Impact of the timing of drug-induced sleep endoscopy on the apnea-hypopnea index during polysomnography

Background: In addition to clinical examination, surgical decision making in obstructive sleep apnea (OSA) mainly depends on drug-induced sleep endoscopy (DISE) and polysomnography (PSG). Therefore, DISE is often performed the same day as PSG. The drugs used and the setting of DISE could have an impact on the severity of OSA during PSG and thus influence our therapy recommendation.Objectives: Is the severity of OSA in PSG different if DISE is performed the same day as PSG or independently of PSG?Methods: A retrospective cohort study of 101 patients out of a pool of 813 patients for MISE and PSG between 2017 and 2020 with previously polygraphically or polysomnographically confirmed OSA (Night 1), 24 of whom were surveyed externally and 77 in domo. In the study group (SG, n = 53) DISE was performed the same day as PSG (Night 2 ), whereas it was performed on a different day in the control group (KG, n = 58). The primary outcome measure was the change of the apnea-hypopnea index (AHI) between night 1 and night 2.Results: Between the two nights the mean and median AHI decreased by -4.77 +/- 18.92/h and -3.80/h in the SG versus -1.70 +/- 13.77/h and -0.25/h in the KG, respectively. However, statistical significance was only achieved when considering the data collected exclusively in domo (n = 77; p = 0.0189). There, the mean and median AHI remained unchanged in the KG, whereas it dropped significantly in the SG (mean: SG -7.62 +/- 20.47, KG 0.38 +/- 11.53; median: SG -6.65, KG 0.20).Conclusion: Performing DISE on the day of PSG may lead to a reduced AHI and thus influence the therapy recommendation, in particular if AHI limits have to be respected. This would suggest that DISE and PSG should be carried out on different days.