Outcome measurements in obstructive sleep apnea: beyond the apnea-hypopnea index

Objectives/hypothesis: The apnea-hypopnea index (AHI) is overwhelmingly used as the main therapeutic metric in the assessment of obstructive sleep apnea (OSA) in surgical studies. However, using AHI as the sole measure is problematic. This study investigates the utility of other outcome measures for patients with OSA undergoing surgery.

Study design: Systematic review of cohort and review studies.

Methods: A review was performed using the PubMed database. English articles focusing on outcome measures in adults with OSA were included. Studies in pediatric populations, those combining obstructing and central sleep apnea, and those without the use of outcome measures were excluded. Articles were categorized according to level of evidence. The Downs and Black scale and AMSTAR scale were used to assess quality.

Results: Of a total of 10,454 retrieved articles, 21 studies met inclusion and exclusion criteria. Most articles related to continuous positive airway pressure outcomes. Many categories of outcome measures were found: general quality of life, OSA-specific quality of life, measurements of sleepiness, performance, and physiological. Subjects with OSA scored differently in measurement tools in all categories compared to control populations or after treatment, and generally a poor correlation with AHI was seen.

Conclusions: The literature shows a range of tools based on symptoms and physiology of OSA that can assess effects of treatment. Assessment of surgical treatment for OSA should neither be limited to AHI as an outcome, nor should this be the only outcome stressed.