Sodium glucose cotransporter 2 inhibition to improve outcomes in type 2 diabetes and chronic kidney disease

Type 2 diabetes is a major global health issue. It is projected that by 2045, 783 million people worldwide will be living with diabetes, making it one of the leading contributors to premature death globally. Approximately 30 to 40% of individuals with diabetes develop chronic kidney disease (CKD), making diabetes the leading cause of CKD worldwide. Despite glucose, blood pressure and lipid lowering, and treatment with renin-angiotensin system (RAS) blockade, the risk of cardiovascular events, kidney failure and death remains high for millions of people with diabetes and CKD worldwide. Originally developed to lower blood glucose, sodium-glucose cotransporter 2 (SGLT2) inhibitors have been shown to have favourable effects on multiple metabolic risk factors including blood pressure, glucose, body weight and albuminuria. Large, randomized trials, including those reported herein, have demonstrated the capacity of these agents to reduce the risk of cardiovascular events, kidney failure and extend survival in increasingly diverse populations, including those without diabetes. This doctorate aims to evaluate the efficacy and safety of SGLT2 inhibitors in people with type 2 diabetes and CKD. Chapter 1 introduces the doctorate, summarizing the epidemiology of type 2 diabetes and CKD, as well as traditional approaches to improving outcomes in this population and the potential role for SGLT2 inhibition in people with diabetes. Chapter 2 provides an overview of SGLT2 inhibitors, practical considerations and evidence for their use in people with type 2 diabetes from cardiovascular outcome trials. Chapters 3 to 5 assess the efficacy and safety of the SGLT2 inhibitor, canagliflozin, across different levels of kidney function, defined by estimated glomerular filtration rate (eGFR) and albuminuria, using data from the CANVAS Program. Whilst the relative effects of canagliflozin on cardiovascular and kidney outcomes are consistent across different levels of eGFR and albuminuria, absolute risk reductions are largest for individuals with severely increased albuminuria. Further, the Kidney Disease Improving Global Outcomes classification of CKD, which combines eGFR and albuminuria to risk stratify individuals, can accurately identify those who are likely to derive the greatest absolute benefits with treatment. In Chapter 6, the results of a systematic review and meta-analysis are presented, which demonstrate that for people with type 2 diabetes, SGLT2 inhibitors substantially reduce the risk of the most important patient-centred kidney outcome – the need for dialysis, kidney transplantation or death due to kidney disease – and provide protection against acute kidney injury. The results of a meta-analysis are presented in Chapter 7, indicating that the benefits of SGLT2 inhibitors are similar with and without metformin, which is widely recommended as first-line glucose lowering therapy in type 2 diabetes. In Chapter 8, an individual participant data meta-analysis demonstrated that SGLT2 inhibitors reduce the risk of serious hyperkalaemia in people with type 2 diabetes at high cardiovascular risk and/or with CKD, which may enable better use of RAS blockade and mineralocorticoid receptor antagonists to improve cardiorenal outcomes. Chapter 9 explores questions about this class of agent that remain to be answered by ongoing randomized trials, and how SGLT2 inhibitors and other kidney protective therapies might be used for people with CKD in the future. Taken together, the findings of this doctorate provide compelling evidence that SGLT2 inhibitors should be routinely offered to individual with type 2 diabetes to safely reduce the risk of major kidney outcomes and cardiovascular events

Chronic kidney disease

Chronic kidney disease is a progressive disease with no cure and high morbidity and mortality that occurs commonly in the general adult population, especially in people with diabetes and hypertension. Preservation of kidney function can improve outcomes and can be achieved through non-pharmacological strategies (eg, dietary and lifestyle adjustments) and chronic kidney disease-targeted and kidney disease-specific pharmacological interventions. A plant-dominant, low-protein, and low-salt diet might help to mitigate glomerular hyperfiltration and preserve renal function for longer, possibly while also leading to favourable alterations in acid-base homoeostasis and in the gut microbiome. Pharmacotherapies that alter intrarenal haemodynamics (eg, renin-angiotensin-aldosterone pathway modulators and SGLT2 [SLC5A2] inhibitors) can preserve kidney function by reducing intraglomerular pressure independently of blood pressure and glucose control, whereas other novel agents (eg, non-steroidal mineralocorticoid receptor antagonists) might protect the kidney through anti-inflammatory or antifibrotic mechanisms. Some glomerular and cystic kidney diseases might benefit from disease-specific therapies. Managing chronic kidney disease-associated cardiovascular risk, minimising the risk of infection, and preventing acute kidney injury are crucial interventions for these patients, given the high burden of complications, associated morbidity and mortality, and the role of non-conventional risk factors in chronic kidney disease. When renal replacement therapy becomes inevitable, an incremental transition to dialysis can be considered and has been proposed to possibly preserve residual kidney function longer. There are similarities and distinctions between kidney-preserving care and supportive care. Additional studies of dietary and pharmacological interventions and development of innovative strategies are necessary to ensure optimal kidney-preserving care and to achieve greater longevity and better health-related quality of life for these patients

SGLT2 inhibitors for patients with type 2 diabetes and CKD: a narrative review

Sodium‐glucose co-transporter 2 (SGLT2) inhibitors have recently emerg ed as an effective means to protect kidney function in people with type 2 diabetes and chronic kidney disease (CKD). In this review, we explore the role of SGLT2 inhibition in these individuals. SGLT2 inhibitors specifically act to inhibit sodium and glucose reabsorption in the early proximal tubule of the renal nephron. Although originally developed as glucose-lowering agents through their ability to induce glycosuria, it became apparent in cardiovascular outcome trials that the trajectory of kidney function decline w as significantly slowed and the incidence of serious falls in kidney function was reduced in participants receiving an SGLT2 inhibitor. These observations have recently led to spe cific outcome trials in participants with CKD, including DAPA-CKD, CREDENCE and EMPA-KIDNEY, and real-world studies, like CVD-REAL-3, that have confirmed the observation of kidney benefits in this setting. In response, recent KDIGO Guidelines have recommended the use of SGLT2 inhibitors as first-line therapy in patients with CKD, alongside statins, renin–angiotensin– aldosterone system inhibitors and multifactorial risk factor management as indicated. However, SGLT2 inhibitors remain significantly underutilized in the setting of CKD. Indeed, an inertia paradox exists, with patients with more severe disease less likely to receive an SGLT2 inhibitor. Concerns regarding safety appear unfounded, as acute kidney injury, hyperkalaemia, major acute cardiovascular events and cardiac death in patients with CKD appear to be lower following SGLT2 inhibition. The first-in-clas s indication of dapagliflozin for CKD may begin a new approach to managing kidney disease in type 2 diabetes

Mediators of the effects of canagliflozin on kidney protection in patients with type 2 diabetes

Canagliflozin reduced kidney disease progression in participants with type 2 diabetes in the CANagliflozin cardioVascular Assessment Study (CANVAS) Program that explored potential mediators of the effects of canagliflozin on kidney outcomes. The percent mediating effect of 18 biomarkers indicative of disease was determined by comparing the hazard ratios for the effect of randomized treatment from an unadjusted model and from a model adjusting for the average post-randomization level of each biomarker. Multivariable analyses assessed the joint effects of biomarkers that mediated most strongly in univariable analyses. The kidney outcome was defined as a composite of 40% estimated glomerular filtration rate decline, end-stage kidney disease, or death due to kidney disease. Nine biomarkers (systolic blood pressure [8.9% of effect explained], urinary albumin:creatinine ratio [UACR; 23.9%], gamma glutamyltransferase [4.1%], hematocrit [51.1%], hemoglobin [41.3%], serum albumin [19.5%], erythrocytes [56.7%], serum urate [35.4%], and urine pH [7.5%]) individually mediated the effect of canagliflozin on the kidney outcome. In a parsimonious multivariable model, erythrocyte concentration, serum urate, and systolic blood pressure maximized cumulative mediation (115%). Mediating effects of UACR, but not other mediators, were highly dependent upon the baseline level of UACR: UACR mediated 42% and 7% of the effect in those with baseline UACR 30 mg/g or more and under 30 mg/g, respectively. The identified mediators support existing hypothesized mechanisms for the prevention of kidney outcomes with sodium glucose co-transporter 2 inhibitors. Thus, the disparity in mediating effects across baseline UACR subgroups suggests that the mechanism for kidney protection with canagliflozin may vary across patient subgroups

An exploration of the heterogeneity in effects of SGLT2 inhibition on cardiovascular and all-cause mortality in the EMPA-REG OUTCOME, CANVAS Program, DECLARE-TIMI 58, and CREDENCE trials

Background: Large-scale outcome trials of sodium glucose co-transporter 2 (SGLT2) inhibitors in patients with type 2 diabetes have identified consistent effects on major adverse cardiovascular events, heart failure, and progression of kidney disease. However, the magnitude of effects on cardiovascular and all-cause death appeared to vary between some of the studies. Methods: We explored the impact of differences in trial methodologies, participant characteristics, types of deaths, follow-up duration, effects on intermediate markers of risk, and drug selectivity for SGLT2 on the magnitude of the protective effect against fatal events achieved in the 4 trials. Results: The trial populations differed substantively in the proportions with baseline atherosclerotic cardiovascular disease history (99.2% in EMPA-REG OUTCOME to 40.6% in DECLARE-TIMI 58), and macroalbuminuria (88.0% in CREDENCE to 7.6% in the CANVAS Program). Meta-regression analyses identified no clear effect of these (both P > 0.09) or other participant characteristics on mortality benefits (all P > 0.55). Other differences between the trials (duration, selectivity of the SGLT2 inhibitor, or effects on intermediate markers of risk) also did not explain the heterogeneity in effects on mortality observed (all P > 0.30). Conclusion: No clear explanation for the statistical evidence of heterogeneity in effects of SGLT2 inhibition on fatal outcomes between the trials could be identified. While the analyses had limited statistical power, these results raise the possibility that the observed variations in treatment effects on fatal outcomes between trials may be at least partly due to chance

Kidney protection with canagliflozin: A combined analysis of the randomized CANVAS program and CREDENCE trials

AIM: In the CANVAS Program and CREDENCE trials, the sodium glucose co-transporter 2 inhibitor canagliflozin reduced the risk of cardiovascular and kidney events in patients with type 2 diabetes. The current study analysed a pooled population to ascertain the kidney protection provided by canagliflozin across the full spectrum of kidney parameters. METHODS: This post-hoc pooled analysis of the CANVAS Program (N = 10 142) and CREDENCE trial (N = 4401), assessed the risk of the primary kidney composite (doubling of serum creatinine, end-stage kidney disease, renal death), in all patients and subgroups defined by baseline estimated glomerular filtration rate (300 mg/g (33.9 mg/mmol)] and 2012 Kidney Disease: Improving Global Outcomes (KDIGO) classification of chronic kidney disease (low/moderate, high and very high risk). RESULTS: In the overall population, the risk for the primary kidney composite outcome was 37% lower in the canagliflozin group versus placebo (HR: 0.63; 95% CI: 0.53, 0.77; p  .05). A statistically significant risk reduction of the primary kidney composite outcome was sustained by approximately 18 months after randomization. CONCLUSIONS: These results emphasize a critical role of canagliflozin in kidney protection across a broad spectrum of participants with type 2 diabetes with varying levels of kidney function

Effects of newer kidney protective agents on kidney endpoints provide implications for future clinical trials

Doubling of serum creatinine (equivalent to a 57% decline in the estimated glomerular filtration rate (eGFR)) is an accepted component of a composite kidney endpoint in clinical trials. Smaller declines in eGFR (40%, 50%) have been applied in several recently conducted clinical trials. Here, we assessed the effects of newer kidney protective agents on endpoints including smaller proportional declines in eGFR to compare relative event rates and the magnitude of observed treatment effects. We performed a post hoc analysis of 4401 patients in the CREDENCE, 4304 in the DAPA-CKD, 5734 in the FIDELIO-DKD, and 3668 in the SONAR trials, which assessed the effects of canagliflozin, dapagliflozin, finerenone and atrasentan in patients with chronic kidney disease. Effects of active therapies versus placebo on alternative composite kidney endpoints incorporating different eGFR decline thresholds (40%, 50%, or 57% eGFR reductions from baseline) with kidney failure or death due to kidney failure were compared. Cox-proportional hazards regression models were used to assess and compare treatment effects. During follow-up, event rates were higher for endpoints incorporating smaller versus larger eGFR decline thresholds. Compared to the treatment effects on kidney failure or death due to kidney failure, the magnitude of relative treatment effects was generally similar when considering composite endpoints incorporating smaller declines in eGFR. Hazard ratios for the four interventions ranged from 0.63 to 0.82 for the endpoint incorporating 40% eGFR decline and 0.59 to 0.76 for the endpoint incorporating 57% eGFR decline. Clinical trials incorporating a 40% eGFR decline in a composite endpoint would require approximately half the number of participants compared to a 57% eGFR decline with equivalent statistical power. Thus, in populations at high risk of CKD progression, the relative effects of newer kidney protective therapies appear generally similar across endpoints based on varying eGFR decline thresholds.</p

Effect of Canagliflozin on Renal and Cardiovascular Outcomes across Different Levels of Albuminuria:Data from the CANVAS Program

Background If SGLT2 inhibitors protect the kidneys by reducing albuminuria as hypothesized, peoplewith type 2 diabetes mellitus (T2DM) with higher albuminuria should benefit more. Methods We conducted a post-hoc analysis of data from the CANagliflozin cardioVascular Assessment Study (CANVAS) Program, which randomized 10,142 participants with T2DM and high cardiovascular risk to canagliflozin or placebo. We assessed effects of canagliflozin on renal, cardiovascular, and safety outcomes by baseline albuminuria. The trial included 2266 participants (22.3%) with moderately increased albuminuria (urinary albumin/creatinine ratio [UACR] 30-300mg/g) and 760 (7.5%) with severely increased albuminuria (UACR .300 mg/g) at baseline. Results Canagliflozin lowered albuminuria with greater proportional reductions in those with moderately and severely increased albuminuria (P heterogeneity,0.001). After week 13, canagliflozin slowed the annual loss of kidney function across albuminuria subgroups, with greater absolute reductions in participants with severely increased albuminuria (placebo-subtracted difference 3.01 ml/min per 1.73 m2 per year; P heterogeneity,0.001). Heterogeneity for the renal composite outcome of 40%reduction in EGFR, ESKD, or renal-related death was driven by lesser effects in participants with moderately increased albuminuria (P heterogeneity=0.03), but no effectmodification was observed when albuminuria was fitted as a continuous variable (P heterogeneity=0.94). Cardiovascular and safety outcomes were mostly consistent across albuminuria levels including increased risks for amputation across albuminuria subgroups (P heterogeneity= 0.66). Greater absolute risk reductions in the renal composite outcome were observed in participants with severely increased albuminuria (P heterogeneity=0.004). Conclusions The proportional effects of canagliflozin on renal and cardiovascular outcomes are mostly consistent across patients with different levels of albuminuria, but absolute benefits are greatest among those with severely increased albuminuria