Inspire System Models 3024, 4063, 4323 English 37
200-079-101 Rev A
3024EN_ch.fm 5/6/14 10:31 pm
4.625 x 6 inches (117 mm x 152 mm)
Inspire Medical Confidential
Study Design and Methods
The STAR trial was a multicenter, prospective trial with a 12-month single arm study and a
randomized controlled therapy withdrawal study at 13 months. Following implant of the Inspire
system, patients were followed at 1, 2, 3, 6, 9, 12, 13, 15, 18 months, and every 6 months
thereafter. The patients' baseline AHI and ODI (oxygen desaturation index) values were the
mean results from their screening (pre-implant) and 1-month (post-implant but prior to therapy
activation) sleep studies. Baseline results were compared to the 12-month results to determine
the percentage of patients who experienced a clinically meaningful reduction in the severity of
their OSA in terms of their AHI and ODI scores. For this study, a clinically meaningful reduction
in AHI and ODI was defined as (1) a 50% reduction in the AHI compared to the pre-implant
screening and 1-month visit (post-implant but prior to therapy activation) and an AHI < 20 events
per hour, and (2) a 25% or greater reduction in ODI at the 12-month visit compared to baseline.
Upon completion of the overnight sleep study at the 12-month visit, a randomized controlled
therapy withdrawal study was conducted. The first 46 responders were randomized 1:1 to either
the therapy maintenance (ON) group or the therapy withdrawal (OFF) group, resulting in 23
subjects in each group. Patients randomized to the therapy withdrawal group had Inspire
therapy turned OFF for at least five days. Patients randomized to the therapy maintenance
group continued their use of the Inspire system. All randomized patients participated in a sleep
study at the 13-month visit. The therapy withdrawal group had the sleep study performed with
Inspire therapy OFF, and the therapy maintenance group had the sleep study performed with
the Inspire therapy ON. The mean change of AHI for each arm was compared to determine the
extent of treatment effect from Inspire therapy.
The percentage of sleep time a patient had an oxygen saturation (SaO
2
) level below 90% was
recorded during the sleep studies, and two validated quality of life questionnaires were
administered at follow-ups through 18 months. The quality of life questionnaire was the Epworth
Sleepiness Scale (ESS), which rates a patient's daytime sleepiness, and the Functional
Outcomes of Sleep Questionnaire (FOSQ), which assesses the effect of a patient's daytime
sleepiness on activities of ordinary living. The hypotheses for the secondary efficacy endpoints,
which included the randomized withdrawal study, FOSQ, ESS, and SaO2, were tested
according to a hierarchical strategy in order to preserve an overall Type I error rate of 5%.
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