The Relationship Between Hypoglossal Nerve Stimulation Levels and Apnea Hypopnea Index Percent Reduction.

OBJECTIVES: To identify predictors of hypoglossal nerve stimulation therapy success and examine the relationship between stimulation level and AHI reduction. METHODS: A retrospective chart review was conducted among adult OSA patients who received HNS surgery. Outcomes were determined based on AHI percentage reduction from baseline and success based on 50% reduction in AHI or greater (AHI50%), Sher15 (AHI percentage reduction ≥ 50% to a therapy AHI of ≤ 15 events/h) and Sher20 (AHI percentage reduction ≥ 50% to a therapy AHI of ≤ 20 events/h) criteria. RESULTS: A total of 85 HNS patients had mean AHI percentage reduction of 70.1%. Further, 75.3% of patients (n = 64) achieved an AHI percentage reduction ≥ 50%, 74.1% (n = 63) met Sher20 criteria, and 64.7% (n = 56) met Sher15 criteria. Patients who achieved an AHI50% had a significantly lower BMI (p < 0.01), lower treatment stimulation levels (p < 0.05), and lesser stimulation level changes from baseline (p < 0.05). In a multivariate binomial regression for AHI percentage reduction, BMI and stimulation level change were negatively associated with AHI percentage reduction, and preoperative AHI was positively associated, while age and sex were not significant predictors. CONCLUSION: BMI and treatment stimulation level change were significant negative predictors of HNS therapeutic success based on AHI percentage reduction. Patients who met AHI50% had lower treatment stimulation levels than those who did not achieve AHI50%. Those who had persistent OSA symptoms likely underwent continued uptitration in stimulation levels. The relationship between HNS stimulation level and therapeutic outcomes in HNS therapy requires further examination.