic, since OSA and OSAHS are not the only sleep disorders associated with sleepiness and EDS. In addition, there are data indicating that, despite the use of CPAP in moderate to severe OSAHS, sleepiness may continue to persist. Of greatest significance is that CPAP use can result in a modest improvement in blood pressure control, as well as in markers for cardiovascular and metabolic health; however, these results are less consistent for patients with OSA and who are not sleepy. Current phenotyping of risk factors and anatomical-physiologic variables in treatment selection is progressing. The era of “one size (one treatment) fits all” is not effective anymore.

All of the reviews on this topic are centered around the quantification of various areas that can be measured, such as the AHI, oxygen/hypoxic burden, blood pressure, and other health-related conditions. As is discussed, these do not always respond in a like manner based on the presence of sleepiness. One area that is mentioned but does not receive significant discussion is QOL. In the future, more consideration of QOL and, more specifically, health-related QOL (HRQOL) needs to be considered, as well as improved methods for assessing sleepiness. Whatever treatment modality selected needs to be used—without adherence, no benefit is expected. Sleepiness or EDS is not exclusively associated with OSA and OSAHS; thus, other sleep disorders, such as the co-existence of comorbid insomnia and sleep apnea (COMISA), need to be considered.

Articles from Journal of Oral & Facial Pain and Headache are provided here courtesy of MRE Press

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