Difficulty Falling Asleep is Associated with Poorer Therapeutic Outcomes in Unilateral Hypoglossal Nerve Stimulation

Abstract

Purpose

The coexistence of insomnia and obstructive sleep apnea (OSA) is very prevalent. Hypoglossal nerve stimulation (HGNS) is an established second-line therapy for patients suffering OSA. Studies investigating the effect of the different aspects of insomnia on the therapeutic outcome are largely missing. Therefore, this study aimed to understand the impact of the different aspects of insomnia on the therapeutic outcome under HGNS therapy in clinical routine.

Patients and Methods

This is a retrospective study including 30 consecutive patients aged 55.40 ± 8.83 years (8 female; 22 male) undergoing an HGNS implantation in our tertiary medical center between 2020 and 2023. All patients underwent preoperative polysomnography (PSG) according to AASM. First follow-up PSG was performed 95.40 ± 39.44 days after activation (30 patients) and second follow-up PSG was performed 409.89 ± 122.52 days after activation (18 patients). Among others, the following PSG-related parameters were evaluated: apnea–hypopnea index (n/h) (AHI) and oxygen desaturation index (n/h) (ODI). Insomnia was assessed by the insomnia severity index (ISI) questionnaire. Preoperatively, all patients included filled out each ISI item. Spearman's-rho correlation coefficient was calculated for correlations.

Results

Preoperative score of ISI item 1 (difficulty falling asleep) was 1.93 ± 1.34 and preoperative cumulative ISI score (item1-7) was 18.67 ± 5.32. Preoperative AHI was 40.61 ± 12.02 (n/h) and preoperative ODI was 38.72 ± 14.28 (n/h). In the second follow-up, the mean difference in AHI was ∆ 10.47 ± 15.38 (n/h) and the mean difference in ODI was ∆ 8.17 ± 15.67 (n/h). Strong significant correlations were observed between ISI item 1 (difficulty falling asleep) and both ∆ AHI (r: −0.65, p=0.004) and ∆ ODI (r: −0.7; p=0.001) in the second follow-up.

Conclusion

Difficulty falling asleep may hence negatively influence HGNS therapeutic outcome. Insomnia-related symptoms should be considered in the preoperative patient evaluation for HGNS.

Keywords:

• hypoglossal nerve stimulation
• obstructive sleep apnea
• insomnia
• polysomnography

Abbreviations

COMISA, coexistence of insomnia and obstructive sleep apnea; OSA, obstructive sleep apnea;

HGNS, hypoglossal nerve stimulation; CPAP, continuous positive airway pressure; PAP, positive airway pressure; PSG, polysomnography; ISI, insomnia severity index; AHI, apnea–hypopnea index; BMI, body mass index; DISE, drug-induced sleep endoscopy; ODI, oxygen desaturation index (n/h).

Ethics Approval and Consent to Participate

All patients provided informed consent to the use of their data for research purposes. The data were evaluated in a pseudonymized fashion. Only health data that are collected in the clinical routine were analyzed retrospectively. So-called “third parties” did not have access to the data and publication occurs exclusively in anonymized form. The Ethics Committee of the Rhineland-Palatinate Medical Association refrains from providing advice in such cases, citing the State Hospital Act (§36 and §37) (see also: https://www.laek-rlp.de/ausschuesse-kommissionen/ethikkommission/).

Data Sharing Statement

The data underlying this article cannot be shared publicly for the privacy of individuals that participated in the study. The data will be shared on reasonable request to the corresponding authors.

Disclosure

H.G. reports research grants by Inspire Medical Systems, Inc. (MN, USA) that are unrelated to this study. The other authors have no conflicts of interest to declare in this work.

Additional information

Funding

No funding was received for this study.