Strategically Playing with Fire: SGLT Inhibitors as Possible Adjunct to Closed-Loop Insulin Therapy

As closed-loop insulin therapies emerge into clinical practice and evolve in medical research for type 1 diabetes (T1D) treatment, the limitations in these therapies become more evident. These gaps include unachieved target levels of glycated hemoglobin in some patients, postprandial hyperglycemia, the ongoing need for carbohydrate counting, and the lack of non-glycemic benefits (such as prevention of metabolic syndrome and complications). Multiple adjunct therapies have been examined to improve closed-loop systems, yet none have become a staple. Sodium-glucose-linked cotransporter inhibitors (SGLTi's) have been extensively researched in T1D, with average reductions in placebo-adjusted HbA1c by 0.39%, and total daily dose by approximately 10%. Unfortunately, many trials revealed an increased risk of diabetic ketoacidosis, as high as 5 times the relative risk compared to placebo. This narrative review discusses the proven benefits and risks of SGLTi in patients with T1D with routine therapy, what has been studied thus far in closed-loop therapy in combination with SGLTi, the potential benefits of SGLTi use to closed-loop systems, and what is required going forward to improve the benefit to risk ratio in these insulin systems.

Sustained Intensive Treatment and Long-term Effects on HbA1c Reduction (SILVER Study) by CGM in People With Type 1 Diabetes Treated With MDI

OBJECTIVE

Continuous glucose monitoring (CGM) reduces HbA_1c and time spent in hypoglycemia in people with type 1 diabetes (T1D) treated with multiple daily insulin injections (MDI) when evaluated over shorter time periods. It is unclear to what extent CGM improves and helps to maintain glucose control, treatment satisfaction, diabetes distress, hypoglycemic concerns, and overall well-being over longer periods of time.

RESEARCH DESIGN AND METHODS

The GOLD trial was a randomized crossover trial performed over 16 months of CGM treatment in people with T1D treated with MDI. People completing the trial (n = 141) were invited to participate in the current SILVER extension study in which 107 patients continued CGM treatment over 1 year along with the support of a diabetes nurse every 3 months.

RESULTS

The primary end point of the change in HbA_1c over 1.0-1.5 years of CGM use compared with previous self-monitoring of blood glucose during GOLD showed a decrease in HbA_1c of 0.35% (95% CI 0.19-0.50, P < 0.001). Time spent in hypoglycemia <3.0 mmol/L (54 mg/dL) and <4.0 mmol/L (72 mg/dL) decreased from 2.1% to 0.6% (P < 0.001) and from 5.4% to 2.9% (P < 0.001), respectively. Overall well-being (World Health Organization 5-item well-being index, P = 0.009), treatment satisfaction (Diabetes Treatment Satisfaction Questionnaire, P < 0.001), and hypoglycemic confidence (P < 0.001) increased, while hypoglycemic fear (Hypoglycemia Fear Survey-Worry, P = 0.016) decreased and diabetes distress tended to decrease (Problem Areas in Diabetes Scale, P = 0.06). From randomization and screening in GOLD, HbA_1c was lowered by 0.45% (P < 0.001) and 0.68% (P < 0.001) after 2.3 and 2.5 years, respectively.

CONCLUSIONS

The SILVER study supports beneficial long-term effects from CGM on HbA_1c, hypoglycemia, treatment satisfaction, well-being, and hypoglycemic confidence in people with T1D managed with MDI.

Comparison of perioperative glucose regulation in patients with type 1 vs type 2 diabetes mellitus: A retrospective cross-sectional study

BACKGROUND

Most perioperative diabetes mellitus (DM) guidelines do not distinguish between patients with type 1 (DM1) and type 2 (DM2). We hypothesised that similar treatment of DM1 and DM2 patients leads to differences in their perioperative glucose control.

METHODS

We performed a retrospective cross-sectional study, of all DM patients undergoing surgery between May 2013 and November 2015 in a Dutch university hospital. We compared DM1 with DM2 patients, treated according to the same perioperative glucose protocol. Our primary outcome was the incidence of hyperglycaemia (glucose ≥10 mmol/L). Secondary outcomes were short-term glycaemic control (glucose before surgery and peak glucose perioperatively), long-term glycaemic control (HbA1c in 90 days before and after surgery) and the incidence of hypoglycaemia (glucose <4 mmol/L).

RESULTS

We included 2259 patients with DM, 216 (10%) of which had DM1. The calculated incidences in our population were 7 out of 1000 patients with DM1 and 69 out of 1000 patients with DM2. Compared to those with DM2, patients with DM1 were younger, had a lower BMI, a higher glucose concentration before surgery, and a higher perioperative peak glucose concentration (11.0 [8.2-14.7] vs 9.4 [7.7-11.7], P < 0.001). The incidence of the primary endpoint, perioperative hyperglycaemia, was significantly higher in DM1 compared to DM2 patients (63% vs 43%, P < 0.001). Hypoglycaemia occurred more often in the DM1 population (7.1% vs 1.3%, P < 0.001).

CONCLUSION

Providing similar perioperative treatment to patients with DM1 and DM2 is associated with poorer short-term and long-term glycaemic control in DM1 throughout the perioperative period as well as an increased risk of hypoglycaemia.