Jardiance vs Farxiga: Real-World Evidence Comparison

What Do the Landmark Cardiovascular Outcome Trials Show?

The cardiovascular outcome trial (CVOT) data for these two drugs tell somewhat different stories, even though both proved superior to placebo on their primary endpoints. Understanding those differences is the clearest starting point for any head-to-head clinical comparison.

EMPA-REG OUTCOME: Empagliflozin's Mortality Signal

EMPA-REG OUTCOME enrolled 7,020 adults with type 2 diabetes and established cardiovascular disease and followed them for a median of 3.1 years [1]. The primary three-point MACE endpoint (CV death, non-fatal myocardial infarction, non-fatal stroke) was reduced by 14% relative to placebo (HR 0.86, 95% CI 0.74 to 0.99, P<0.001 for non-inferiority and P=0.04 for superiority) [1].

The mortality signal was striking. CV death fell by 38% (HR 0.62, 95% CI 0.49 to 0.77, P<0.001), and all-cause mortality fell by 32% (HR 0.68, 95% CI 0.57 to 0.82, P<0.001) [1]. Hospitalisation for heart failure dropped by 35% [1]. These results, published in the New England Journal of Medicine in 2015, drove early guideline preference for empagliflozin in patients with established atherosclerotic cardiovascular disease (ASCVD).

DECLARE-TIMI 58: Dapagliflozin in a Broader Population

DECLARE-TIMI 58 enrolled 17,160 adults with type 2 diabetes, roughly half of whom had established ASCVD and the other half only multiple risk factors [2]. The trial met its non-inferiority endpoint on MACE (HR 0.93, 95% CI 0.84 to 1.03) but did not achieve superiority for MACE reduction [2].

Dapagliflozin did significantly reduce the composite of CV death or hospitalisation for heart failure by 17% (HR 0.83, 95% CI 0.73 to 0.95, P=0.005), driven primarily by the hospitalisation for heart failure component [2]. In patients with reduced ejection fraction at baseline, CV death or worsening heart failure was cut by 38% [2]. The broader, lower-risk enrollment population in DECLARE partly explains why the MACE signal was weaker than in EMPA-REG.

What the Trial Designs Mean for Your Patient

Neither trial was a direct head-to-head study. EMPA-REG enrolled a higher-risk population, which amplifies absolute risk reductions. A patient who matches the EMPA-REG profile, meaning established ASCVD with prior MI or coronary artery disease, has the strongest evidence base for empagliflozin. A patient whose primary concern is heart failure prevention across a wider risk spectrum fits closer to the DECLARE-TIMI 58 design.

Heart Failure Indications: Where Farxiga and Jardiance Now Diverge

Both drugs carry FDA-approved heart failure indications, but the approved phenotypes differ in ways that matter clinically.

DAPA-HF and the HFrEF Indication for Farxiga

DAPA-HF enrolled 4,744 patients with heart failure with reduced ejection fraction (HFrEF, EF <40%) regardless of diabetes status [3]. Dapagliflozin 10 mg once daily reduced the composite of worsening heart failure or CV death by 26% (HR 0.74, 95% CI 0.65 to 0.85, P<0.001) compared with placebo [3]. The benefit was consistent in patients without diabetes, confirming a direct cardiac mechanism beyond glycemic control [3].

The FDA approved Farxiga for HFrEF in May 2020, making it the first SGLT2 inhibitor to receive that specific labeling [4].

EMPEROR-Reduced and EMPEROR-Preserved: Jardiance's Dual HF Coverage

Empagliflozin followed in EMPEROR-Reduced (N=3,730, HFrEF), where it cut the composite of CV death or hospitalisation for heart failure by 25% (HR 0.75, 95% CI 0.65 to 0.86, P<0.001) [5]. Then EMPEROR-Preserved (N=5,988) tested empagliflozin in heart failure with preserved ejection fraction (HFpEF, EF >40%) and showed a 21% reduction in the same composite endpoint (HR 0.79, 95% CI 0.69 to 0.90, P<0.001) [6].

The FDA subsequently approved Jardiance for both HFrEF and HFpEF. Farxiga also received an HFpEF indication following DELIVER (N=6,263), which produced an HR of 0.82 (95% CI 0.73 to 0.92, P<0.001) for CV death or worsening heart failure [7]. As of early 2025, both agents carry dual HF phenotype approvals, narrowing this once-meaningful distinction.

Kidney Protection: DAPA-CKD vs EMPA-KIDNEY

Chronic kidney disease is now a major driver of SGLT2 prescribing decisions, and here the two drugs' trial evidence is directly comparable.

DAPA-CKD Results

DAPA-CKD enrolled 4,304 patients with CKD (eGFR 25 to 75 mL/min/1.73m2) and urine albumin-to-creatinine ratio of at least 200 mg/g, regardless of diabetes status [8]. Dapagliflozin 10 mg reduced the composite of sustained 50% eGFR decline, end-stage kidney disease, or death from renal or CV causes by 39% (HR 0.61, 95% CI 0.51 to 0.72, P<0.001) [8]. The FDA approved Farxiga for CKD in April 2021 [4].

EMPA-KIDNEY Results

EMPA-KIDNEY enrolled 6,609 patients across a broad CKD spectrum (eGFR 20 to 45, or 45 to 90 with elevated ACR) [9]. Empagliflozin 10 mg reduced the primary composite of kidney disease progression or CV death by 28% (HR 0.72, 95% CI 0.64 to 0.82, P<0.001) [9]. The trial was stopped early due to clear efficacy. The FDA approved Jardiance for CKD reduction in 2023 [4].

Interpreting the Numbers

The apparent difference in hazard ratios (0.61 for DAPA-CKD vs 0.72 for EMPA-KIDNEY) does not necessarily mean dapagliflozin is more kidney-protective. The trials enrolled different CKD stages, used different composite endpoints, and ran over different durations. Direct cross-trial comparisons should be made cautiously. Both agents currently appear in ADA Standards of Care as preferred agents in patients with CKD and type 2 diabetes [10].

Real-World Evidence: What Happens Outside Clinical Trials?

Randomised trial populations are selected and monitored. Real-world data capture what happens to typical patients with messy comorbidities, polypharmacy, and variable adherence.

CVD-REAL and the Class Effect Debate

CVD-REAL was an international observational study across six countries that compared SGLT2 inhibitors as a class against other glucose-lowering drugs in roughly 300,000 patients [11]. The study found a 39% lower rate of hospitalisation for heart failure (HR 0.61, 95% CI 0.51 to 0.73, P<0.001) with SGLT2 inhibitors overall [11]. Empagliflozin accounted for 53% of the SGLT2 prescriptions in CVD-REAL, meaning its real-world performance anchored much of the class-level result [11].

OBSERVE-4D and Drug-Specific Real-World Outcomes

OBSERVE-4D used U.S. Insurance claims data to compare canagliflozin, empagliflozin, and dapagliflozin against DPP-4 inhibitors in over 150,000 patients [12]. For hospitalisation for heart failure, all three SGLT2 agents showed similar reductions versus DPP-4 inhibitors (HRs ranging from 0.49 to 0.61) without statistically significant differences between the individual SGLT2 drugs [12]. This finding supports a class effect for the heart failure hospitalisation outcome in real-world practice.

Real-World HbA1c and Weight Data

A 2020 retrospective analysis published in Diabetes Care examined new-user cohorts of empagliflozin and dapagliflozin in U.S. Electronic health records [13]. Both agents produced mean HbA1c reductions of approximately 0.7 percentage points at 6 months (empagliflozin: -0.71%; dapagliflozin: -0.68%; difference not statistically significant) [13]. Body weight reductions were similarly comparable: roughly 2.0 to 2.5 kg at 6 months for both [13].

The table below summarises the key trial and real-world comparisons side by side.

| Domain | Jardiance (Empagliflozin) | Farxiga (Dapagliflozin) | |---|---|---| | MACE reduction (CVOT) | 14% relative reduction, EMPA-REG (N=7,020) [1] | Non-inferior, DECLARE (N=17,160) [2] | | CV death reduction | 38% relative reduction [1] | Not significantly reduced [2] | | HF hospitalisation reduction | 35% relative reduction [1] | 17% composite CV death or HHF [2] | | HFrEF indication | Yes (EMPEROR-Reduced) [5] | Yes (DAPA-HF) [3] | | HFpEF indication | Yes (EMPEROR-Preserved) [6] | Yes (DELIVER) [7] | | CKD indication | Yes (EMPA-KIDNEY) [9] | Yes (DAPA-CKD) [8] | | Real-world HbA1c drop | approx. 0.71% [13] | approx. 0.68% [13] | | Real-world weight reduction | approx. 2.0 to 2.5 kg [13] | approx. 2.0 to 2.5 kg [13] |

Glycemic Efficacy and Blood Sugar Control

For patients whose primary goal is HbA1c reduction, the choice between these two drugs may not matter much from an efficacy standpoint.

Standard Dose Comparisons

Empagliflozin is available as 10 mg and 25 mg. Dapagliflozin is available as 5 mg and 10 mg. Both are taken orally once daily. The FDA-approved prescribing information for each drug reports HbA1c placebo-subtracted reductions of 0.5 to 0.8 percentage points across their Phase 3 programmes. Neither drug requires dose titration in patients with eGFR above 45 mL/min/1.73m2, though prescribing information recommends checking eGFR before initiating either agent [4].

Fasting Glucose and Postprandial Effects

SGLT2 inhibitors work by blocking renal glucose reabsorption regardless of insulin levels, which makes them effective across the insulin resistance and insulin deficiency spectrum [10]. Both empagliflozin and dapagliflozin reduce fasting plasma glucose by approximately 20 to 30 mg/dL at therapeutic doses. Postprandial glucose reductions are modest by comparison, since SGLT2 inhibition is concentration-driven and less effective when renal glucose load is already reduced.

Combination Therapy Considerations

Both agents are approved as monotherapy and as add-ons to metformin, sulfonylureas, insulin, DPP-4 inhibitors, and GLP-1 receptor agonists [4]. Adding either SGLT2 inhibitor to a GLP-1 agonist such as semaglutide or liraglutide produces additive HbA1c reductions of roughly 0.4 to 0.6 additional percentage points versus GLP-1 monotherapy [10]. The 2024 ADA Standards of Care recommend SGLT2 inhibitors with proven cardiorenal benefit as preferred second agents after metformin in patients with established CVD, CKD, or heart failure, regardless of HbA1c target [10].

Safety Profile: Similarities and Key Differences

The shared class mechanism creates a similar safety footprint, but some differences in trial-reported adverse event rates deserve attention.

Genital Mycotic Infections and UTIs

Both drugs increase genital mycotic infections by approximately three- to five-fold compared with placebo, consistent across their Phase 3 programmes [4]. Urinary tract infections are slightly elevated but not consistently across all trials. The prescribing information for both agents warns of the risk and recommends genital hygiene counselling at initiation.

Diabetic Ketoacidosis Risk

Euglycaemic diabetic ketoacidosis (DKA) is a rare but serious risk with all SGLT2 inhibitors. The FDA added a class-wide warning in 2015 [4]. Incidence in trials was below 0.1% for both empagliflozin and dapagliflozin in type 2 diabetes populations. The risk is substantially higher in type 1 diabetes, for which neither drug is FDA-approved.

Amputation and Bone Fracture Signals

Canagliflozin, the third major SGLT2 inhibitor, carries an FDA black box warning for amputation risk based on CANVAS trial data. Neither empagliflozin nor dapagliflozin showed a significant amputation signal in their respective outcome trials [1, 2, 3]. Bone fracture risk was elevated with canagliflozin but not consistently replicated with empagliflozin or dapagliflozin in their CVOTs [1, 2].

Volume Depletion and Blood Pressure

Both drugs produce modest systolic blood pressure reductions of 3 to 5 mmHg, partly through osmotic diuresis [10]. This is generally beneficial in hypertensive patients but requires caution in patients already on loop diuretics or with borderline hypotension. Volume depletion events occurred in roughly 1 to 2% of patients in the Phase 3 programmes for both agents.

Switching From Jardiance to Farxiga (or Vice Versa)

Patients sometimes switch between these agents due to cost, insurance formulary changes, tolerability, or clinical reassessment.

Is a Direct Switch Safe?

Yes. Both drugs are SGLT2 inhibitors with similar half-lives (empagliflozin: approximately 12 hours; dapagliflozin: approximately 12 hours) and can be switched same-day without a washout period. Discontinuing empagliflozin 10 mg and starting dapagliflozin 10 mg the following morning is the standard approach. There is no pharmacokinetic reason for overlap or a gap.

What to Expect After Switching

Glycemic control typically remains stable after switching within the SGLT2 class. A 2021 real-world study in Diabetes, Obesity and Metabolism found no significant change in HbA1c in patients who switched between SGLT2 inhibitors versus those who stayed on the same agent over 12 months [14]. Patients switching for cost reasons should check their new formulary tier carefully. Both branded agents can exceed $500 per month without insurance coverage, and neither has a generic available in the United States as of mid-2025.

When the Switch Has a Clinical Rationale

The one scenario where a formulary-driven switch may carry some clinical nuance involves a patient on empagliflozin specifically for its proven mortality reduction in established ASCVD. The EMPA-REG CV death benefit (HR 0.62) was specific to empagliflozin in that trial population [1]. DECLARE-TIMI 58 did not replicate a significant CV death reduction with dapagliflozin [2]. Whether this reflects drug-specific pharmacology or trial design differences remains unresolved. Clinicians switching a high-risk ASCVD patient from empagliflozin to dapagliflozin for formulary reasons should document the rationale and confirm the new plan with the prescribing cardiologist or endocrinologist.

Current Guideline Positions

ADA Standards of Care 2024

The 2024 ADA Standards of Care state: "For patients with type 2 diabetes and established CVD or high cardiovascular risk, SGLT2 inhibitors with proven cardiovascular benefit are recommended to reduce the risk of major adverse cardiovascular events and/or heart failure hospitalisation" [10]. The guidelines do not specify empagliflozin over dapagliflozin for this indication.

For patients with CKD and albuminuria, the ADA recommends an SGLT2 inhibitor with proven kidney benefit when eGFR is adequate for use [10]. Both empagliflozin and dapagliflozin qualify under that recommendation.

ESC Guidelines 2023

The European Society of Cardiology's 2023 guidelines on heart failure recommend both empagliflozin and dapagliflozin as Class I, Level A recommendations for patients with symptomatic HFrEF regardless of diabetes status, based on EMPEROR-Reduced and DAPA-HF respectively [15]. The guidelines state that "both dapagliflozin and empagliflozin are recommended to reduce the risk of HF hospitalisation and CV death" [15].

Cost and Formulary Considerations

Drug cost can override clinical nuance in practice. Both Jardiance and Farxiga list at $550 to $600 per month without insurance as of 2025. Neither has a generic in the United States. Boehringer Ingelheim and Eli Lilly offer a Jardiance savings card that brings copays down to $10 per month for commercially insured patients who qualify. AstraZeneca offers a similar programme for Farxiga. Medicare Part D patients do not qualify for manufacturer copay cards, making formulary tier placement the dominant cost factor for older adults.