Summary: In a double-blind trial in type 2 diabetes inadequately controlled on metformin, empagliflozin produced the largest improvements in glucose, weight, lipids, and blood pressure across the three arms, with significant advantages over metformin, while sitagliptin gave intermediate glycaemic benefit.
PICO Summary
| Element | Detail |
|---|---|
| Population | Adults with type 2 diabetes inadequately controlled on metformin; double-blind RCT, Tabriz, Iran. |
| Intervention | Empagliflozin 10 mg daily added to metformin. |
| Comparison | Sitagliptin 100 mg daily, or metformin alone, over 12 weeks. |
| Outcome | HbA1c fell -1.8% (empagliflozin), -1.35% (sitagliptin), and -0.69% (metformin); fasting glucose -23.1, -16.15, -15.25 mg/dL respectively. Versus metformin, empagliflozin significantly improved HbA1c and fasting glucose (p=0.037, 0.027), weight (-4.1 vs -0.90 kg; p=0.044), triglycerides, HDL, and blood pressure (SBP -8.27, DBP -13.37 mmHg). |
Empagliflozin vs sitagliptin add-on
RCT · type 2 diabetes · 12 weeks
As add-on to metformin, empagliflozin lowered HbA1c more than sitagliptin (-1.8% vs -1.35%) and added weight and blood-pressure benefit. Significant differences were mainly versus metformin in this small 12-week trial.
Expert Commentary
This is a straightforward head-to-head that lands where mechanism predicts. As an add-on to metformin, empagliflozin delivered the broadest cardiometabolic package, larger HbA1c and fasting-glucose reductions, meaningful weight loss, and improvements in triglycerides, HDL, and blood pressure, whereas sitagliptin improved glucose modestly but, as expected for a DPP-4 inhibitor, did little for weight or pressure. None of that is surprising, but a clean randomised confirmation is still useful. I would read the specific comparisons carefully: the clearly significant differences reported are largely empagliflozin versus metformin, so the empagliflozin-over-sitagliptin margin, while numerically favouring empagliflozin, should be stated more cautiously than a direct superiority claim. The trial is also small, short at twelve weeks, and single-centre, and one blood-pressure figure looks unusually large, so I have reported it with its source value rather than smoothing it. Can I use this with my patients? Yes, in keeping with current practice. For a patient needing intensification beyond metformin, particularly with overweight, hypertension, or cardiovascular risk, it supports favouring an SGLT2 inhibitor over a DPP-4 inhibitor for the wider metabolic benefit, while counselling on genital mycotic infection risk.
References
Mesri Alamdari N, Barghaman M, Roshanravan N, et al. Comparison of the effects of empagliflozin and sitagliptin, as an add-on to metformin, on cardio-metabolic and glycemic parameters of patients with type 2 diabetes mellitus: a randomized, double-blind clinical trial. BMC Res Notes. 2025;18(1):339. doi:10.1186/s13104-025-07214-2