Effectiveness of treatment apnea-hypopnea index: a mathematical estimate of the true apnea-hypopnea index in the home setting.

PURPOSE: To present a new measurement instrument, the Effectiveness of Treatment Apnea-Hypopnea Index (ET-AHI), which the authors developed to determine an estimate of the therapeutic control of obstructive sleep apnea (OSA).
MATERIALS AND METHODS: The authors retrospectively evaluated a cohort of patients with OSA who initially attempted to use continuous positive airway pressure (CPAP) therapy and subsequently underwent maxillomandibular advancement (MMA) surgery. The ET-AHI calculations were performed to estimate the level of CPAP adherence that would be necessary to achieve equivalence with the MMA surgical result and to reach effective AHIs of 5 and 15.
RESULTS: The sample was composed of 37 adult patients (mean age, 44.2 ± 9.0 yr; 73% men) with moderate to severe OSA (baseline AHI, 56.3 ± 22.6). CPAP therapy was highly efficacious (CPAP titration AHI, 4.3 ± 5.9), but no patient could adequately adhere to treatment. MMA produced a significant decrease in OSA (AHI after MMA, 11.6 ± 7.4). The ET-AHI calculations predicted that an 86% adherence rate with CPAP would be necessary to achieve equivalence with MMA, whereas adherence rates of 99% and 79% may be required to achieve effective AHIs of 5 and 15, respectively.
CONCLUSIONS: The ET-AHI has the potential to significantly affect the care of patients with OSA because it may provide the treating clinician with a valuable tool to estimate the control of OSA for any therapeutic intervention. How closely the ET-AHI predicts the true effective AHI in the home setting requires further validation.