0648 Does Time Matter? The Association of Time between the Diagnostic Sleep Study and Hypoglossal Nerve Stimulator (HNS) Implant on AHI Reduction

Abstract Introduction The impact of the time between diagnostic study and hypoglossal nerve stimulator (HNS) implantation on treatment success has not been reviewed. Various determinants, including provider preference and insurance approval guidelines, require a baseline sleep study within two years of consultation for HNS. Our study evaluates whether the time elapsed between the diagnostic sleep study and HNS implantation can be used as a metric to predict treatment success. Methods A random cohort of patients who underwent HNS implantation at a single institution between 2022 and 2024 was identified from retrospective chart review. Treatment success was defined as an AHI reduction of >/=50% from baseline. The impact of the time between diagnostic study and implantation on treatment success was the primary outcome assessed. A two-sample t-test was used to evaluate differences in continuous variables between the group with successful treatment and unsuccessful treatment. Results 46 patients were identified from chart review for preliminary analysis of which only 33 patients with pre- and post implantation studies were included in the final statistical analyses. Average age (years) = 62±9.11, %male = 84.4(n=27), BMI= 31.31±3.98 Kg/m2, and pre-implantation AHI-4%= 33.75±18.87/hr. Average time from diagnostic study to implant was 372.12±304.32 days, with post-implantation AHI-4%=17.12±23.91. 54.55% (n=18) had treatment success. The time between diagnostic sleep study and implantation was 345.61±337.07 days in the treatment success group and 403±267.84 in the treatment failure group (P = 0.590). The average baseline AHI-4% in the treatment success group was 26.8±8.96, and the treatment failure group 37.62 ± 20.7 (P = 0.076). Conclusion Our study does not demonstrate any significant correlation between the time from diagnostic study to implantation on treatment success with HNS. This raises a question as to the rationale in repeating a diagnostic sleep study within 2 years of HNS implantation in those patients whose baseline study predates this. Centers for Medicare and Medicaid Services (CMS) continue to use this cutoff in the Local Coverage Determination (LCD) for HNS implant. Limitations of the data include lack of power of study. Additionally, this data has identified scope for improvement of post implantation sleep testing. Support (if any)