Effect of CPAP on blood glucose fluctuation in patients with type 2 diabetes mellitus and obstructive sleep apnea

Abstract

Purpose: This study aimed to investigate the effect of continuous positive airway pressure (CPAP) on blood glucose fluctuation in patients with type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA).

Methods: Patients with T2DM and OSA were divided into an intervention group and a control group. All patients were treatment naïve. The intervention group was given CPAP therapy. The subjects were monitored using a continuous glucose monitoring system (CGMS) for 2 weeks.

Results: Of 60 patients, 30 were selected to receive CPAP intervention while 30 without CPAP served as controls. The CPAP tolerance of the intervention group was good, with average time on CPAP therapy of 55.2 ± 4.3 days, and average daily time on CPAP therapy of 8.3 ± 2.8 h. The postprandial blood glucose (PBG), fasting blood glucose (FBG), and HbA1c levels in the intervention group decreased significantly (P < 0.05). Significant variations in 24-h mean blood glucose and night-time mean blood glucose were significantly lower with CPAP therapy than without therapy (P < 0.05, respectively). The mean of daily differences and mean ambulatory glucose excursions were both considerably lower with treatment than without (P < 0.05, respectively). There was also a significant difference in time in range and time above range (P < 0.05, respectively).

Conclusion: CPAP treatment may significantly improve the blood glucose level and blood glucose stability in patients with T2DM and OSA. CPAP is an effective treatment method beyond lifestyle intervention and drug therapy.

Keywords: Continuous glucose monitoring system; Continuous positive airway pressure; Obstructive sleep apnea; Type 2 diabetes mellitus.

Fig. 1

Comparison of laboratory indexes between intervention group and control group before and after treatment. There are no significant differences in LDL-C, TG, HDL-C, and TC, between the three groups. The level of HbA1c, PBG, and FBG reduced significantly compared with before in the intervention group (P < 0.05). In the control group, however, there were no significant differences in HbA1c, FBG, or PBG when compared to baseline (P > 0.05)

Fig. 2

Comparison of blood glucose fluctuation indexes between intervention group and control group before and after treatment. The levels of TIR¹, TAR¹, TBR¹, TIR², TAR², and TBR² did not differ significantly between the control group and the intervention group before treatment (P > 0.05). The level of TIR¹ and TAR¹ were lower than those before treatment in the intervention group (P < 0.05)