Apnea-hypopnea index: time to wake up

Area of Science:

• Sleep Medicine
• Respiratory Physiology
• Biostatistics

Background:

• The apnea-hypopnea index (AHI) is a common metric in sleep research.
• Its statistical properties and scientific validity have not been rigorously evaluated.
• Understanding the AHI's nature is crucial for accurate sleep-disordered breathing research.

Purpose of the Study:

• To critically examine the scientific and statistical properties of the apnea-hypopnea index.
• To evaluate the appropriateness of the AHI as a dependent or independent variable in sleep research.
• To provide recommendations regarding the use of the AHI in scientific investigations.

Main Methods:

• Conceptual analysis of the apnea-hypopnea index as a rate and a ratio.
• Review of statistical modeling approaches for sleep-disordered breathing.
• Evaluation of the AHI's suitability for representing exposure to sleep-disordered breathing.

Main Results:

• The apnea-hypopnea index can be interpreted as a rate (events per hour) but requires clear definition of the measured physical property.
• The AHI is seldom the preferred independent variable for modeling sleep-disordered breathing exposure.
• Statistical limitations exist when using the AHI in its current form.

Conclusions:

• The indiscriminate use of the apnea-hypopnea index in sleep research should be discouraged.
• Researchers must carefully consider the statistical properties of the AHI before its application.
• Alternative or refined metrics may be necessary for accurate assessment of sleep-disordered breathing.