An epidemic of chronic kidney disease of unknown origin has emerged in the last decade in Central America and has been named Mesoamerican nephropathy. This form of chronic kidney disease is present ...primarily in young male agricultural workers from communities along the Pacific coast, especially workers in the sugarcane fields. In general, these men have a history of manual labor under very hot conditions in agricultural fields. Clinically, they usually present with normal or mildly elevated systemic blood pressure, asymptomatic yet progressive reduction in estimated glomerular filtration rate, low-grade non-nephrotic proteinuria, and often hyperuricemia and or hypokalemia. Diabetes is absent in this population. Kidney biopsies that have been performed show a chronic tubulointerstitial disease with associated secondary glomerulosclerosis and some signs of glomerular ischemia. The cause of the disease is unknown; this article discusses and analyzes some of the etiologic possibilities currently under consideration. It is relevant to highlight that recurrent dehydration is suggested in multiple studies, a condition that possibly could be exacerbated in some cases by other conditions, including the use of nonsteroidal anti-inflammatory agents. At present, Mesoamerican nephropathy is a medical enigma yet to be solved.
Since the first description of the association between chronic kidney disease and heart disease, many epidemiological studies have confirmed and extended this finding. As chronic kidney disease ...progresses, kidney-specific risk factors for cardiovascular events and disease come into play. As a result, the risk for cardiovascular disease is notably increased in individuals with chronic kidney disease. When adjusted for traditional cardiovascular risk factors, impaired kidney function and raised concentrations of albumin in urine increase the risk of cardiovascular disease by two to four times. Yet, cardiovascular disease is frequently underdiagnosed and undertreated in patients with chronic kidney disease. This group of patients should, therefore, be acknowledged as having high cardiovascular risk that needs particular medical attention at an individual level. This view should be incorporated in the development of guidelines and when defining research priorities. Here, we discuss the epidemiology and pathophysiological mechanisms of cardiovascular risk in patients with chronic kidney disease, and discuss methods of prevention.
Aims
Individuals with diabetes and chronic kidney disease (CKD) are at high risk for renal events. Recent trials of novel treatments have been negative, possibly because of variability in response to ...treatment of the target risk factor. Atrasentan is a selective endothelin A receptor antagonist that reduces urinary albumin‐to‐creatinine ratio (UACR), with a large variability between patients. We are assessing its effect on renal outcomes in the Study Of diabetic Nephropathy with AtRasentan (SONAR; NCT01858532) with an enrichment design (>30% lowering of albuminuria) to select patients most likely to benefit.
Materials and Methods
SONAR is a randomized, double‐blind, placebo‐controlled trial with approximately 3500 participants who have stage 2–4 CKD and macroalbuminuria and are receiving a maximum tolerated dose of a renin‐angiotensin system inhibitor.
Results
After 6 weeks of exposure to atrasentan 0.75 mg once daily (enrichment period), participants with ≥30% UACR decrease and no tolerability issues (responders) were randomly assigned to placebo or atrasentan 0.75 mg/day. The responder group will be used for primary efficacy and safety analyses. Approximately 1000 participants with <30% UACR reduction (non‐responders) were also randomized to placebo or atrasentan. The primary endpoint is a composite of a sustained doubling of serum creatinine or end‐stage renal disease. The original power calculation indicated that a total of 425 primary renal events in the responder group provides 90% power to detect a 27% reduction in relative risk (alpha level of .05).
Conclusion
SONAR aims to determine whether atrasentan added to guideline‐recommended therapies safely reduces the risk of CKD progression and delays the onset of end‐stage renal disease in patients with type 2 diabetes and nephropathy. SONAR also aims to establish whether the enrichment of patients based on their initial “surrogate” response to atrasentan will deliver a trial design in accord with personalized treatment of diabetic kidney disease.
Sodium-Glucose Cotransporter 2 inhibitors (SGLT2i), or gliflozins, are a group of antidiabetic drugs that have shown improvement in renal and cardiovascular outcomes in patients with kidney disease, ...with and without diabetes. In this review, we will describe the different proposed mechanisms of action of SGLT2i. Gliflozins inhibit renal glucose reabsorption by blocking the SGLT2 cotransporters in the proximal tubules and causing glucosuria. This reduces glycemia and lowers HbA
by ~1.0%. The accompanying sodium excretion reverts the tubuloglomerular feedback and reduces intraglomerular pressure, which is central to the nephroprotective effects of SGLT2i. The caloric loss reduces weight, increases insulin sensitivity, lipid metabolism, and likely reduces lipotoxicity. Metabolism shifts toward gluconeogenesis and ketogenesis, thought to be protective for the heart and kidneys. Additionally, there is evidence of a reduction in tubular cell glucotoxicity through reduced mitochondrial dysfunction and inflammation. SGLT2i likely reduce kidney hypoxia by reducing tubular energy and oxygen demand. SGLT2i improve blood pressure through a negative sodium and water balance and possibly by inhibiting the sympathetic nervous system. These changes contribute to the improvement of cardiovascular function and are thought to be central in the cardiovascular benefits of SGLT2i. Gliflozins also reduce hepcidin levels, improving erythropoiesis and anemia. Finally, other possible mechanisms include a reduction in inflammatory markers, fibrosis, podocyte injury, and other related mechanisms. SGLT2i have shown significant and highly consistent benefits in renal and cardiovascular protection. The complexity and interconnectedness of the primary and secondary mechanisms of action make them a most interesting and exciting pharmacologic group.
Aim
To assess the risk of major adverse cardiovascular events (MACE) of canagliflozin in Hispanic patients with type 2 diabetes (T2D) and high cardiovascular risk or nephropathy with varying levels ...of kidney function.
Materials and Methods
This post hoc analysis included integrated, pooled data from the CANVAS Program and CREDENCE trial. The effects of canagliflozin versus placebo on major adverse cardiovascular events (MACE; i.e. cardiovascular death, non‐fatal myocardial infarction, and non‐fatal stroke) were assessed in subgroups by baseline estimated glomerular filtration rate (eGFR; <45, 45‐60, and >60 mL/min/1.73 m2) overall and in the Hispanic cohort. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression models, with subgroup by treatment interaction terms added to test for heterogeneity.
Results
A total of 14 543 participants were included; 3029 (20.8%) self‐identified as Hispanic. In the overall population, canagliflozin reduced the risk of MACE compared with placebo (HR, 0.83; 95% CI, 0.75, 0.92), with no heterogeneity observed across eGFR subgroups (interaction P = .22). In the Hispanic cohort, canagliflozin also reduced the risk of MACE (HR, 0.71; 95% CI, 0.55, 0.92), with no heterogeneity by baseline eGFR (interaction P = .25), including among the Hispanic participants at highest risk with a baseline eGFR of less than 45 mL/min/1.73 m2.
Conclusion
Canagliflozin reduced the risk of MACE overall, and among Hispanic participants with T2D and high cardiovascular risk or nephropathy in the CANVAS Program and CREDENCE trial, without heterogeneity by baseline eGFR.
Aim
To assess the effects of dapagliflozin in patients with chronic kidney disease (CKD) and albuminuria, with and without type 2 diabetes, stratified by the Quételet (body mass) index (BMI).
Methods
...We randomized 4304 adult patients with an estimated glomerular filtration rate (eGFR) of 25‐75 ml/min/1.73m2 and urinary albumin‐to‐creatinine ratio of 200‐5000 mg/g to dapagliflozin 10 mg/day or placebo. The primary outcome was a composite of sustained decline in eGFR of 50% or more, kidney failure, or death from kidney or cardiovascular causes. Secondary outcomes included kidney composite endpoint (primary composite endpoint without cardiovascular death), cardiovascular composite endpoint (hospitalized heart failure/ cardiovascular death), and all‐cause mortality. We categorized participants according to World Health Organization BMI criteria: lean/ideal (<25 kg/m2), overweight (25‐< 30 kg/m2), grade 1 obesity (30‐<35 kg/m2), and grade 2/3 obesity (≥35 kg/m2).
Results
Of 4296 (99.8%) randomized participants, 888 (20.7%), 1491 (34.7%), 1136 (26.4%), and 781 (18.2%) were categorized as lean/ideal, overweight, grade 1 obesity, and grade 2/3 obesity, respectively. Median follow‐up was 2.4 years. Benefits of dapagliflozin were observed independent of baseline BMI for primary and secondary endpoints. Hazard ratios (95% CI) for dapagliflozin versus placebo for the primary composite endpoint were 0.60 (0.43, 0.85), 0.55 (0.40, 0.75), 0.71 (0.49, 1.04), and 0.57 (0.37, 0.87) among participants in the lean/ideal, overweight, grade 1 obesity, and grade 2/3 obesity groups (interaction P = .72).
Conclusion
Among participants with CKD and albuminuria, with or without type 2 diabetes, kidney and cardiovascular benefits of dapagliflozin were evident and consistent across the BMI spectrum.
Aims
Renin‐angiotensin system inhibitors (RASi) are the most effective treatments for diabetic kidney disease but significant residual renal risk remains, possibly because of other mechanisms of ...kidney disease progression unrelated to RAS that may be present. Sodium‐glucose co‐transporter‐2 inhibitors reduce albuminuria and may complement RASi by offering additional renal protection. This post hoc analysis investigated the effects of dapagliflozin on cardio‐renal risk factors in patients with type 2 diabetes (T2D) with increased albuminuria treated with or without RASi at baseline.
Materials and methods
We evaluated the effects of dapagliflozin 10 mg/day over 12–24 weeks across 13 placebo‐controlled studies in patients with T2D with a urinary albumin‐to‐creatinine ratio (UACR) ≥30 mg/g at baseline. Patients were divided into two subgroups based on treatment with or without RASi at baseline.
Results
Compared with patients with RASi at baseline (n = 957), patients without RASi (n = 302) were younger, had a shorter duration of diabetes (7 vs. 12 years), higher estimated glomerular filtration rate (eGFR) and lower UACR, serum uric acid (sUA), body weight and systolic blood pressure. Placebo‐adjusted treatment effects of dapagliflozin on UACR, eGFR, glycated haemoglobin and haematocrit over 24 weeks were similar across groups. Mean reductions in body weight and sUA were more distinct in patients without RASi treatment at baseline.
Conclusions
Treatment with dapagliflozin over 24 weeks provides similar clinically relevant improvements in metabolic and haemodynamic parameters, and similar reductions in UACR, in patients with T2D with elevated albuminuria treated with or without RASi at baseline.
In the Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease (DAPA-CKD) randomized, placebo-controlled trial, the sodium-glucose cotransporter 2 inhibitor dapagliflozin ...significantly reduced risk of kidney failure and prolonged survival in patients with CKD with or without type 2 diabetes.
Adults with eGFR of 25-75 ml/min per 1.73 m
and urinary albumin-to-creatinine ratio of 200-5000 mg/g had been randomized to receive dapagliflozin 10 mg/d or placebo. Here, we conducted a prespecified analysis of dapagliflozin's effects in patients with stage 4 CKD (eGFR,30 ml/min per 1.73 m
) at baseline. The primary end point was a composite of time to ≥50% sustained decline in eGFR, ESKD, or kidney or cardiovascular death. Secondary end points were a kidney composite (same as the primary end point but without cardiovascular death), a composite of cardiovascular death or heart failure hospitalization, and all-cause death.
A total of 293 participants with stage 4 CKD received dapagliflozin and 331 received placebo. Patients with stage 4 CKD randomized to dapagliflozin experienced a 27% (95% confidence interval 95% CI: -2 to 47%) reduction in the primary composite endpoint, and 29% (-2 to 51%), 17% (-53 to 55%), and 32% (-21 to 61%) reductions in the kidney, cardiovascular and mortality endpoints, respectively, relative to placebo. Interaction P-values were 0.22, 0.13, 0.63, and 0.95, respectively, comparing CKD stages 4 versus 2/3. The eGFR slope declined by 2.15 and 3.38 ml/min per 1.73 m
per year in the dapagliflozin and placebo groups, respectively (
=0.005). Patients treated with dapagliflozin or placebo had similar rates of serious adverse events and adverse events of interest.
Among patients with stage 4 CKD and albuminuria, the effects of dapagliflozin were consistent with those observed in the DAPA-CKD trial overall, with no evidence of increased risks.
Aim
The SONAR trial uses an enrichment design based on the individual response to the selective endothelin receptor antagonist atrasentan on efficacy (the degree of the individual response in the ...urinary albumin‐to‐creatinine ratio UACR) and safety/tolerability (signs of sodium retention and acute increases in serum creatinine) to assess the effects of this agent on major renal outcomes. The patient population and enrichment results are described here.
Methods
Patients with type 2 diabetes with an estimated glomerular filtration rate (eGFR) within 25 to 75 mL/min/1.73 m2 and UACR between 300 and 5000 mg/g were enrolled. After a run‐in period, eligible patients received 0.75 mg/d of atrasentan for 6 weeks. A total of 2648 responder patients in whom UACR decreased by ≥30% compared to baseline were enrolled, as were 1020 non‐responders with a UACR decrease of <30%. Patients who experienced a weight gain of >3 kg and in whom brain natriuretic peptide exceeded ≥300 pg/mL, or who experienced an increase in serum creatinine >20% (0.5 mg/dL), were not randomized.
Results
Baseline characteristics were similar for atrasentan responders and non‐responders. Upon entry to the study, median UACR was 802 mg/g in responders and 920 mg/g in non‐responders. After 6 weeks of treatment with atrasentan, the UACR change in responders was −48.8% (95% CI, −49.8% to −47.9%) and in non‐responders was −1.2% (95% CI, −6.4% to 3.9%). Changes in other renal risk markers were similar between responders and non‐responders except for a marginally greater reduction in systolic blood pressure and eGFR in responders.
Conclusions
The enrichment period has successfully identified a population with a profound UACR reduction without clinical signs of sodium retention in whom a large atrasentan effect on clinically important renal outcomes is possible. The SONAR trial aims to establish whether atrasentan confers renal protection.
Aim
To evaluate whether atrasentan plasma exposure explains between‐patient variability in urinary albumin‐to‐creatinine ratio (UACR) response, a surrogate for kidney protection, and B‐type ...natriuretic peptide (BNP) response, a surrogate for fluid expansion.
Methods
Type 2 diabetic patients with chronic kidney disease (n = 4775) received 0.75 mg atrasentan for 6 weeks in the active run‐in period. Individual area under the concentration‐time‐curve (AUC) was estimated using a population pharmacokinetic model. The association between atrasentan AUC, other clinical characteristics, and UACR and BNP response, was estimated using linear regression.
Results
The median atrasentan AUC was 43.8 ng.h/mL with a large variation among patients (2.5th‐97.5th percentiles P: 12.6 to 197.5 ng.h/mL). Median UACR change at the end of enrichment was −36.0% and median BNP change was 8.7%, which also varied among patients (UACR, 2.5th‐97.5th P: −76.2% to 44.5%; BNP, 2.5th‐97.5th P: −71.5% to 300.0%). In the multivariable analysis, higher atrasentan AUC was associated with greater UACR reduction (4.88% per doubling in ng.h/mL 95% confidence interval {CI}: 6.21% to 3.52%, P < .01) and greater BNP increase (3.08% per doubling in ng.h/mL 95% CI: 1.12% to 4.11%, P < .01) independent of estimated glomerular filtration rate, haemoglobin or BNP. Caucasian patients compared with black patients had greater UACR reduction (7.06% 95% CI: 1.38% to 13.07%) and also greater BNP increase (8.75% 95% CI: 1.65% to 15.35%). UACR response was not associated with BNP response (r = 0.06).
Conclusion
Atrasentan plasma exposure varied among individual patients and partially explained between‐patient variability in efficacy and safety response.
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