Dapagliflozin Reduces Adverse Renal and Cardiovascular Events in Patients With Chronic Kidney Disease

Conclusion. In patients with CKD, with or without type 2 diabetes, the risk of a composite of a sustained decline in the estimated GFR of at least 50%, end-stage kidney disease, or death from renal or cardiovascular causes was significantly lowered by dapagliflozin treatment.

Commentary

Although SGLT2 inhibitors were designed to reduce plasma glucose and hemoglobin A1c (HbA1c) by increasing urinary glucose excretion in a non-insulin-dependent fashion, an increasing number of clinical trials have demonstrated their possible cardiovascular and renal benefits that extend beyond glycemic control. In 2008, the US Food and Drug Administration (FDA) issued a guidance recommending the evaluation of long-term cardiovascular outcomes prior to approval and commercialization of new antidiabetic therapies to ensure minimum cardiovascular risks following the discovery of cardiovascular safety issues associated with antidiabetic compounds, including rosiglitazone, after drug approval. No one foresaw that this recommendation would lead to the discovery of new classes of antidiabetic drugs (glucagon-like peptide 1 [GLP1] and SGLT2 inhibitors) that improve cardiovascular outcomes. A series of clinical trials of SGLT2 inhibitors, including empagliflozin,¹ canagliflozin,² and dapagliflozin,³ showed a reduction in cardiovascular death and hospitalization due to heart failure among patients with type 2 diabetes. Furthermore, a meta-analysis from 2019 found that SGLT2 inhibitors reduced the risk of a composite of cardiovascular death or hospitalization for heart failure by 23% and the risk of progression of kidney failure by 45% in patients with diabetes.⁴ Thus, the strong and consistent evidence from these large and well-designed outcome trials led the American Diabetes Association in its most recent guidelines to recommend adding SGLT2 inhibitors to metformin for the treatment of patients with type 2 diabetes with or at high risk of atherosclerotic cardiovascular disease, heart failure, or CKD, regardless of baseline HbA1c levels or HbA1c target.⁵ As a result of the compelling effects of SGLT2 inhibitors on cardiovascular outcomes in diabetic patients, as well as increasing evidence that these clinical effects were independent of glycemic control, several subsequent trials were conducted to evaluate whether this new class of drugs may improve clinical outcomes in nondiabetic patients.

The Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure (DAPA-HF) was the first clinical trial to investigate the effect of SGLT2 inhibitors on cardiovascular disease in nondiabetic patients. Findings from DAPA-HF showed that dapagliflozin reduced the risk of worsening heart failure or death from cardiovascular causes, independent of the presence of underlying diabetes. This initial finding resonates with a growing body of evidence^6,7 that supports the use of SGLT2 inhibitors as an adjunctive therapy for heart failure in the absence of diabetes.

The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial showed that long-term administration of canagliflozin conferred cardiovascular, as well as renal, protection in patients with type 2 diabetes with CKD.⁸ Similar to the protective effects on heart failure, the renal benefits of SGLT2 inhibitors appeared to be independent of their blood glucose-lowering effects. Thus, these recent discoveries led to the design of the DAPA-CKD trial to further assess the long-term efficacy and safety of the SGLT2 inhibitor dapagliflozin in patients with CKD precipitated by causes other than type 2 diabetes. Although diabetes is the most common cause for CKD, it nonetheless only accounts for 40% of all CKD etiologies. To date, the only classes of medication that have been shown to slow a decline in kidney function in patients with diabetes are angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). Given that CKD is an important contributor to illness, is associated with diminished quality of life and reduced life expectancy, and increases health care costs, the findings of the DAPA-CKD trial are particularly significant as they show a renal benefit of dapagliflozin treatment across CKD stages that is independent of underlying diabetes. Therefore, SGLT2 inhibitors may offer a new and unique treatment option for millions of patients with CKD worldwide for whom ACE inhibitors and ARBs were otherwise the only treatments to prevent kidney failure. Moreover, with a number-needed-to-treat of 19 to prevent 1 composite renal vascular event over a period of 2.4 years, dapagliflozin requires a much lower number needed to treat compared to ACE inhibitors and ARBs in similar patients.

The trial has several limitations in study design. For example, the management of diabetes and hypertension were left to the discretion of each trial site, in keeping with local clinical practice and guidelines. It is unknown whether this variability in the management of comorbidities that impact kidney function had an effect on the study’s results. In addition, the trial was stopped early as a result of recommendations from an independent committee due to the demonstrated efficacy of dapagliflozin. This may have reduced the statistical power to assess some of the secondary outcomes. Finally, the authors discussed an initial dip in the estimated GFR after initiation of dapagliflozin treatment, similar to that observed in other SGLT2 inhibitor clinical trials. However, they were unable to ascertain the reversibility of this effect after the discontinuation of dapagliflozin because assessment of GFR was not completed after trial closure. Nonetheless, the authors specified that the reversibility of this initial estimated GFR dip had been assessed and observed in other clinical trials involving dapagliflozin.

The nonglycemic benefits of SGLT2 inhibitors, including improvement in renal outcomes, have strong implications for the future management of patients with CKD. If this indication is approved by the FDA and recommended by clinical guidelines, the ease of SGLT2 inhibitor prescription (eg, minimal drug-drug interaction, no titration), treatment administration (orally once daily), and safety profile may lead to wide use of SGLT2 inhibitors by generalists, nephrologists, and endocrinologists in preserving or improving renal outcomes in patients at risk for end-stage kidney disease. Given that SGLT2 inhibitors are a new class of pharmacologic therapeutics, patient education should include a discussion of the possible side effects, such as euglycemic ketoacidosis, genital and urinary tract infection, and foot and leg amputation. Finally, as Strandberg and colleagues reported in a recent commentary,⁹ the safety of SGLT2 inhibitors in older adults with multimorbidity, frailty, and polypharmacy remains unclear. Thus, future studies of SGLT2 inhibitors are needed to better evaluate their clinical effects in older adults.

Applications for Clinical Practice

This trial enrolled a dedicated patient population with CKD and demonstrated a benefit of dapagliflozin in reducing renal and cardiovascular outcomes, regardless of baseline diabetes status. These drugs (dapagliflozin as well as other SGLT2 inhibitors) will likely have a prominent role in future CKD management guidelines. Until then, several barriers remain before SGLT2 inhibitors can be widely used in clinical practice. Among these barriers are FDA approval for their use in patients with and without diabetes with an estimated GFR < 30 mL/min/1.73 m² and lowering the costs of this class of drugs.

—Rachel Litke, MD, PhD
Icahn School of Medicine at Mount Sinai
Fred Ko, MD, MS