How do SGLT2 inhibitors protect the kidney? A mediation analysis of the EMPA-REG OUTCOME trial

INTRODUCTION

Mechanisms underlying kidney benefits with sodium-glucose cotransporter-2 (SGLT2) inhibition in heart failure and/or type 2 diabetes (T2D) with established cardiovascular disease are currently unclear.

METHODS

We evaluated post hoc the factors mediating the effect of empagliflozin on a composite kidney outcome (first sustained estimate glomerular filtration rate ≥40% reduction from baseline, initiation of renal replacement therapy, or death due to kidney disease) in EMPA-REG OUTCOME. Variables, calculated as change from baseline or updated mean, were evaluated as time-dependent covariates and using a landmark approach (at Week 12) in Cox regression analyses. In multivariable analyses, variables with the greatest mediating effect were added using a step-up procedure.

RESULTS

In univariable time-dependent updated mean covariate analyses, the strongest mediator was hematocrit (99.5% mediation). Hemoglobin, uric acid, and urine albumin-to-creatinine ratio mediated 79.4%, 33.2%, and 31.0%, respectively. Multivariable analyses were not performed due to the very strong mediation effect of hematocrit. In univariable Week 12 landmark change from baseline analyses, the strongest mediators included hematocrit (40.7%), glycated hemoglobin (28.3%), systolic blood pressure (16.8%), and free fatty acids (16.5%), which yielded a combined mediation of 78.9% in multivariable analysis.

CONCLUSIONS

Changes in hematocrit and hemoglobin were the strongest mediators of empagliflozin's kidney benefits in EMPA-REG OUTCOME participants with T2D and cardiovascular disease.

Dapagliflozin as an Adjunct Therapy to Insulin in Patients with Type 1 Diabetes Mellitus: Efficacy and Safety of this Combination

The prevalence of type 1 diabetes (T1D) is increasing worldwide. T1D reduces life expectancy due to complications including cardiovascular disease. Sodium-glucose co-transporter (SGLT) inhibitors are a new class of drugs developed to treat type 2 diabetes (T2D), and now they can be used as an adjunct to insulin in T1D. In clinical trials, they have been shown to improve glycaemic control and decrease body weight without the risk of increased hypoglycaemia and with a reduction in insulin dose. Four SGLT2 inhibitors have been approved in Europe for the treatment of T2D, while only dapagliflozin and sotagliflozin, a dual SGLT1 and SGLT2 inhibitor approved in 2019, have been approved for the treatment of T1D. Both can be used as an adjunct therapy in combination with insulin in adults with a body mass index (BMI) of ≥27 kg/m², inadequately controlled with insulin. In Europe, dapagliflozin is the only currently available SGLT2 inhibitor indcated as adjunct therapy for patients with T1D. The subgroup of patients with a BMI of ≥27 kg/m² from the DEPICT-1 and -2 trials (Dapagliflozin Evaluation in Patients with Inadequately Controlled Type 1 diabetes) showed similar reduction in hyperglycaemia and body weight but no significant increased risk of diabetic ketoacidosis (DKA) than the overall trial population. The risk of DKA has been shown to increase in patients with T1D treated with adjunct therapy with SGLT2 inhibitors, and studies on sotagliflozin and empagliflozin have suggested a dose response. Thus, it is important to educate patients and doctors how to recognize symptoms of upcoming DKA and mitigate it. An independent DKA education programme has recently been developed to instruct patients with T1D being treated with SGLT inhibitor therapies with and without insulin pumps to prevent, identify and treat DKA. Despite these considerations, clinical trials support the use of SGLT2 inhibitors in the management of T1D. The benefits and potential risks of dapagliflozin as an adjunct therapy to insulin in adults with T1D should be considered in each individual case. Here we discuss the efficacy and safety of dapagliflozin as adjunct therapy in patients with T1D.

Efficacy and safety of titrated canagliflozin in patients with type 2 diabetes mellitus inadequately controlled on metformin and sitagliptin

AIMS

To evaluate the efficacy and safety of titrated canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus (T2DM) inadequately controlled on metformin and sitagliptin.

METHODS

In this randomized, double-blind study, patients with T2DM (N = 218) on metformin ≥1500 mg/day and sitagliptin 100 mg received canagliflozin 100 mg or placebo. After 6 weeks, the canagliflozin dose was increased from 100 to 300 mg (or from placebo to matching placebo) if all of the following criteria were met: baseline estimated glomerular filtration rate ≥70 ml/min/1.73 m(2) ; fasting self-monitored blood glucose ≥5.6 mmol/l (≥100 mg/dl); and no volume depletion-related adverse events (AEs) within 2 weeks before dose increase. Endpoints included change in glycated haemoglobin (HbA1c) at week 26 (primary); proportion of patients achieving HbA1c <7.0%; and changes in fasting plasma glucose (FPG), body weight and systolic blood pressure (SBP). Safety was assessed using AE reports.

RESULTS

Overall, 85.4% of patients were titrated to canagliflozin 300 mg or matching placebo (mean ± standard deviation time to titration 6.2 ± 0.8 weeks). At week 26, canagliflozin (pooled 100 and 300 mg) demonstrated superiority in HbA1c reduction versus placebo (-0.91% vs. -0.01%; p < 0.001). Canagliflozin provided significant reductions in FPG, body weight and SBP compared with placebo (p < 0.001). The overall AE incidence was 39.8 and 44.4% for canagliflozin and placebo, respectively. Canagliflozin was associated with an increased incidence of genital mycotic infections.

CONCLUSIONS

Titrated canagliflozin significantly improved HbA1c, FPG, body weight and SBP, and was generally well tolerated over 26 weeks in patients with T2DM as add-on to metformin and sitagliptin.