Are measurements of real-world clinical outcomes other than the apnea-hypopnea index (AHI) useful in managing obstructive sleep apnea (OSA)?
Background: The gold standard assessment for OSA is polysomnography (PSG). During PSG, the frequency of obstructive events is reported as the AHI, and surgical treatment effectiveness for OSA is almost exclusively based on reported AHI changes; however, there is a disconnect between the levels of AHI used to denote outcomes of therapy and real-world clinical outcomes such as quality of life (QOL), patient perception of disease, cardiovascular measures, or survival.
Explore this issue:January 2014
Study design: Systematic review of 21 cohort and review studies from 1997 to 2012.
Setting: PubMed database.
Synopsis: For QOL measurements, scores in both general and disease-specific measures were different in patients with OSA compared to controls. QOL scores are responsive to OSA treatment, although there was no strong evidence linking general QOL measurements to AHI. For sleepiness measures, the Epworth Sleepiness Scale (ESS) shows a strong response to OSA intervention in general, but when compared to AHI, the correlation found no relation. For performance measurements, the motor vehicle collisions rate appears to correlate with AHI, while the Psychomotor Vigilance Test is reliable when performed under controlled conditions by experienced raters. For biological measurements, blood pressure correlates well with OSA outcomes, especially in the more severe disease state. Limitations include a dependence on the quality of published trials, the use of different gradations of measures of effect between studies and a lack of articles from surgical trials.
Bottom line: The literature shows a range of tools, based on symptoms and physiology of OSA that can assess effects of OSA treatment.
Citation: Tam S, Woodson T, Rotenberg B. Outcome measurements in obstructive sleep apnea: beyond the apnea-hypopnea index. Laryngoscope. 2014;124:337-343.