Study Compares Continuous Insulin Infusions vs. Multiple Daily Injections for Glycemic Control in T1D

New data from a systematic review and meta-analysis of randomized controlled trials and real-world trials are providing insight into the comparative safety and efficacy ofreal-time continuous glucose monitoring(CGM) in conjunction with open loop-continuous subcutaneous insulin infusions versus conventional multiple daily injections in type 1 diabetes.

Results of the study suggest use of either approach resulted in similar effects on HbA1c, weight, insulin usage, and time-in-range, but also indicate an approach using continuous infusions was associated with greater costs and reduced quality of life compared to a strategy using multiple daily infusions.

“To the best of our knowledge, this is the first systematic review and meta-analysis comparing RT-CGM plus continuous subcutaneous insulin infusion vs RT-CGM plus multiple daily injections and its impact on glycemic control, in addition to other significant outcomes,” wrote investigators. “It is a recap of the last 22 years' novel interventions in the field of diabetes, since continuous glucose monitors FDA approval, looking at the impact of RT-CGM when combined with continuous subcutaneous insulin infusion as opposed to multiple daily injections in optimizing glycemic control in type 1 diabetes.”

Although the advent of CGM has transformed diabetes management in recent decades, investigators noted a lack of consensus to guide selection of appropriate insulin administration method among real-time CGM users. With this in mind, a team from Queen Margaret University and the Sligo University Hospital designed the current study as a systematic review and meta-analysis of all randomized controlled trials and real-world trials lasting longer than 6 months that compared CGM with continuous insulin infusions and CGM with multiple daily injections in patients with type 1 diabetes from the Cochrane, MEDLINE, Web of Science, Google Scholars, PubMed, Embase, and cited literature in articles published from 2010-2021.

From their keyword search, investigators identified 1541 reference documents and 104 additional articles from reference lists. After application of exclusion criteria, 3 studies were identified for inclusion. These studies had an overall sample size of 150 patients, with 78 receiving continuous subcutaneous insulin infusion and 72 receiving multiple daily infusions. The mean HBA1c in the continuous infusions group was 63.3±9.2 mmol/mol and 63.5±10.2 mmol/mol in the multiple daily injections group. Investigators noted the mean age of study participants was 37.1 years.

The primary outcome of interest was the impact of each strategy on HbA1c in patients with type 1 diabetes. Secondary outcomes of interest for the study included impact on BMI, insulin usage, time in range, time above range, time below range, cost-effectiveness, quality-adjusted life years, and more.

Upon analysis, results suggested there was no statistically significant reduction in HbA1c with use of continuous subcutaneous insulin infusions compared with multiple daily injections (P=.75). Similarly, there was no statistically significant differences observed for impact on time in range (P=.15), body weight (P=.75), and insulin usage (P=.20) with either strategy. Investigators pointed out there was an overall homogeneity observed among the 3 trials in respect to all previous variables with I² being 0%.

“The chief result of our meta-analysis is that RT-CGM in conjunction with open-loop continuous subcutaneous insulin infusions or multiple daily injections has a similar impact on the glycemic outcome, weight, insulin usage and TIR. In addition, RT-CGM when combined with open-loop continuous subcutaneous insulin infusions is not cost-effective withRT-CGM multiple daily injections being an equally effective alternative,” wrote investigators.

This study, “RT-CGM in conjunction with CSII vs MDI in optimizing glycaemic control in T1DM: Systemic review and meta-analysis,” was published in Endocrinology, Diabetes & Metabolism.