Effect of Glucose Improvement on Nocturnal Sleep Breathing Parameters in Patients with Type 2 Diabetes: The Candy Dreams Study

Abstract

Type 2 diabetes exerts a negative impact on sleep breathing. It is unknown whether a long-term improvement in glycemic control ameliorates this effect. We conducted an interventional study with 35 patients with type 2 diabetes and obstructive sleep apnea (OSA) to explore this. At home, sleep breathing parameters were assessed at baseline and after a 4-month period in which antidiabetic therapy was intensified. Patients who decreased their body mass index ≥2kg/m 2 were excluded. Those with an HbA1c reduction ≥0.5% were considered good responders (n = 24). After the follow-up, good responders exhibited an improvement in the apnea-hypopnea index (AHI: 26-1 (95% IC: 8.6-95.0) vs. 20.0 (4.0-62.4) events/hour, p = 0.002) and in time with oxygen saturation below 90% (CT90: 13.3 (0.4-69.0) vs. 8.1 (0.4-71.2) %, p = 0.002). No changes were observed in the group of non-responders (p = 0.722 and p = 0.138, respectively). The percentage of moderate and severe OSA decreased among good responders (p = 0.040). In the wider population, the change in HbA1c correlated positively to decreases in AHI (r = 0.358, p = 0.035) and negatively to increases in the minimum arterial oxygen saturation (r = −0.386, p = 0.039). Stepwise multivariate regression analysis showed that baseline AHI and the absolute change in HbA1c independently predicted decreased AHI (R 2 = 0.496). The improvement of glycemic control exerts beneficial effects on sleep breathing parameters in type 2 diabetes, which cannot be attributed merely to weight loss.

The Association Between Serum/Plasma Leptin Levels and Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

“…Studies in animal models have shown that leptin is a powerful stimulant of ventilation that can prevent respiratory depression in obese animals. There is accumulating evidence that leptin affects the contraction of the upper airway during sleep ( 66 ), suggesting that elevated leptin levels in the central nervous system may prevent the occurrence of OSAS. The increase in serum leptin levels in patients with OSAS may be a compensatory protective mechanism to prevent respiratory depression ( 67 ).…”

Endocrine disorders in obstructive sleep apnoea syndrome: A bidirectional relationship

“…Better results were obtained in patients treated by insulin alone. These interesting data need to be confirmed in further studies 71 …”

Prediabetes Is Associated with Increased Prevalence of Sleep-Disordered Breathing

“…Only one study has, so far, focused on weight loss intervention in subjects with both prediabetes and obstructive sleep apnea, showing that changes in SpO 2 were associated with changes in insulin sensitivity but not with weight loss [ 33 ]. Similarly, our group has demonstrated that in type 2 diabetes the improvement of metabolic control achieves a significant reduction in sleep breathing parameters not related with weigh modifications [ 6 ]. These results point out a direction for the further improvement of metabolic control in individuals with prediabetes.…”

“…The Sweet Sleep study characterized obstructive sleep apnea (OSA) in patients with type 2 diabetes, providing evidence that the composition of their apnea–hypopnea index (AHI) is characterized by an increase in apnea events, with no differences or even reduction in hypopnea episodes [ 2 ]. Additionally, a small interventional study with 35 patients with type 2 diabetes and OSA has recently shown how the improvement of glycemic control without significant weight loss exerts beneficial effects on sleep breathing parameters [ 6 ]. This multifaceted relationship between diabetes milieu and sleep breathing is based on several pathophysiological mechanisms that include insulin resistance, inflammatory and oxidative stress-activated signaling pathways, leptin resistance and abnormalities in the autonomic nervous system [ 1 , 7 ].…”