We sought to evaluate sleep measures that better predict incident diabetes and pre-diabetes in a large cohort of veterans.

This secondary analysis included 650 patients without baseline diabetes from a multisite observational veterans’ cohort. Participants underwent OSA evaluation via laboratory-based polysomnography between 2000-2004 with follow-up through 2012. The primary outcomes were pre-diabetes and diabetes defined by fasting blood glucose, hemoglobin A1c or use of glucose-lowering medication at study initiation. Exposure variables included respiratory event frequency, arousals, and oxygen desaturation. Cox models adjusted for BMI, age, race, sex, change in BMI, and continuous positive airway pressure (CPAP) device utilization.

The adjusted analysis revealed that time spent with oxygen saturation less than 90 (T90) (HR 1.009, CI 1.001-1.017, p=0.02), respiratory arousals (HR 1.009, CI 1.003-1.015, p=0) and total arousals (HR 1.006 CI 1.001 – 1.011 p = 0.02) were associated with an increased incidence of diabetes. Increases in mean nocturnal oxygen saturation were associated with decreased incidence of diabetes (HR 0.914 CI 0.857-0.975, P<0.01 and pre-diabetes (HR 0.914 CI 0.857-0.975, P<0.01). No significant relationships were demonstrated for AHI, measures related to central apnea, Cheyenne Stokes respiration, periodic limb movements, or Epworth Sleepiness Scale score.

There was no significant association of incident pre-diabetes or diabetes with AHI, the gold standard of sleep apnea severity. This study suggests that hypoxia may be a better predictor of glycemic outcomes than AHI in an OSA population and may provide clues to the underlying mechanism(s) that link sleep-disordered breathing and its metabolic consequences.