Decreased nocturnal glucose variability in non-diabetic patients with sleep apnea: a pilot study.

BACKGROUND Obstructive sleep apnea has been sho be associated with impaired glucose metabolism and overt diabetes mellitus. However, the effect of hypoxic episodes on nocturnal glucose regulation in non-diabetic patients is unknown. OBJECTIVES To investigate the effect of hypoxemia and nocturnal glucose homeosatsis in non-diabetic patients with sleep apnea. METHODS Seven non-diabetic patients with moderate to severe sleep apnea were connected to a continuous glucose-monitoring sensor while undergoing overnight polysomnography. Mean SpO2 and percentage of time spent at SpO2 90% were recorded. The correlation between mean glucose levels, the difference between consecutive mean glucose measurements (glucose variability) and the corresponding oxygen saturation variables were determined in each patient during REM and non-REM sleep. RESULTS No consistent correlation was found forthe individual patient between oxygen saturation variables and glucose levels during sleep. However, a lower mean SpO2 correlated with decreased glucose variability during sleep (r = 0.79, P = 0.034). This effect was primarily evident during REM sleep in patients with significant, compared to those with mild, oxygen desaturations during sleep (> 30% vs. < 10% of sleeping tim spent with SpO2 < 90%) (P = 0.03). CONCLUSIONS Severe nocturnal hypoxemia in non-diabetic patients with moderate to severe sleep apnea might affect glucose regulation primarily during REM sleep.