SGLT2 Inhibitors Better Protect Kidneys Than GLP-1 Receptor Agonists in Type 2 Diabetes

For individuals managing type 2 diabetes, the choice of medication can have far-reaching effects, extending beyond blood sugar control to include kidney health. Recent research suggests a notable difference in how two classes of drugs – SGLT2 inhibitors and GLP-1 receptor agonists – impact kidney function. A comprehensive study, published in JAMA Internal Medicine and reported by Le Quotidien du Médecin, indicates that initiating treatment with an SGLT2 inhibitor is associated with a lower risk of chronic kidney disease and acute kidney injury over a five-year period compared to treatment with a GLP-1 receptor agonist.

Understanding the Study and its Approach

The findings stem from an observational study utilizing Danish national data, encompassing individuals with type 2 diabetes treated with metformin who began either an SGLT2 inhibitor or a GLP-1 receptor agonist between January 2014 and November 2020. Researchers followed these patients until October 2024, tracking the incidence of acute and chronic kidney disease, as well as secondary outcomes like albuminuria (protein in the urine) and mortality. The study employed a targeted emulation trial design, a method used to mimic the conditions of a randomized controlled trial when such a trial isn’t feasible. This approach helps to strengthen the evidence base, though it’s vital to acknowledge the inherent limitations of observational studies.

The study included a substantial cohort: 36,279 patients initiating SGLT2 inhibitor treatment and 18,782 starting a GLP-1 receptor agonist. The average age was similar between the groups (63 years for the SGLT2 group versus 61 years for the GLP-1 group), and baseline characteristics were comparable, suggesting a reasonable balance between the two groups at the start of the study.

Key Findings: Reduced Risk with SGLT2 Inhibitors

After five years, the weighted risk of chronic kidney disease was 6.7% in the SGLT2 inhibitor group compared to 8.2% in the GLP-1 receptor agonist group. This translates to a 19% relative risk reduction (risk ratio of 0.81) and an absolute risk difference of -1.5%. Similarly, the incidence of acute kidney injury was also lower with SGLT2 inhibitors, with a relative risk of 0.88 and an absolute risk difference of -3.5 events per 100 patients over five years. You can find more details about the study methodology in the original publication: https://www.lequotidiendumedecin.fr/specialites/diabetologie-endocrinologie/doi:%2010.1001/jamainternmed.2025.7409.

It’s important to note that while SGLT2 inhibitors demonstrated a clear advantage in reducing kidney-related events, GLP-1 receptor agonists showed a slight reduction in albuminuria and mortality – though these differences were less pronounced. This suggests that both drug classes offer benefits, but through different mechanisms and with varying impacts on specific outcomes.

What Do SGLT2 Inhibitors and GLP-1 Receptor Agonists Actually Do?

Both SGLT2 inhibitors and GLP-1 receptor agonists are used to manage blood sugar in people with type 2 diabetes, but they work in different ways. SGLT2 inhibitors (like empagliflozin or dapagliflozin) work by blocking the reabsorption of glucose in the kidneys, causing excess sugar to be excreted in the urine. GLP-1 receptor agonists (like semaglutide or liraglutide) mimic the effects of a natural hormone that stimulates insulin release and slows down gastric emptying. The differing mechanisms likely explain the observed differences in kidney protection.

The Importance of Context: Who Benefits Most?

The study’s findings were consistent across various subgroups, but the most significant benefits of SGLT2 inhibitors – in terms of reducing chronic kidney disease and acute kidney injury – were observed in patients without pre-existing kidney disease. This suggests that SGLT2 inhibitors may be particularly valuable for the primary prevention of kidney disease in individuals newly diagnosed with type 2 diabetes. This is a crucial distinction, as it highlights the potential for these medications to protect kidney function before significant damage has occurred.

Observational Studies and the Demand for Further Research

While this study provides compelling evidence, it’s essential to remember that it is observational in nature. Which means that researchers observed associations between drug treatments and outcomes, but they did not randomly assign patients to receive one drug or the other. There is a possibility of confounding factors – other variables that could explain the observed differences. For example, differences in lifestyle, other medical conditions, or adherence to treatment could have influenced the results.

The Haute Autorité de Santé (HAS) in France also highlights the need to evaluate antecedents and risk of diabetic ketoacidosis when initiating glifozine treatment, emphasizing the importance of careful patient assessment. More information on this can be found here. Further research, ideally in the form of randomized controlled trials, is needed to confirm these findings and to fully understand the mechanisms underlying the observed differences in kidney protection.

Implications for Treatment Guidelines and Clinical Practice

The study’s authors argue that the robust data warrants a re-evaluation of current treatment guidelines. They point out that guidelines from organizations like the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) currently recommend both SGLT2 inhibitors and GLP-1 receptor agonists with similar emphasis for managing kidney disease in type 2 diabetes. This research suggests that SGLT2 inhibitors should be prioritized, particularly in patients without existing kidney problems.

This doesn’t mean GLP-1 receptor agonists are ineffective. They still offer valuable benefits for blood sugar control and may have advantages in other areas, such as cardiovascular health. However, when kidney protection is a primary concern, the evidence currently favors SGLT2 inhibitors.

What Does This Mean for Patients?

If you have type 2 diabetes, it’s crucial to discuss your individual risk factors and treatment options with your healthcare provider. This study underscores the importance of a personalized approach to diabetes management, taking into account not only blood sugar control but also kidney health. Don’t hesitate to request questions about the potential benefits and risks of different medications, and work with your doctor to develop a treatment plan that is right for you. The European Society of Cardiology also provides resources on managing diabetes and cardiovascular risk: https://www.escardio.org/guidelines-and-position-papers/guidelines.

As research continues to evolve, treatment recommendations may change. Staying informed and maintaining open communication with your healthcare team are essential for optimal diabetes care.