Improving the identification and triage of patients with Obstructive Sleep Apnea who require treatment: The Merlin tool for high risk populations

Questionnaires are routinely used to screen specific populations for obstructive sleep apnea. These questionnaires depend on subjective questions. The aim of the study was to identify verifiable and independently measurable risk factors and increase specificity to limit the number of polysomnography(PSG) evaluations and lower healthcare cost. Methods: A retrospective data collection of patients (N=164) enrolled for PSG was performed. OSA was defined as an AHIu003e=15 obtained from an overnight PSG. Sensitivity and specificity of each questionnaire as well as for combinations of other, independently verifiable factors (IVF) was calculated. A new questionnaire was devised including the IVFs and data was prospectively collected from patients undergoing PSG (N=209). Results: The retrospective analysis identified the most influential factors. Prospective data collection was performed, and analysis resulted in a new scale we called the Merlin Score. For every 100 patients with OSA, the total number enrolled for PSG based on each screening tool were respectively for STOP 92 enrolled of whom 41 were diagnosed and 1 patient missed, for STOP-Bang 94 enrolled, 42 identified and 1 missed, Berlin 83 enrolled, 36 identified and 7 missed, Epworth 46 enrolled, 22 identified and 20 missed and our new screening tool 65 enrolled, 35 identified and 8 missed. Conclusions: In a high-risk population of patients referred for PSG we identified independently verifiable factors associated with OSA with an AHI u003e15 and with only 2/3 of patients enrolled for PSG, we identified most OSA cases while keeping the number of missed cases down.