SGLT2 Inhibitors for Cardiovascular and Renal Protection

Definition and pharmacological basis

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a class of oral agents initially developed for glucose lowering in type 2 diabetes mellitus (T2DM). The principal drugs identified in the source material are canagliflozin, dapagliflozin and empagliflozin; sotagliflozin is a related dual SGLT1/SGLT2 inhibitor.

SGLT2 is a high-capacity, low-affinity transporter situated in the S1 and S2 segments of the renal proximal tubule. It accounts for approximately 90% of renal glucose reabsorption. The remaining glucose is reabsorbed by SGLT1 in the S3 segment. SGLT2 also mediates proximal tubular sodium reabsorption, with chloride following passively down the resulting electrochemical gradient.

By inhibiting SGLT2, these drugs produce coupled sodium and glucose loss in approximately a 1:1 stoichiometric relationship. The resulting glucosuria and natriuresis reduce proximal tubular workload, contract plasma volume and modestly lower blood pressure. Increased sodium delivery to the macula densa restores tubuloglomerular feedback, causing afferent arteriolar vasoconstriction and reducing glomerular hyperfiltration.

The cardiovascular and renal effects extend beyond glycaemic control. Proposed mechanisms include:

• Reduction in glomerular hypertension and hyperfiltration

• Decreased tubular energy demand and oxygen consumption

• Natriuresis and diuresis

• Reduction in plasma volume, preload and afterload

• Lower left ventricular wall stress

• Reduced sympathetic nervous system activity

• Improvement in cardiac metabolic efficiency, including increased oxygen delivery and beta-hydroxybutyrate oxidation

• Reduced sodium-hydrogen exchanger subtype 3 activity

• Attenuation of oxidative stress, inflammation and fibrosis

• Reduction in body weight and haemoglobin A1c

• Increased uricosuria, with plasma uric acid reduction of approximately 10% to 15%

• Possible effects on erythropoietin activity and erythropoiesis

SGLT2 inhibition may also activate adenosine 5′-monophosphate-activated protein kinase and inhibit mammalian target of rapamycin complex 1 signalling, thereby reducing inflammatory mediator expression and glycolytic activity in relevant renal and cardiovascular cells. These cellular mechanisms remain proposed explanations for observed clinical effects.

Cardiovascular and renal disease associations

Diabetes substantially increases the risk of atherosclerotic cardiovascular disease, myocardial infarction, stroke, heart failure, atrial fibrillation and peripheral artery disease. Prognosis is generally worse when diabetes coexists with these conditions. However, the cardiovascular effects of SGLT2 inhibitors are not explained simply by their effects on haemoglobin A1c.

Clinical benefits have been demonstrated in several overlapping populations:

• T2DM with established cardiovascular disease or high cardiovascular risk

• T2DM with chronic kidney disease

• Heart failure with reduced ejection fraction (HFrEF), with or without diabetes

• Heart failure across the ejection-fraction spectrum, according to the guideline key points

• Patients with renal insufficiency and cardiovascular disease, irrespective of diabetes status

The clearest and most consistent cardiovascular signal is reduction in hospitalization for heart failure. Benefits also include reductions in cardiovascular death, major adverse cardiovascular events and adverse renal outcomes in selected populations.

Clinical presentation and symptoms

SGLT2 inhibitors are preventive and disease-modifying therapies rather than treatments directed at a particular symptom complex. The source material does not describe a characteristic symptom profile at initiation or during routine therapy.

Potential clinically important complications and treatment-related syndromes include:

• Hypovolaemia

• Falls and syncope, particularly in older adults

• Euglycaemic diabetic ketoacidosis (EDKA), a rare but potentially life-threatening complication

• A reversible early decline in estimated glomerular filtration rate (eGFR)

EDKA may occur despite the absence of marked hyperglycaemia. Reported precipitating circumstances include changes in diabetes medication, dietary modification, intercurrent illness and non-cardiac surgery. Symptoms suggestive of ketoacidosis should prompt ketone assessment, although the source material does not provide a detailed symptom list.

Evaluation and physical examination

Assessment before and during treatment should focus on the patient’s cardiovascular, renal and volume status. The source material supports particular attention to:

• Heart failure severity and clinical stability

• Blood pressure, including the possibility of modest treatment-related reduction

• Volume status, especially when the patient is receiving diuretics

• Symptoms or signs of hypovolaemia

• Risk of falls or syncope in older adults

• Renal function and its early post-treatment trajectory

• Intercurrent illness, dietary change or planned surgery

• Risk factors for ketoacidosis, including insulin deficiency

The source does not provide a standardized physical-examination protocol, specific examination findings, or diagnostic thresholds for initiating or withholding therapy.

Diagnostic assessment

Electrocardiography and electrophysiology

Routine ECG criteria, electrophysiological indications and specific rhythm-monitoring protocols are not provided in the source material.

SGLT2 inhibitors have been associated in retrospective and meta-analytic data with a possible reduction in atrial fibrillation incidence. However, prospective trials addressing atrial fibrillation prevention in patients with obesity, T2DM and heart failure are described as ongoing. The available evidence therefore does not establish an electrophysiological indication for SGLT2 inhibition or support prescribing these drugs solely to prevent atrial fibrillation.

Cardiac imaging

The relevant heart failure trials enrolled patients with symptomatic HFrEF and left ventricular ejection fraction (LVEF) ≤40%. The source material does not provide imaging criteria for other heart failure phenotypes, nor does it describe specific echocardiographic changes attributable to treatment.

Renal assessment

Renal evaluation is central to treatment decisions. Relevant measures include:

• eGFR

• Albuminuria, assessed by urinary albumin-to-creatinine ratio

• Serum creatinine

• Serum potassium, particularly when treatment is combined with renin-angiotensin-aldosterone system inhibitors or mineralocorticoid receptor antagonists

The early eGFR decline after initiation is generally reversible and reflects reduced glomerular hypertension rather than acute kidney injury. A typical decline of approximately 3–5 mL/min/1.73 m2 is described, with recovery toward baseline over subsequent weeks to months.

Biomarkers and laboratory findings

Glycaemic measures

SGLT2 inhibitors lower plasma glucose and haemoglobin A1c, although the source emphasizes that cardiovascular and heart failure benefits appear largely independent of the magnitude of haemoglobin A1c reduction.

Renal markers

An initial eGFR reduction of approximately 3–5 mL/min/1.73 m2 may occur after treatment initiation. This change is usually reversible and, in isolation, does not require discontinuation. Over the longer term, SGLT2 inhibitors slow decline in renal function.

In patients with T2DM and chronic kidney disease, SGLT2 inhibitors reduce the risk of adverse kidney outcomes. They can be used in patients with any level of albuminuria when eGFR is above 20 mL/min/1.73 m2, according to the cited diabetes and kidney disease guidance.

Volume-related laboratory changes

Plasma-volume contraction may produce haemoconcentration, including:

• Increased blood urea nitrogen

• Increased haematocrit

The haematocrit rise may also reflect increased erythropoiesis.

Uric acid

Increased urinary uric acid excretion reduces plasma uric acid by approximately 10% to 15%. Elevated uric acid has been implicated in heart failure through oxidative stress and inflammation, although the source does not establish uric acid reduction as an independent treatment target.

Ketones and ketoacidosis

When EDKA is suspected, ketones should be measured. Because EDKA may occur without substantial hyperglycaemia, glucose concentration alone is insufficient to exclude this complication.

Potassium

SGLT2 inhibitors may reduce serious hyperkalaemia, defined in the source as serum potassium ≥6 mmol/L, across eGFR categories. This effect may facilitate continuation or titration of other guideline-directed therapies, including angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and mineralocorticoid receptor antagonists. Nevertheless, serum potassium requires monitoring when these therapies are combined.

Evidence for cardiovascular protection

Type 2 diabetes with established cardiovascular disease

In EMPA-REG OUTCOME, 7020 patients with T2DM, established cardiovascular disease and eGFR above 30 mL/min/1.73 m2 were randomized to empagliflozin or placebo. Empagliflozin reduced:

• Major adverse cardiovascular events by 14%: hazard ratio 0.86, 95% confidence interval 0.74–0.99

• Cardiovascular death by 38%: hazard ratio 0.62, 95% confidence interval 0.49–0.77

• Hospitalization for heart failure by 35%: hazard ratio 0.65, 95% confidence interval 0.50–0.85

The same study is also described as demonstrating reduced progression to end-stage kidney disease.

Heart failure with reduced ejection fraction

The heart failure benefits of SGLT2 inhibition occur in patients with and without diabetes.

In DAPA-HF, 4744 patients with symptomatic NYHA class II–IV heart failure and LVEF ≤40% received dapagliflozin 10 mg once daily or placebo in addition to guideline-directed medical therapy. After a median follow-up of 18.2 months, dapagliflozin reduced the composite of worsening heart failure or cardiovascular death by 26%:

• Hazard ratio 0.74

• 95% confidence interval 0.59–0.83

• P = .00001

Hospitalization for worsening heart failure was reduced, with a hazard ratio of 0.70. Cardiovascular death was also reduced, with a hazard ratio of 0.82. The findings were similar in participants with and without diabetes.

In EMPEROR-Reduced, 3730 patients with NYHA class II–IV heart failure and LVEF ≤40% received empagliflozin 10 mg once daily or placebo alongside standard therapy. After a median follow-up of 16 months, empagliflozin reduced the composite of cardiovascular death or hospitalization for worsening heart failure by 25%:

• Hazard ratio 0.75

• 95% confidence interval 0.65–0.86

• P < .001

The treatment effect was again consistent regardless of diabetes status. The primary outcome was driven principally by fewer heart failure hospitalizations, with a hazard ratio of 0.70. Cardiovascular mortality did not differ significantly in this trial, with a hazard ratio of 0.92 and a 95% confidence interval of 0.75–1.12.

A meta-analysis of DAPA-HF and EMPEROR-Reduced found reductions in:

• All-cause mortality by 13%: pooled hazard ratio 0.87, 95% confidence interval 0.77–0.98

• Cardiovascular mortality by 14%: pooled hazard ratio 0.86, 95% confidence interval 0.76–0.98

• Renal endpoints: pooled hazard ratio 0.62, 95% confidence interval 0.43–0.90

The treatment effect was consistent across age groups. However, SGLT2 inhibitors may be less effective in advanced heart failure, although the source presents this as a possible explanation for differences between the major trials rather than as a definitive conclusion.

Dual SGLT1/SGLT2 inhibition

In SOLOIST-WHF, sotagliflozin reduced the combined outcome of cardiovascular death, heart failure hospitalization or urgent heart failure hospitalization by 33%:

• Hazard ratio 0.67

• 95% confidence interval 0.52–0.85

• P < .001

The source states that sotagliflozin was not FDA-approved for treatment of heart failure at the time described.

Effects on blood pressure and volume

SGLT2 inhibitors lower blood pressure modestly without increasing heart rate. A meta-analysis of seven randomized trials found an average reduction in 24-hour ambulatory blood pressure of:

The blood-pressure effect was greater than that observed with GLP-1 receptor agonists and was comparable to low-dose hydrochlorothiazide in the cited analysis.

Through natriuresis, osmotic diuresis and plasma-volume contraction, SGLT2 inhibitors may augment the effect of conventional diuretics. This can be beneficial in congestion but may increase the risk of hypovolaemia, falls and syncope. Particular caution is therefore required in older adults and in patients receiving loop or other diuretic therapy.

Treatment and management

Position within guideline-directed therapy

In HFrEF, SGLT2 inhibitors are considered foundational therapy alongside:

• Angiotensin receptor-neprilysin inhibition or other renin-angiotensin system therapy

• Beta-blockade

• Mineralocorticoid receptor antagonism

The source describes consensus guideline support for their use as part of guideline-directed medical therapy, independent of diabetes status.

For patients with chronic kidney disease and concomitant atherosclerotic cardiovascular disease or heart failure, SGLT2 inhibitors are recommended in addition to moderate- to high-intensity statin therapy for atherosclerotic disease. In T2DM and chronic kidney disease, they are generally added to an ACE inhibitor or ARB when renal function permits.

Initiation and dosing

The specific doses stated in the source are:

The source does not provide dosing details for canagliflozin, ertugliflozin or sotagliflozin outside the trial information described.

Renal considerations

For T2DM with chronic kidney disease, the source recommends adding an SGLT2 inhibitor when eGFR is >20 mL/min/1.73 m2, with any level of albuminuria, while continuing ACE inhibitor or ARB therapy when indicated.

An early eGFR dip of approximately 3–5 mL/min/1.73 m2 is expected and is generally reversible. This should not automatically be interpreted as acute kidney injury or prompt drug withdrawal. Continued assessment is required if renal function falls substantially, if volume depletion is present or if other clinical features suggest acute kidney injury.

ACE inhibitors or ARBs may be continued in HFrEF even when eGFR is below 30 mL/min/1.73 m2, provided hyperkalaemia is monitored closely. SGLT2 inhibitors, sacubitril/valsartan and potassium binders may help mitigate hyperkalaemia and permit continuation or titration of guideline-directed therapy.

Interaction with diuretics

Because SGLT2 inhibitors can enhance diuresis and lower blood pressure, the diuretic regimen should be reviewed at initiation. In older adults or patients at risk of hypovolaemia, consideration should be given to reducing the diuretic dose. Ongoing reassessment should include blood pressure, symptoms, orthostatic tolerance where clinically relevant and renal indices.

Perioperative management

SGLT2 inhibitors should be withheld before elective surgery because of the risk of EDKA. The source cites interruption for at least 3–4 days before scheduled surgery, while another passage advises holding therapy for several days. Patients should be monitored for symptoms suggestive of EDKA, and ketones should be measured when clinically indicated.

Diabetes and kidney disease

For T2DM with chronic kidney disease:

• Continue or initiate ACE inhibitor or ARB therapy when albuminuria is present and monitor creatinine and potassium.

• Add an SGLT2 inhibitor when eGFR is above 20 mL/min/1.73 m2.

• If glycaemic targets are not achieved, or if SGLT2 inhibitors and metformin cannot be used, add a long-acting GLP-1 receptor agonist.

• Consider finerenone for persistent albuminuria after ACE inhibitor or ARB plus SGLT2 inhibitor therapy when eGFR is ≥25 mL/min/1.73 m2 and serum potassium is <4.8 mmol/L.

In patients with type 1 diabetes or insulin-deficient T2DM, SGLT2 inhibitors require caution because of the increased risk of EDKA. Patient education should include ketone monitoring and recognition of diabetic ketoacidosis.

Guideline recommendations

The recommendations provided in the source are summarized below.

The source also states that SGLT2 inhibitors improve heart failure outcomes across the spectrum of ejection fraction and can reduce cardiovascular and kidney failure risk in T2DM with chronic kidney disease.

Safety and practical precautions

Euglycaemic diabetic ketoacidosis

EDKA is rare but serious. It may be precipitated by:

• Surgery

• Intercurrent illness

• Dietary modification

• Changes in diabetes medication

• Insulin deficiency

The absence of marked hyperglycaemia does not exclude the diagnosis. Therapy should be interrupted before scheduled surgery, and ketones should be checked when symptoms or clinical circumstances raise concern.

Hypovolaemia and hypotension

Natriuresis and osmotic diuresis may cause excessive volume depletion, particularly when SGLT2 inhibitors are combined with diuretics. Older adults may be especially vulnerable to hypovolaemia, falls and syncope. Dose reduction of concomitant diuretics may be appropriate.

Renal function

The expected early eGFR decline is usually reversible and reflects correction of glomerular hyperfiltration. It is not, by itself, an indication to discontinue treatment. More pronounced or progressive renal deterioration requires clinical reassessment.

Hyperkalaemia and concomitant therapy

SGLT2 inhibitors may reduce serious hyperkalaemia and can facilitate the use of ACE inhibitors, ARBs and mineralocorticoid receptor antagonists. Serum potassium and renal function should nevertheless be monitored, particularly in advanced chronic kidney disease and when multiple potassium-increasing therapies are prescribed.

Prognosis and follow-up

SGLT2 inhibitors improve cardiovascular and renal prognosis in the populations studied. Benefits include fewer heart failure hospitalizations, reduced cardiovascular death in selected trials, lower major adverse cardiovascular event rates in high-risk T2DM, and slower progression of renal disease.

Follow-up should assess:

• Symptoms and signs of congestion or volume depletion

• Blood pressure and tolerance of combined diuretic therapy

• Serum creatinine and eGFR after initiation

• Serum potassium when used with renin-angiotensin-aldosterone system inhibitors or mineralocorticoid receptor antagonists

• Glycaemic control in patients with diabetes

• Albuminuria in chronic kidney disease

• Intercurrent illness and perioperative status

• Symptoms suggestive of ketoacidosis and the need for ketone testing

In diabetic kidney disease, urinary albumin-to-creatinine ratio may be reassessed one to four times annually as part of renal risk management. Nephrology consultation is indicated in the source when eGFR is below 30 mL/min/1.73 m2, albuminuria exceeds 300 mg/g creatinine, or atypical features such as haematuria or rapidly declining renal function are present.

The long-term treatment objective is sustained cardiorenal protection while preserving the broader guideline-directed regimen. The initial eGFR dip should generally be interpreted within this therapeutic framework rather than as treatment failure, provided the patient remains clinically stable and does not develop evidence of acute kidney injury or significant volume depletion.