Reliable Calculation of the Efficacy of Non-Surgical and Surgical Treatment of Obstructive Sleep Apnea Revisited

Background: Various treatment methods exist to treat obstructive sleep apnea (OSA); continuous positive airway pressure (CPAP) is considered the gold standard. It is however a clinical reality that the use of CPAP is often cumbersome. CPAP treatment is considered compliant when used >= 4 h per night as an average over all nights observed. Surgery, on the other hand, is regarded as successful when the apnea hypopnea index (AHI) drops at least 50% and is reduced below 20/h postoperatively in patients whose preoperative AHI was > 20/h. The effectiveness of CPAP compliance criteria can be questioned, just as the effectiveness of surgical success criteria has often been questioned. Study Objectives: The aim of the study was to compare non optimal use of optimal therapy (CPAP) with the continuous effect (100%) of often non optimal therapy (surgery). Design: Using mathematical function formulas, the effect on the AHI of various treatment modalities and their respective compliance and success criteria were calculated. Results: The more severe the AHI, the more percentage of total sleep time (TST) CPAP must be used to significantly reduce the AHI. Patients with moderate OSA reduce the AHI by 33.3% to 48.3% when using CPAP 4 h/ night (AHI 0-5, respectively). The required nightly percentage use rises as one reduces the AHI target to <5. CPAP must be used 66.67% to 83.33% per night to reduce the AHI below 5 (AHI of 0 while using CPAP). Conclusions: Using a mean AHI in CPAP therapy is more realistic than using arbitrary compliance rates, which, in fact, hide insufficient reductions in AHI.