Injectable Insulin and GLP-1 Combination Therapies for Diabetes: What's Available and How They Compare

What the researchers found

Nine types of injectable combination therapies (ICTs) are currently available for diabetes, including combinations of conventional human insulin, insulin analogs, insulin coformulations, and insulin/GLP-1 receptor agonist combinations. Meta-analysis data showed no significant differences in HbA1c reduction, hypoglycemia, weight change, or daily insulin dose between ICTs and basal-bolus regimens. ICTs are recommended by all international guidelines for treatment intensification, offering reduced daily needle-prick count and improved long-term compliance.

Why it matters

Managing type 2 diabetes often requires multiple daily injections, which creates a significant barrier to treatment adherence — especially in countries like India with enormous diabetes populations. Injectable combination therapies simplify regimens by combining insulin and/or GLP-1 receptor agonists into fewer injections, achieving equivalent glycemic control with better convenience and compliance.

How the study worked

Literature review searching PubMed, Medline, and Embase for articles published through July 2019 using MeSH terms and keywords for insulin, GLP-1 analogues, and combination therapy. The review synthesizes evidence from clinical trials, meta-analyses, and international guidelines, with particular focus on the Indian clinical context.

Who was studied

Patients with type 2 diabetes requiring treatment intensification beyond basal insulin, with focus on the Indian clinical context

What this study cannot tell us

The literature search only extends to July 2019, missing more recent combination therapy approvals and trial data. The Indian perspective may not fully generalize to other healthcare systems with different cost structures and drug availability. As a narrative review, the article does not apply systematic review methodology. Specific meta-analysis numbers and forest plots are not detailed in the abstract.

How to read the evidence

This is a narrative review that draws on meta-analysis data and international guidelines. While the underlying evidence includes randomized controlled trials, the review itself is not a systematic review and provides an expert opinion perspective rather than a rigorous evidence synthesis.

When this study was published

Published in 2020 with a literature search through July 2019. Since then, additional insulin/GLP-1 RA combinations have gained regulatory approvals and more real-world data has accumulated, though the core findings about equivalence to basal-bolus regimens remain valid.

The bigger picture

India has one of the world's largest diabetes populations, and treatment adherence is a persistent challenge due to complex injection regimens, cost, and needle fatigue. Injectable combination therapies represent an important step toward simplifying diabetes management globally. As newer insulin/GLP-1 RA combinations continue to be developed, they may help bridge the gap between guideline-recommended treatment and real-world patient compliance.

Questions still open

• How do the costs of injectable combination therapies compare to separate insulin and GLP-1 RA injections in the Indian healthcare market?
• Do the newer insulin/GLP-1 RA combinations (like iDegLira and iGlarLixi) offer advantages over premixed insulin combinations in real-world Indian populations?
• Can simplification of injection regimens measurably improve long-term diabetes outcomes and reduce complications in low- and middle-income countries?

Common questions

Read the original research

Injectable combination therapies for the management of diabetes: an Indian perspective.

Expert opinion on drug metabolism & toxicology, 16(3), 209-216

Citation

Dutta, Deep; Khandelwal, Deepak; Kalra, Sanjay. (2020). Injectable combination therapies for the management of diabetes: an Indian perspective.. Expert opinion on drug metabolism & toxicology, 16(3), 209-216. https://doi.org/10.1080/17425255.2020.1735351