Adding SGLT inhibitors or metformin to insulin therapy for patients with type 1 diabetes

This study compared the effectiveness of adding sodium-glucose co-transporter (SGLT) inhibitors versus metformin (Glucophage) to insulin therapy for type 1 diabetes (T1D). This study concluded that SGLT inhibitors improved blood glucose control and weight loss better than metformin in these patients.

The goal of T1D management is to reach and maintain normal glucose levels. Typically, this is achieved through insulin injections. However, high doses of insulin may be associated with hypoglycemia (low blood sugar) and weight gain, making long-term management difficult.

Sodium-glucose cotransporter (SGLT) inhibitors added to insulin therapy may help improve blood glucose control for patients with T1D. These inhibitors lower blood glucose levels by preventing glucose reabsorption. SGLT inhibitors have been shown to improve blood sugar and body weight in patients with type 2 diabetes (T2D). Another medication that can be added to insulin therapy in patients with T1D is metformin. This drug helps the cells respond better to insulin. Whether SGLT inhibitors are more effective than metformin in patients with T1D is unclear.

This study included the results of nine clinical trials that had a total of 6,780 patients with T1D. All patients were on insulin therapy. In addition to insulin, patients received either metformin or an SGLT inhibitor such as dapagliflozin (Forxiga), sotagliflozin (Zynquista), or empagliflozin (Jardiance). Treatment ranged from 24 weeks to 3 years.

After 26 weeks of treatment, patients who received SGLT inhibitors had larger reductions in HbA1c (average blood glucose over the past three months) compared to the metformin group. Reductions in HbA1c levels ranged from 0.16% to 0.38% compared to metformin. After 52 weeks of treatment, HbA1c levels decreased even further, ranging from 0.23% to 0.34% compared to metformin.

After 26 weeks of treatment, patients who received SGLT inhibitors had larger reductions in weight compared to the metformin group. 

Patients who received metformin were more likely to stop treatment. After 52 weeks of treatment, sotagliflozin was associated with a 65% lower risk of low blood sugar compared to metformin.

This study concluded that SGLT inhibitors plus insulin improved blood glucose control and weight loss better than metformin plus insulin for patients with T1D. 

This study looked back in time to analyze data. These results are based on indirect evidence. More studies are needed to confirm these results.