Effects of empagliflozin in patients with chronic kidney disease from Japan: exploratory analyses from EMPA-KIDNEY

BACKGROUND

EMPA-KIDNEY assessed the effects of empagliflozin 10 mg once daily vs. placebo in 6609 patients with chronic kidney disease (CKD) at risk of progression, including 612 participants from Japan.

METHODS

Eligibility required an estimated glomerular filtration rate (eGFR) of ≥ 20 < 45; or ≥ 45 < 90 ml/min/1.73m2 with a urinary albumin-to-creatinine ratio (uACR) of ≥ 200 mg/g. The primary outcome was a composite of kidney disease progression (end-stage kidney disease, a sustained eGFR decline to < 10 ml/min/1.73m2 or ≥ 40% from randomization, or renal death) or cardiovascular death. In post-hoc analyses, we explored the effects of empagliflozin in participants from Japan vs. non-Japan regions, including additional models assessing whether differences in treatment effects between these regions could result from differences in baseline characteristics.

RESULTS

Japanese participants had higher levels of albuminuria and eGFR than those from non-Japan regions. During a median of 2.0 year follow-up, a primary outcome occurred in 432 patients (13.1%) in the empagliflozin group and in 558 patients (16.9%) in the placebo group (hazard ratio [HR], 0.72, 95% confidence interval [95%CI] 0.64-0.82; P < 0.0001). Among the participants from non-Japan regions, there were 399 vs. 494 primary outcomes (0.75, 0.66-0.86), and 33 vs. 64 (0.49, 0.32-0.75; heterogeneity p = 0.06) in Japan. Results were similar when models explicitly considered treatment interactions with diabetes status, categories of eGFR/uACR, and recruitment in Japan (heterogeneity p = 0.08). Safety outcomes were broadly comparable between the two groups, and by Japanese status.

CONCLUSIONS

Empagliflozin safely reduced the risk of "kidney disease progression or cardiovascular death" in patients with CKD, with consistent effects in participants from Japan.

Effects of Empagliflozin on Fluid Overload, Weight, and Blood Pressure in CKD

SIGNIFICANCE STATEMENT

SGLT2 inhibitors reduce risk of kidney progression, AKI, and cardiovascular disease, but the mechanisms of benefit are incompletely understood. Bioimpedance spectroscopy can estimate body water and fat mass. One quarter of the EMPA-KIDNEY bioimpedance substudy CKD population had clinically significant levels of bioimpedance-derived "Fluid Overload" at recruitment. Empagliflozin induced a prompt and sustained reduction in "Fluid Overload," irrespective of sex, diabetes, and baseline N-terminal pro B-type natriuretic peptide or eGFR. No significant effect on bioimpedance-derived fat mass was observed. The effects of SGLT2 inhibitors on body water may be one of the contributing mechanisms by which they mediate effects on cardiovascular risk.

BACKGROUND

CKD is associated with fluid excess that can be estimated by bioimpedance spectroscopy. We aimed to assess effects of sodium glucose co-transporter 2 inhibition on bioimpedance-derived "Fluid Overload" and adiposity in a CKD population.

METHODS

EMPA-KIDNEY was a double-blind placebo-controlled trial of empagliflozin 10 mg once daily in patients with CKD at risk of progression. In a substudy, bioimpedance measurements were added to the main trial procedures at randomization and at 2- and 18-month follow-up visits. The substudy's primary outcome was the study-average difference in absolute "Fluid Overload" (an estimate of excess extracellular water) analyzed using a mixed model repeated measures approach.

RESULTS

The 660 substudy participants were broadly representative of the 6609-participant trial population. Substudy mean baseline absolute "Fluid Overload" was 0.4±1.7 L. Compared with placebo, the overall mean absolute "Fluid Overload" difference among those allocated empagliflozin was -0.24 L (95% confidence interval [CI], -0.38 to -0.11), with similar sized differences at 2 and 18 months, and in prespecified subgroups. Total body water differences comprised between-group differences in extracellular water of -0.49 L (95% CI, -0.69 to -0.30, including the -0.24 L "Fluid Overload" difference) and a -0.30 L (95% CI, -0.57 to -0.03) difference in intracellular water. There was no significant effect of empagliflozin on bioimpedance-derived adipose tissue mass (-0.28 kg [95% CI, -1.41 to 0.85]). The between-group difference in weight was -0.7 kg (95% CI, -1.3 to -0.1).

CONCLUSIONS

In a broad range of patients with CKD, empagliflozin resulted in a sustained reduction in a bioimpedance-derived estimate of fluid overload, with no statistically significant effect on fat mass.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03594110 ; EuDRACT: 2017-002971-24 ( https://eudract.ema.europa.eu/ ).

Efficacy and safety of aldosterone synthase inhibition with and without empagliflozin for chronic kidney disease: a randomised, controlled, phase 2 trial

BACKGROUND

Excess aldosterone accelerates chronic kidney disease progression. This phase 2 clinical trial assessed BI 690517, an aldosterone synthase inhibitor, for efficacy, safety, and dose selection.

METHODS

This was a multinational, randomised, controlled, phase 2 trial. People aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 30 to less than 90 mL/min/1·73 m2, a urine albumin to creatinine ratio (UACR) of 200 to less than 5000 mg/g, and serum potassium of 4·8 mmol/L or less, taking an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, were enrolled. Participants were randomly assigned (1:1) to 8 weeks of empagliflozin or placebo run-in, followed by a second randomisation (1:1:1:1) to 14 weeks of treatment with once per day BI 690517 at doses of 3 mg, 10 mg, or 20 mg, or placebo. Study participants, research coordinators, investigators, and the data coordinating centre were masked to treatment assignment. The primary endpoint was the change in UACR measured in first morning void urine from baseline (second randomisation) to the end of treatment. This study is registered with ClinicalTrials.gov (NCT05182840) and is completed.

FINDINGS

Between Feb 18 and Dec 30, 2022, of the 714 run-in participants, 586 were randomly assigned to receive BI 690517 or placebo. At baseline, 33% (n=196) were women, 67% (n=390) were men, 42% (n=244) had a racial identity other than White, and mean participant age was 63·8 years (SD 11·3). Mean baseline eGFR was 51·9 mL/min/1·73 m2 (17·7) and median UACR was 426 mg/g (IQR 205 to 889). Percentage change in first morning void UACR from baseline to the end of treatment at week 14 was -3% (95% CI -19 to 17) with placebo, -22% (-36 to -7) with BI 690517 3 mg, -39% (-50 to -26) with BI 690517 10 mg, and -37% (-49 to -22) with BI 690517 20 mg monotherapy. BI 690517 produced similar UACR reductions when added to empagliflozin. Investigator-reported hyperkalaemia occurred in 10% (14/146) of those in the BI 690517 3 mg group, 15% (22/144) in the BI 690517 10 mg group, and 18% (26/146) in the BI 690517 20 mg group, and in 6% (nine of 147) of those receiving placebo, with or without empagliflozin. Most participants with hyperkalaemia did not require intervention (86% [72/84]). Adrenal insufficiency was an adverse event of special interest reported in seven of 436 study participants (2%) receiving BI 690517 and one of 147 participants (1%) receiving matched placebo. No treatment-related deaths occurred during the study.

INTERPRETATION

BI 690517 dose-dependently reduced albuminuria with concurrent renin-angiotensin system inhibition and empagliflozin, suggesting an additive efficacy for chronic kidney disease treatment without unexpected safety signals.

FUNDING

Boehringer Ingelheim.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Methods Article for a Study Protocol: Study Design and Baseline Characteristics for Aldosterone Synthase Inhibition in Chronic Kidney Disease

INTRODUCTION

Aldosterone synthase (AS) inhibition may overcome increased aldosterone production in response to renin-angiotensin system inhibition. BI 690517 is an AS inhibitor under investigation for chronic kidney disease (CKD).

METHODS

This multinational, phase II, double-blind study (NCT05182840) investigated the efficacy and safety of daily oral BI 690517, with or without empagliflozin 10 mg, in participants with CKD. The primary endpoint was change from baseline in urine albumin:creatinine ratio (UACR) at week 14. Between February 18, 2022, and December 30, 2022, 714 adults already treated by angiotensin-converting enzyme inhibitor (30.5%) or angiotensin receptor blocker (69.8%) were randomized (1:1) to an 8-week run-in to assign background empagliflozin (n = 356) or placebo (n = 358). Participants in each group were then randomized (1:1:1:1) to a 14-week treatment period with BI 690517 (3 mg, 10 mg, or 20 mg) or placebo. Of the 714 participants who entered run-in, 586 were randomized to the treatment period. They were predominantly men (66.6%) of white race (58.4%) with a mean (standard deviation [SD]) age of 63.8 (11.3) years. Type 2 diabetes was present in 414 participants (70.6%). The baseline mean (SD) estimated glomerular filtration rate was 51.9 (17.7) mL/min/1.73 m2, and median (interquartile range) UACR was 426.3 mg/g (205.3-888.5).

CONCLUSION

This study will inform dose selection for further clinical development and determine whether BI 690517, with or without background empagliflozin, has a favorable safety profile and potential for additive kidney protection in participants with CKD already treated with a renin-angiotensin system inhibitor.

Changes in cardiac and vascular haemodynamics as potential mediators of improvements in cardiovascular and kidney outcomes with empagliflozin in type 2 diabetes

AIMS

Evaluate changes in haemodynamic markers as mediators of cardiovascular (CV) and kidney benefits with empagliflozin.

METHODS

Post-hoc analysis of EMPA-REG OUTCOME in patients with type 2 diabetes (T2D) and established CV disease receiving empagliflozin (10 and 25 mg) or placebo. Outcomes were CV death, hospitalisation for heart failure [HF], HF death, incident/worsening nephropathy, new onset macroalbuminuria, and the composite of sustained estimated glomerular filtration rate decline ≥40 % from baseline, renal replacement therapy or renal death. To be considered a mediator, changes in variable (pulse pressure, mean arterial pressure and cardiac workload) over time had to be (1) affected by active treatment, (2) associated with the outcome, and (3) adjustment for changes over time must reduce treatment effect versus an unadjusted analysis. Variables were evaluated in Cox regression analyses.

RESULTS

Pulse pressure, mean arterial pressure and cardiac workload were significantly reduced by empagliflozin vs placebo. Using change from baseline to Week 12 or sensitivity analyses (time-dependent updated mean and current change from baseline) of these CV parameters, only small impacts on empagliflozin effect on CV and kidney outcomes were shown.

CONCLUSIONS

Improvements in haemodynamic parameters did not substantially mediate empagliflozin benefits on CV and kidney outcomes in patients with T2DM and established CV disease.

Empagliflozin in Patients with Chronic Kidney Disease

BACKGROUND

The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients.

METHODS

We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m² of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m² with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to <10 ml per minute per 1.73 m², a sustained decrease in eGFR of ≥40% from baseline, or death from renal causes) or death from cardiovascular causes.

RESULTS

A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P<0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P = 0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups.

CONCLUSIONS

Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo. (Funded by Boehringer Ingelheim and others; EMPA-KIDNEY ClinicalTrials.gov number, NCT03594110; EudraCT number, 2017-002971-24.).

Impact of diabetes on the effects of sodium glucose co-transporter-2 inhibitors on kidney outcomes: collaborative meta-analysis of large placebo-controlled trials

BACKGROUND

Large trials have shown that sodium glucose co-transporter-2 (SGLT2) inhibitors reduce the risk of adverse kidney and cardiovascular outcomes in patients with heart failure or chronic kidney disease, or with type 2 diabetes and high risk of atherosclerotic cardiovascular disease. None of the trials recruiting patients with and without diabetes were designed to assess outcomes separately in patients without diabetes.

METHODS

We did a systematic review and meta-analysis of SGLT2 inhibitor trials. We searched the MEDLINE and Embase databases for trials published from database inception to Sept 5, 2022. SGLT2 inhibitor trials that were double-blind, placebo-controlled, performed in adults (age ≥18 years), large (≥500 participants per group), and at least 6 months in duration were included. Summary-level data used for analysis were extracted from published reports or provided by trial investigators, and inverse-variance-weighted meta-analyses were conducted to estimate treatment effects. The main efficacy outcomes were kidney disease progression (standardised to a definition of a sustained ≥50% decrease in estimated glomerular filtration rate [eGFR] from randomisation, a sustained low eGFR, end-stage kidney disease, or death from kidney failure), acute kidney injury, and a composite of cardiovascular death or hospitalisation for heart failure. Other outcomes were death from cardiovascular and non-cardiovascular disease considered separately, and the main safety outcomes were ketoacidosis and lower limb amputation. This study is registered with PROSPERO, CRD42022351618.

FINDINGS

We identified 13 trials involving 90 413 participants. After exclusion of four participants with uncertain diabetes status, we analysed 90 409 participants (74 804 [82·7%] participants with diabetes [>99% with type 2 diabetes] and 15 605 [17·3%] without diabetes; trial-level mean baseline eGFR range 37-85 mL/min per 1·73 m2). Compared with placebo, allocation to an SGLT2 inhibitor reduced the risk of kidney disease progression by 37% (relative risk [RR] 0·63, 95% CI 0·58-0·69) with similar RRs in patients with and without diabetes. In the four chronic kidney disease trials, RRs were similar irrespective of primary kidney diagnosis. SGLT2 inhibitors reduced the risk of acute kidney injury by 23% (0·77, 0·70-0·84) and the risk of cardiovascular death or hospitalisation for heart failure by 23% (0·77, 0·74-0·81), again with similar effects in those with and without diabetes. SGLT2 inhibitors also reduced the risk of cardiovascular death (0·86, 0·81-0·92) but did not significantly reduce the risk of non-cardiovascular death (0·94, 0·88-1·02). For these mortality outcomes, RRs were similar in patients with and without diabetes. For all outcomes, results were broadly similar irrespective of trial mean baseline eGFR. Based on estimates of absolute effects, the absolute benefits of SGLT2 inhibition outweighed any serious hazards of ketoacidosis or amputation.

INTERPRETATION

In addition to the established cardiovascular benefits of SGLT2 inhibitors, the randomised data support their use for modifying risk of kidney disease progression and acute kidney injury, not only in patients with type 2 diabetes at high cardiovascular risk, but also in patients with chronic kidney disease or heart failure irrespective of diabetes status, primary kidney disease, or kidney function.

FUNDING

UK Medical Research Council and Kidney Research UK.

Safety of Empagliflozin in Patients With Type 2 Diabetes and Chronic Kidney Disease: Pooled Analysis of Placebo-Controlled Clinical Trials

OBJECTIVE

To assess the safety of empagliflozin in patients with type 2 diabetes and moderate to severe chronic kidney disease (CKD) (category G3-4) enrolled in clinical trials.

RESEARCH DESIGN AND METHODS

This analysis pooled data from 19 randomized, placebo-controlled, phase 1-4 clinical trials and 1 randomized, placebo-controlled extension study in which patients received empagliflozin 10 mg or 25 mg daily. Time to first occurrence of adverse events (AEs) was evaluated using Kaplan-Meier analysis and multivariable Cox regression models.

RESULTS

Among a total of 15,081 patients who received at least one study drug dose, 1,522, 722, and 123 were classified as having G3A, G3B, and G4 CKD, respectively, at baseline. Demographic and clinical characteristics were similar between treatment groups across CKD categories. Rates of serious AEs, AEs leading to discontinuation, and events of special interest (including lower limb amputations and acute renal failure [ARF]) were also similar between empagliflozin and placebo across CKD subgroups. In adjusted Cox regression analyses, risks for volume depletion and ARF were similar for empagliflozin and placebo in the combined group with CKD categories G3B and G4 and the G3A group. Notably lower risks were observed in both groups for hyperkalemia (hazard ratio 0.59 [95% CI 0.37-0.96, P = 0.0323] and 0.48 [0.26-0.91, P = 0.0243], respectively) and edema (0.47 [0.33-0.68, P < 0.0001] and 0.44 [0.28-0.68, P = 0.0002], respectively).

CONCLUSIONS

Use of empagliflozin in patients with type 2 diabetes and advanced CKD raised no new safety concerns and may have beneficial effects on the development of hyperkalemia and edema.

Consistent effects of empagliflozin on cardiovascular and kidney outcomes irrespective of diabetic kidney disease categories: Insights from the EMPA-REG OUTCOME trial

AIM

To explore the cardiovascular (CV) and kidney effects of empagliflozin in patients with different clinical phenotypes of diabetic kidney disease (DKD) (i.e. with the presence or absence of overt albuminuria) participating in the EMPA-REG OUTCOME trial.

MATERIALS AND METHODS

EMPA-REG OUTCOME randomized participants (1:1:1) to empagliflozin 10 mg, 25 mg or placebo, added to standard of care. Post hoc, patients with different clinical phenotypes of DKD at baseline were categorized in three subgroups: (a) overt DKD (overt albuminuria [urinary albumin-to-creatinine ratio of >300 mg/g] with any estimated glomerular filtration rate [eGFR]; n = 769); (b) non-overt DKD (kidney impairment [eGFR < 60 mL/min/1.73 m² ] without overt albuminuria [urinary albumin-to-creatinine ratio of ≤300 mg/g]; n = 1290); and (c) 'all others' (eGFR ≥ 60 mL/min/1.73 m² without overt albuminuria; n = 4893). Analyses included CV (death, hospitalization for heart failure, all-cause hospitalization) and selected kidney outcomes, change in eGFR and kidney safety. Cox proportional hazards models assessed the consistency of treatment effect across subgroups.

RESULTS

Empagliflozin significantly reduced the risk of CV and kidney outcomes across all subgroups (P-values for interaction >.05), consistent with the overall trial population findings. Empagliflozin also significantly reduced the yearly loss of eGFR, assessed by chronic slopes, in all subgroups. The adverse event profile of empagliflozin was similar across all subgroups.

CONCLUSIONS

Empagliflozin may improve CV and kidney outcomes and slow the progression of kidney disease in type 2 diabetes patients with DKD, irrespective of its clinical form, both with or without the presence of overt albuminuria.

Kidney disease progression and all-cause mortality across estimated glomerular filtration rate and albuminuria categories among patients with vs. without type 2 diabetes

BACKGROUND

Studies of progression of kidney dysfunction typically focus on renal replacement therapy or percentage decline in estimated glomerular filtration rate (eGFR) as outcomes. Our aim was to compare real-world patients with and without T2D to estimate progression from and to clinically defined categories of kidney disease and all-cause mortality.

METHODS

This was an observational cohort study of 31,931 patients with and 33,201 age/sex matched patients without type 2 diabetes (T2D) who had a serum creatinine and urine albumin-to-creatinine ratio (UACR) or dipstick proteinuria (DP) values. We used the first available serum creatinine value between 2006 and 2012 to calculate baseline eGFR and categorized them and the corresponding UACR/DP values using the Kidney Disease Improving Global Outcomes (KDIGO) categories. To assess our primary outcomes, we extracted probabilities of eGFR progression or mortality from life-table analyses and conducted multivariable Cox regression analyses of relative risk adjusted for age, sex, race/ethnicity, smoking, ischemic heart disease, heart failure, and use of renal-angiotensin-aldosterone system inhibitors.

RESULTS

Patterns of eGFR decline were comparable among patients with vs. without T2D with larger percentage declines at higher albuminuria levels across all eGFR categories. eGFR decline was generally larger among T2D patients, particularly in those with severely increased albuminuria. Across all CKD categories, risk of progression to the next higher category of eGFR was substantially increased with increasing albuminuria. For example, the risk was 23.5, 36.2, and 65.1% among T2D patients with eGFR 30-59 ml/min/1.73m2 and UACR < 30, 30-299, and > 300 mg/dL, respectively (p < 0.001). Other comparisons were similarly significant. Among patients with low eGFR and normal to mildly increased albuminuria, the relative risk was up to 8-fold greater for all-cause mortality compared with the non-CKD subgroup (eGFR> 60 ml/min/1.73m2 with normal to mildly increased albuminuria).

CONCLUSIONS

Presence of albuminuria was associated with accelerated eGFR decline independent of T2D. Risk for adverse outcomes was remarkably high among patients with CKD and normal to mildly increased albuminuria levels. Independent of T2D or albuminuria, a substantial risk for adverse outcomes exists for CKD patients in a routine care setting.

Erratum: The potential for improving cardio-renal outcomes by sodium-glucose co-transporter-2 inhibition in people with chronic kidney disease: a rationale for the EMPA-KIDNEY study

[This corrects the article DOI: 10.1093/ckj/sfy090.].

Methylglyoxal down-regulates the expression of cell cycle associated genes and activates the p53 pathway in human umbilical vein endothelial cells

Although methylglyoxal (MGO) has emerged as key mediator of diabetic microvascular complications, the influence of MGO on the vascular transcriptome has not thoroughly been assessed. Since diabetes is associated with low grade inflammation causing sustained nuclear factor-kappa B (NF-κB) activation, the current study addressed 1) to what extent MGO changes the transcriptome of human umbilical vein endothelial cells (HUVECs) exposed to an inflammatory milieu, 2) what are the dominant pathways by which these changes occur and 3) to what extent is this affected by carnosine, a putative scavenger of MGO. Microarray analysis revealed that exposure of HUVECs to high MGO concentrations significantly changes gene expression, characterized by prominent down-regulation of cell cycle associated genes and up-regulation of heme oxygenase-1 (HO-1). KEGG-based pathway analysis identified six significantly enriched pathways of which the p53 pathway was the most affected. No significant enrichment of inflammatory pathways was found, yet, MGO did inhibit VCAM-1 expression in Western blot analysis. Carnosine significantly counteracted MGO-mediated changes in a subset of differentially expressed genes. Collectively, our results suggest that MGO initiates distinct transcriptional changes in cell cycle/apoptosis genes, which may explain MGO toxicity at high concentrations. MGO did not augment TNF-α induced inflammation.

Carnosinase concentration, activity, and CNDP1 genotype in patients with type 2 diabetes with and without nephropathy

This study assessed if serum carnosinase (CNDP1) activity and concentration in patients with type 2 diabetes mellitus (T2D) with diabetic nephropathy (DN) differs from those without nephropathy. In a cross-sectional design 127 patients with T2D with DN ((CTG)₅ homozygous patients n = 45) and 145 patients with T2D without nephropathy ((CTG)₅ homozygous patients n = 47) were recruited. Univariate and multivariate regression analyses were performed to predict factors relevant for serum CNDP1 concentration. CNDP1 (CTG)₅ homozygous patients with T2D with DN had significantly lower CNDP1 concentrations (30.4 ± 18.3 vs 51.2 ± 17.6 µg/ml, p < 0.05) and activity (1.25 ± 0.5 vs 2.53 ± 1.1 µmol/ml/h, p < 0.05) than those without nephropathy. This applied for patients with DN on the whole, irrespective of (CTG)₅ homozygosity. In the multivariate regression analyses, lower serum CNDP1 concentrations correlated with impaired renal function and to a lesser extend with the CNDP1 genotype (95% CI of regression coefficients: eGFR: 0.10-1.94 (p = 0.001); genotype: - 0.05 to 5.79 (p = 0.055)). Our study demonstrates that serum CNDP1 concentrations associate with CNDP1 genotype and renal function in patients with T2D. Our data warrant further studies using large cohorts to confirm these findings and to delineate the correlation between low serum CNDP1 concentrations and renal function deterioration in patients with T2D.

Serum Carnosinase-1 and Albuminuria Rather than the CNDP1 Genotype Correlate with Urinary Carnosinase-1 in Diabetic and Nondiabetic Patients with Chronic Kidney Disease

BACKGROUND

Carnosinase-1 (CN-1) can be detected in 24 h urine of healthy individuals and patients with type 2 diabetes (T2DM). We aimed to assess whether urinary CN-1 is also reliably measured in spot urine and investigated its association with renal function and the albumin/creatinine ratio (ACR). We also assessed associations between the CNDP1 (CTG) _n genotype and CN-1 concentrations in serum and urine.

METHODS

Patients with T2DM (n = 85) and nondiabetic patients with chronic kidney disease (CKD) (n = 26) stratified by albuminuria (ACR ≤ 300 mg/g or ACR > 300 mg/g) recruited from the nephrology clinic and healthy subjects (n = 24) were studied.

RESULTS

Urinary CN-1 was more frequently detected and displayed higher concentrations in patients with ACR > 300 mg/g as compared to those with ACR ≤ 300 mg/g irrespective of the baseline disease (T2DM: 554 ng/ml [IQR 212-934 ng/ml] vs. 31 ng/ml [IQR 31-63 ng/ml] (p < 0.0001) and nondiabetic CKD: 197 ng/ml [IQR 112-739] vs. 31 ng/ml [IQR 31-226 ng/ml] (p = 0.015)). A positive correlation between urinary CN-1 and ACR was found (r = 0.68, p < 0.0001). Multivariate linear regression analysis revealed that ACR and serum CN-1 concentrations but not eGFR or the CNDP1 genotype are independent predictors of urinary CN-1, explaining 47% of variation of urinary CN-1 concentrations (R ² = 0.47, p < 0.0001).

CONCLUSION

These results confirm and extend previous findings on urinary CN-1 concentrations, suggesting that assessment of CN-1 in spot urine is as reliable as in 24 h urine and may indicate that urinary CN-1 in macroalbuminuric patients is primarily serum-derived and not locally produced.

The potential for improving cardio-renal outcomes by sodium-glucose co-transporter-2 inhibition in people with chronic kidney disease: a rationale for the EMPA-KIDNEY study

Diabetes is a common cause of chronic kidney disease (CKD), but in aggregate, non-diabetic diseases account for a higher proportion of cases of CKD than diabetes in many parts of the world. Inhibition of the renin–angiotensin system reduces the risk of kidney disease progression and treatments that lower blood pressure (BP) or low-density lipoprotein cholesterol reduce cardiovascular (CV) risk in this population. Nevertheless, despite such interventions, considerable risks for kidney and CV complications remain. Recently, large placebo-controlled outcome trials have shown that sodium-glucose co-transporter-2 (SGLT-2) inhibitors reduce the risk of CV disease (including CV death and hospitalization for heart failure) in people with type 2 diabetes who are at high risk of atherosclerotic disease, and these effects were largely independent of improvements in hyperglycaemia, BP and body weight. In the kidney, increased sodium delivery to the macula densa mediated by SGLT-2 inhibition has the potential to reduce intraglomerular pressure, which may explain why SGLT-2 inhibitors reduce albuminuria and appear to slow kidney function decline in people with diabetes. Importantly, in the trials completed to date, these benefits appeared to be maintained at lower levels of kidney function, despite attenuation of glycosuric effects, and did not appear to be dependent on ambient hyperglycaemia. There is therefore a rationale for studying the cardio-renal effects of SGLT-2 inhibition in people at risk of CV disease and hyperfiltration (i.e. those with substantially reduced nephron mass and/or albuminuria), irrespective of whether they have diabetes.

The association between estimated glomerular filtration rate, albuminuria, and risk of cardiovascular hospitalizations and all-cause mortality among patients with type 2 diabetes

AIMS

We evaluated the simultaneous effects of all clinically recognized categories of albuminuria and estimated glomerular filtration rate (eGFR) on cardiovascular disease (CVD) and mortality METHODS: We conducted a longitudinal observational study of 16,678 type 2 diabetes (T2D) patients. From the first serum creatinine value from 2006 to 2012 and a urine-albumin creatinine ratio (UACR) recorded within 6months, we applied baseline Kidney Disease: Improving Global Outcomes (KDIGO) categories of eGFR and albuminuria. We followed patients for up to 11years to calculate adjusted incidence per 1000person-years (p-y) of first CVD hospitalization and all-cause mortality.

RESULTS

Over 98,069p-y of follow-up, CVD hospitalization risk was greater for each higher eGFR and albuminuria category. In eGFR category G2 (60-89mL/min/1.73m2), adjusted incidence per 1000p-y was 14.1 (95% CI 12.9-15.5), 19.8 (17.2-22.8), and 22.8 (17.4-30.0) for normoalbuminuria, microalbuminuria and macroalbuminuria, respectively. For eGFR category G3a (45-59), rates were 26.7 (22.3-32.0), 40.3 (32.2-50.5), and 44.1 (28.8-67.4), respectively. Adjusted risk of all-cause mortality followed a similar pattern.

CONCLUSIONS

Our data underscore the importance of including detailed eGFR and UACR values in assessing CVD risk. High albuminuria and low eGFR is a potent predictor of CVD and death.

Carnosine Attenuates the Development of both Type 2 Diabetes and Diabetic Nephropathy in BTBR ob/ob Mice

We previously demonstrated that polymorphisms in the carnosinase-1 gene (CNDP1) determine the risk of nephropathy in type 2 diabetic patients. Carnosine, the substrate of the enzyme encoded by this gene, is considered renoprotective and could possibly be used to treat diabetic nephropathy (DN). In this study, we examined the effect of carnosine treatment in vivo in BTBR (Black and Tan, BRachyuric) ob/ob mice, a type 2 diabetes model which develops a phenotype that closely resembles advanced human DN. Treatment of BTBR ob/ob mice with 4 mM carnosine for 18 weeks reduced plasma glucose and HbA1c, concomitant with elevated insulin and C-peptide levels. Also, albuminuria and kidney weights were reduced in carnosine-treated mice, which showed less glomerular hypertrophy due to a decrease in the surface area of Bowman's capsule and space. Carnosine treatment restored the glomerular ultrastructure without affecting podocyte number, resulted in a modified molecular composition of the expanded mesangial matrix and led to the formation of carnosine-acrolein adducts. Our results demonstrate that treatment with carnosine improves glucose metabolism, albuminuria and pathology in BTBR ob/ob mice. Hence, carnosine could be a novel therapeutic strategy to treat patients with DN and/or be used to prevent DN in patients with diabetes.

The CNDP1 (CTG)5 Polymorphism Is Associated with Biopsy-Proven Diabetic Nephropathy, Time on Hemodialysis, and Diabetes Duration

Considering that the homozygous CNDP1 (CTG)₅ genotype affords protection against diabetic nephropathy (DN) in female patients with type 2 diabetes, this study assessed if this association remains gender-specific when applying clinical inclusion criteria (CIC-DN) or biopsy proof (BP-DN). Additionally, it assessed if the prevalence of the protective genotype changes with diabetes duration and time on hemodialysis and if this occurs in association with serum carnosinase (CN-1) activity. Whereas the distribution of the (CTG)₅ homozygous genotype in the no-DN and CIC-DN patients was comparable, a lower frequency was found in the BP-DN patients, particularly in females. We observed a significant trend towards high frequencies of the (CTG)₅ homozygous genotype with increased time on dialysis. This was also observed for diabetes duration but only reached significance when both (CTG)₅ homo- and heterozygous patients were included. CN-1 activity negatively correlated with time on hemodialysis and was lower in (CTG)₅ homozygous patients. The latter remained significant in female subjects after gender stratification. We confirm the association between the CNDP1 genotype and DN to be likely gender-specific. Although our data also suggest that (CTG)₅ homozygous patients may have a survival advantage on dialysis and in diabetes, this hypothesis needs to be confirmed in a prospective cohort study.

Hyperglycemia Does Not Affect Iron Mediated Toxicity of Cultured Endothelial and Renal Tubular Epithelial Cells: Influence of L-Carnosine

Iron has been suggested to affect the clinical course of type 2 diabetes (T2DM) as accompanying increased intracellular iron accumulation may provide an alternative source for reactive oxygen species (ROS). Although carnosine has proven its therapeutic efficacy in rodent models of T2DM, little is known about its efficacy to protect cells from iron toxicity. We sought to assess if high glucose (HG) exposure makes cultured human umbilical vein endothelial cells (HUVECs) and renal proximal tubular epithelial cells (PTECs) more susceptible to metal induced toxicity and if this is ameliorated by L-carnosine. HUVECs and PTECs, cultured under normal glucose (5 mM, NG) or HG (30 mM), were challenged for 24 h with FeCl3. Cell viability was not impaired under HG conditions nor did HG increase susceptibility to FeCl3. HG did not change the expression of divalent metal transporter 1 (DMT1), ferroportin (IREG), and transferrin receptor protein 1 (TFRC). Irrespective of glucose concentrations L-carnosine prevented toxicity in a dose-dependent manner, only if it was present during the FeCl3 challenge. Hence our study indicates that iron induced cytotoxicity is not enhanced under HG conditions. L-Carnosine displayed a strong protective effect, most likely by chelation of iron mediated toxicity.

Different conformational forms of serum carnosinase detected by a newly developed sandwich ELISA for the measurements of carnosinase concentrations

Serum carnosinase (CN-1) measurements are at present mainly performed by assessing enzyme activity. This method is time-consuming, not well suited for large series of samples and can be discordant to measurements of CN-1 protein concentrations. To overcome these limitations, we developed sandwich ELISA assays using different anti-CN-1 antibodies, i.e., ATLAS (polyclonal IgG) and RYSK173 (monoclonal IgG1). With the ATLAS-based assay, similar amounts of CN-1 were detected in serum and both EDTA and heparin plasma. The RYSKS173-based assay detected CN-1 in serum in all individuals at significantly lower concentrations compared to the ATLAS-based assay (range: 0.1-1.8 vs. 1-50 μg/ml, RYSK- vs. ATLAS-based, P<0.01). CN-1 detection with the RYSK-based assay was increased in EDTA plasma, albeit at significantly lower concentrations compared to ATLAS. In heparin plasma, CN-1 was also poorly detected with the RYSK-based assay. Addition of DTT to serum increased the detection of CN-1 in the RYSK-based assay almost to the levels found in the ATLAS-based assay. Both ELISA assays were highly reproducible (R: 0.99, P<0.01 and R: 0.93, P<0.01, for the RYSK- and ATLAS-based assays, respectively). Results of the ATLAS-based assay showed a positive correlation with CN-1 activity (R: 0.62, P<0.01), while this was not the case for the RYSK-based assay. However, there was a negative correlation between CN-1 activity and the proportion of CN-1 detected in the RYSK-based assay, i.e., CN-1 detected with the RYSK-based assay/CN-1 detected with the ATLAS-based assay × 100% (Spearman-Rang correlation coefficient: -0.6, P<0.01), suggesting that the RYSK-based assay most likely detects a CN-1 conformation with low CN-1 activity. RYSK173 and ATLAS antibodies reacted similarly in Western blot, irrespective of PNGase treatment. Binding of RYSK173 in serum was not due to differential N-glycosylation as demonstrated by mutant CN-1 cDNA constructs. In conclusion, our study demonstrates a good correlation between enzyme activity and CN-1 protein concentration in ELISA and suggests the presence of different CN-1 conformations in serum. The relevance of these different conformations is still elusive and needs to be addressed in further studies.