Adherence and Persistence Among Individuals Living With Type 2 Diabetes and Using a Free Combination of Basal Insulin and an Injectable Glucagon-Like Peptide-1 Receptor Agonist Versus a Fixed-Ratio Combination Therapy: A Japanese Database Study.
Japanese researchers just dropped some clarity on adherence in type 2 diabetes research. They looked at adults using a free combination of basal insulin and injectable GLP-1 receptor agonists (that’s a mouthful, but it means two separate shots) versus a fixed-ratio combination therapy (FRC, both compounds in one injection). The team pulled data from a massive claims database, tracking over 4,000 people for a full year.
Diabetes Obes Metab
by Miyatsuka T, Brash J, Davies E et al.
“Adherence and Persistence Among Individuals Living With Type 2 Diabetes and Using a Free Combination of Basal Insulin and an Injectable Glucagon-Like Peptide-1 Receptor Agonist Versus a Fixed-Ratio Combination Therapy: A Japanese Database Study. Miyatsuka T(1), Brash J(2), Davies E(2), de Laguiche E(3), Vistisen D(3), Yin C(2), Adam A(2). Author information: (1)Department of Diabetes, Endocrinology and Metabolism, Kitasato University School of Medicine, Sagamihara, Japan. (2)IQVIA Inc, London, UK. (3)Novo Nordisk A/S, Søborg, Denmark. AIM: To investigate adherence to and persistence with free combination therapy (daily basal insulin plus an injectable glucagon-like peptide-1 receptor agonist [GLP-1 RA]) versus fixed-ratio combination (FRC) therapy (basal insulin plus a GLP-1 RA) among individuals with type 2 diabetes (T2D) in Japan. MATERIALS AND METHODS: This retrospective, observational cohort study used DeSC-IQVIA Integrated claims data from Japan to identify adults (aged ≥ 18 years) with confirmed T2D and ≥ 1 prescription for a GLP-1 RA (with predefined basal insulin persistence window) or an FRC during October 2019 to September 2023. Study index was date of first GLP-1 RA or FRC prescription; follow-up was 365 days. The primary objective was to evaluate adherence to and persistence with free combination therapy versus FRC therapy. RESULTS: Age (mean [standard deviation]) at index was statistically significantly higher in the free combination group (67.0 [13.85] years, n = 2063) than in the FRC group (65.7 [13.85] years, n = 2386) (p = 0.002). Odds of optimal adherence at end of follow-up were statistically significantly higher with FRC therapy than with free combination therapy (adjusted odds ratio [95% confidence interval]: 1.96 [1.73-2.23]; p < 0.001). Risk of discontinuation by end of follow-up was statistically significantly lower with FRC therapy than with free combination therapy (adjusted hazard ratio [95% confidence interval]: 0.66 [0.61-0.71]; p < 0.001). Adherence and persistence findings were similar in elderly individuals. CONCLUSIONS: In this real-world, adult population with T2D in Japan, FRC therapy was associated with improved adherence and persistence versus free combination therapy. © 2026 The Author(s). Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.”
Here’s what matters: people using the fixed-ratio combo stuck with their therapy more often and took their doses more reliably. The odds of optimal adherence were almost double in the FRC group compared to the free-combo group. Discontinuation rates told a similar story—people were about one-third less likely to drop off FRC therapy. This pattern held up even in older participants.
Key takeaways for peptide researchers:
Fixed-ratio GLP-1 RA and basal insulin combos boost adherence and persistence in real-world data.
Managing multiple, separate injections is still a hurdle for many, even in a motivated patient pool.
Simplifying peptide protocols could drive better research outcomes, not just in diabetes but across other peptide-based studies.
The study didn’t dive into the reasons, but let’s be real: less hassle means more consistency. For anyone designing peptide research protocols, these findings are a nudge to think about delivery methods and participant experience.
Looking for more insights or sourcing options? Check out the peptide research index or browse our vendor directory for trusted suppliers.
Bottom line: streamlined peptide delivery isn’t just convenient—it’s a proven advantage for adherence in research settings.
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