The effect of continuous positive airway pressure on glucose excursions in diabetics with sleep-disordered breathing: the results of continuous glucose monitoring

Abstract

WINNING ABSTRACT: Sleep-disordered breathing (SDB) is often associated with impaired glucose metabolism. The study aimed at assessing immediate effect of CPAP on glucose excursions in type 2 diabetic patients with SDB measured with 72hour continuous glucose monitoring system (CGMS). 8 type 2 diabetic patients with SDB (men, age 48,13i4,91 years, BMI 34,06i7,41 kg?m -2 , HbA1c 7,3i1,4%) underwent 2 overnight polysomnographic examinations including diagnostic night and CPAP night. CGMS was applied on both occasions. Statistical analyses included paired Student’s t-test. CPAP decreased apnoea-hypopnoea index (AHI) from 57,64i9,64?h -1 to 8,05i4,42?h -1 (p,0,0001) with significant improvement of saturation. Frequent episodes of sleep apnoea/hypopnoea and severe oxygen desaturation were followed by significant rise in blood glucose of up to 12,3 mmol?l -1 . Duration of post-hypoxic hyperglycemia was 50i10,79 min and its climax tended to be appeared up to 45min post-hypoxia. Nocturnal hyperglycemia strongly correlated with severe oxygen desaturation. Nocturnal glucose values were significantly higher during diagnostic night than during CPAP night (8,19i0,99 mmol?l -1 versus 6,77i1,47 mmol?l -1 ;p ,0,0001). CGMS also showed improved preprandial and 1,5-hour postprandial glucose levels for breakfast after CPAP night. The improvement in overall glucose levels was much greater in patients with BMI,30 kg?m -2 than in more obese patients. The results suggest that nocturnal hyperglycemia is closely related to desaturation and CPAP treatment may have an immediate decreasing effect on blood glucose in type 2 diabetic patients with SDB.