Normal and elevated HbA1C levels correlate with severity of hypoxemia in patients with obstructive sleep apnea and...

Area of Science:

• Sleep Medicine
• Endocrinology
• Cardiology

Background:

• Sleep apnea is linked to elevated HbA1C in diabetic and non-diabetic individuals.
• The relationship between sleep apnea severity and HbA1C across a spectrum of glycemic levels remains less understood.
• The impact of continuous positive airway pressure (CPAP) on HbA1C in sleep apnea patients is debated.

Purpose of the Study:

• To investigate the correlation between sleep apnea severity and HbA1C levels.
• To evaluate the effect of CPAP treatment on HbA1C in patients with severe sleep apnea.

Main Methods:

• Thirty patients with obstructive sleep apnea (OSA) without prior diabetes diagnosis were enrolled.
• Patients underwent polysomnography and HbA1C measurement, categorized into three groups based on HbA1C (<6%, 6-6.5%, ≥6.5%).
• Twelve patients with severe OSA received CPAP treatment for 3-5 months, with repeat polysomnography and HbA1C determination.

Main Results:

• HbA1C levels correlated significantly with hypoxemia severity (average SpO2, r=-0.43, p=0.019; % time with SpO2 <90%, r=0.48, p=0.007).
• In severe OSA patients, CPAP treatment led to a decrease in mean HbA1C from 6.47±0.67% to 6.28±0.51% (p=0.038).

Conclusions:

• Sleep apnea severity, indicated by hypoxemia, is associated with HbA1C levels from normal to diabetic ranges.
• CPAP therapy over 3-5 months effectively lowers HbA1C in patients suffering from severe sleep apnea.