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.

Development of CYP11B1 and CYP11B2 assays utilizing homogenates of adrenal glands: Utility of monkey as a surrogate for human

Elevated levels of aldosterone are associated with arterial hypertension, congestive heart failure, chronic kidney disease, and obesity. Aldosterone is produced predominantly in the zona glomerulosa of the cortex of the adrenal gland by the enzyme aldosterone synthase (CYP11B2). Treatment of the above indications by decreasing production of aldosterone is thought to be of therapeutic benefit by lessening the deleterious effects of aldosterone mediated through both the mineralocorticoid receptor and also through so called non-genomic pathways. However, inhibition of the highly similar enzyme, CYP11B1, which is responsible for the production of cortisol, must be avoided in the development of clinically useful aldosterone synthase inhibitors due to the resulting impairment of the cortisol-induced stress response. In efforts to assess the interactions of compounds with the CYP11B enzymes, a variety of cell-based inhibitor screening assays for both CYP11B1 and CYP11B2 have been reported. Herein we report details of assays employing both cynomolgus monkey adrenal homogenate (CAH) and human adrenal homogenate (HAH) as sources of CYP11B1 and CYP11B2 enzymes. Utilizing both CAH and HAH, we have characterized the kinetics of the CYP11B1-mediated conversion of 11-deoxycortisol to cortisol and the CYP11B2-mediated oxidation of corticosterone to aldosterone. Inhibition assays for both CYP11B1 and CYP11B2 were subsequently developed. Based on a comparison of human and monkey amino acid sequences, kinetics data, and inhibition values derived from the HAH and CAH assays, evidence is provided in support of using cynomolgus monkey tissue-derived cell homogenates as suitable surrogates for the human enzymes.

Pharmacokinetics and bioavailability of the isoflavone biochanin A in rats

Biochanin A (BCA) is a dietary isoflavone present in legumes, most notably red clover, and in many herbal dietary supplements. BCA has been reported to have chemopreventive properties and is metabolized to the isoflavone genistein (GEN), BCA conjugates, and GEN conjugates. The metabolites may contribute to the chemopreventive effects of BCA. The absorption, metabolism, and disposition of BCA have not been determined in rats. Our objective was to evaluate the pharmacokinetics and metabolism of BCA in rats. Male Sprague-Dawley rats were administered BCA by intravenous injection (1 and 5 mg/kg), by intraperitoneal injection (5 and 50 mg/kg), and orally (5 and 50 mg/kg). Plasma and bile samples were enzymatically hydrolyzed in vitro to determine conjugate concentrations for BCA and GEN. Equilibrium dialysis was used to determine protein binding. The BCA and GEN concentrations in plasma, urine, and bile were determined by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pharmacokinetic parameters of BCA were analyzed by noncompartmental analysis. Significant levels of BCA conjugates and GEN conjugates were detected in plasma and bile. Both BCA and GEN were found to have a high clearance and a large apparent volume of distribution; the bioavailability of both was poor (<4%). Reentry peaks were evident after oral administration of both BCA and GEN, suggesting enterohepatic cycling. The free fraction of BCA in rat plasma was 1.5%. A 2-compartment model that included both linear and nonlinear clearance terms and enterohepatic recirculation best described the plasma data. This represents the first evaluation of the dose-dependent pharmacokinetics and metabolism of BCA in rats.

The Citizenship Safety Project: a pilot study

The Government White Paper Saving Lives: Our Healthier Nation (1999) provides a clear indication that accidents are a serious public health problem and have been targeted by the Department of Health as a key area for prevention over the next 10 years. School-based injury prevention programmes have been identified as one of the key settings for the implementation of the White Paper's heath promotion strategies. The Citizen Safety Project (CSP) is a peer-delivered injury prevention programme for Year 10 students (14-15 years) and Year 2 pupils (6-7 years). This paper summarizes the findings of a pilot study that assessed the feasibility of implementing the CSP in schools and of conducting a larger study. Working as part of their Personal Social Health Education lessons, 11 pairs (n = 22) of Year 10 students developed a project to take one accident prevention theme of their choice into a primary school to teach small groups of five or six Year 2 pupils (n = 55). A formative evaluation was conducted, based on interviews with Year 2 and Year 10 teachers (n = 2), and the diaries of Year 10 students. Knowledge of accident prevention and risk awareness was measured in Year 2 pupils using the Draw and Write technique, and impact on Year 10 students was measured using self-esteem and locus of control inventories. Using both statistical and thematic analysis the study concludes that the CSP is well accepted, improves knowledge in Year 2 pupils and boosts confidence in Year 10 students, while concurrently achieving key stage attainment targets. Implications of the study are discussed in terms of future research, as are recommendations with regard to modifications to the project.

An evaluation of the effectiveness of the Injury Minimization Programme for Schools (IMPS)

OBJECTIVE

To evaluate the effect of an injury prevention programme (Injury Minimization Programme for Schools, IMPS) on children's primary and secondary prevention, and basic life support, knowledge, attitudes, skills, and behaviour.

DESIGN

Prospective non-randomised matched control.

SETTING

Radcliffe NHS Trust and primary and middle schools in Oxfordshire, UK.

SUBJECTS

1,200 year 6 children (10 and 11 years old); 600 received IMPS, a primary and secondary injury prevention programme taught in the school and hospital environments; 600 children in the control group received no planned intervention.

MAIN OUTCOME MEASURES

Safety knowledge, measured using a quiz. Resuscitation skills and behaviour observed and assessed using a simulated emergency scenario. Attitude and hypothetical behaviour towards safety assessed by the "draw and write" technique.

RESULTS

Before intervention, both groups had similar levels of knowledge. Five months after the intervention, significantly more IMPS trained children demonstrated a greater increase in knowledge in administering first aid and the correct procedure for making a call to the emergency services. They also demonstrated better basic life support techniques-for example, mouth-to-mouth and cardiac compressions. They identified more subtle dangers, were more likely to seek help, and tell others that their behaviour was dangerous.

CONCLUSION

The results demonstrate the benefits of the IMPS programme on injury prevention knowledge, attitudes, and behaviours.

Genetic mapping of a murine locus controlling development of T helper 1/T helper 2 type responses

Genetic background of the T cell can influence T helper (Th) phenotype development, with some murine strains (e.g., B10.D2) favoring Th1 development and others (e.g., BALB/c) favoring Th2 development. Recently we found that B10.D2 exhibit an intrinsically greater capacity to maintain interleukin 12 (IL-12) responsiveness under neutral conditions in vitro compared with BALB/c T cells, allowing for prolonged capacity to undergo IL-12-induced Th1 development. To begin identification of the loci controlling this genetic effect, we used a T-cell antigen receptor-transgenic system for in vitro analysis of intercrosses between BALB/c and B10.D2 mice and have identified a locus on murine chromosome 11 that controls the maintenance of IL-12 responsiveness, and therefore the subsequent Th1/Th2 response. This chromosomal region is syntenic with a locus on human chromosome 5q31.1 shown to be associated with elevated serum IgE levels, suggesting that genetic control of Th1/Th2 differentiation in mouse, and of atopy development in humans, may be expressed through similar mechanisms.

Localization of the mouse gene releasing sex-limited expression of Slp

To probe genetic variation in the regulation of sexual dimorphism, we have characterized the mouse protein Slp, coded by the gene sex-limited protein (Slp). Slp expression in many strains is limited to males and is androgen-dependent. However, female expression is also observed in rare strains, due to nonlinked gene(s) termed regulator of sex-limitation (rsl). In this report we demonstrate that female expression of Slp results from homozygous recessive allele(s) at a single autosomal locus that maps to a 2.2-centimorgan interval on chromosome 13. This conclusion was supported by extensive genetic analyses including the use of polymorphic microsatellites to type numerous backcross progeny and a recombinant inbred series and to identify the congenic interval in three independently derived congenic strains. Four attractive candidate genes were identified by the localization of rsl. Interestingly, rsl was found not only to enable expression in females but to also increase expression in males. The findings suggest that the expression of Slp and perhaps other sexually dimorphic proteins is regulated by two pathways, one that is dependent upon rsl but not androgens and another that is rsl-independent but requires androgens.

An investigation of the adequacy of MEDLINE searches for randomized controlled trials (RCTs) of the effects of mental health care

Valid reviews of the effects of mental health care depend on identifying as high a proportion as possible of relevant randomized controlled trials (RCTs). To investigate the sensitivity and precision both of MEDLINE and of hand-searching for RCTs in mental health, 12 journals specializing in mental health and indexed by the National Library of Medicine (NLM) for MEDLINE were searched for the years 1971, 1976, 1981, 1986 and 1991. The sensitivity of the hand-search was 94% (95% Confidence Interval (CI) 93-95%), but it had a precision of only 7% (CI 6-8%). The optimal MEDLINE search had a sensitivity of only 52% (CI 48-56%) and a precision of 59% (CI 55-63%). Of the reports of RCTs identified by the hand-search, 9% (CI 7-11%) were not included in MEDLINE at all. Authors had included methodological descriptions in 84% (CI 80-88%) of RCTs found by the hand-search but missed by the MEDLINE search. Systematic reviews of mental health care which are based solely on MEDLINE searches of the literature will miss a large proportion of the relevant RCTs, and are thus liable to random error and bias. A register of mental health RCTs is urgently required.

Nitric oxide production in islets from nonobese diabetic mice: aminoguanidine-sensitive and -resistant stages in the immunological diabetic process

The role of nitric oxide (NO.) in the development of immunologically induced diabetes was examined. Transfer of spleen cells obtained from diabetic female nonobese diabetic (NOD) mice to nondiabetic irradiated males induced diabetes 11-13 days after transfer. Islets isolated from recipient male mice produced NO. in a time-dependent fashion. The production of nitrite was initially detected at day 6 after transfer, with increasing levels by days 9 and 13. Under similar conditions glucose-induced insulin secretion by isolated NOD mouse islets was irreversibly reduced by approximately 40% at days 6, 9, and 13 after transfer of spleen cells. The number of islets harvested per pancreas by the 9th and 13th day after transfer was decreased by 20-25% as compared to controls. Treatment of male NOD mice with aminoguanidine, an inhibitor of the inducible form of NO. synthase, reduced the production of NO. in islets and delayed the development of diabetes by 3-8 days. The temporary inhibition by aminoguanidine was dependent on both inhibitor concentration and number of spleen cells transferred. These results indicate that NO. is produced in NOD islets as a result of an immunological diabetogenic process and suggests a role of this compound in the immunological diabetic process.