Treatments for Chronic Kidney Disease: A Systematic Literature Review of Randomized Controlled Trials

A kidney-specific fasting-mimicking diet induces podocyte reprogramming and restores renal function in glomerulopathy

Cycles of a fasting-mimicking diet (FMD) promote regeneration and reduce damage in the pancreases, blood, guts, and nervous systems of mice, but their effect on kidney disease is unknown. In addition, a FMD has not been tested in rats. Here, we show that cycles of a newly developed low-salt FMD (LS-FMD) restored normal proteinuria and nephron structure and function in rats with puromycin-induced nephrosis compared with that in animals with renal damage that did not receive the dietary intervention. LS-FMD induced modulation of a nephrogenic gene program, resembling renal developmental processes in multiple kidney structures. LS-FMD also activated podocyte-lineage reprogramming pathways and promoted a quiescent state in mature podocytes in the rat kidney damage model. In a pilot clinical study in patients with chronic kidney disease, FMD cycles of 5 days each month for 3 months promoted renoprotection, including reduction of proteinuria and improved endothelial function, compared with that in patients who did not receive the FMD cycles. These results show that FMD cycles, which promote the reprogramming of multiple renal cell types and lead to glomerular damage reversal in rats, should be tested further for the treatment of progressive kidney diseases.

Global forecasting of chronic kidney disease mortality rates and numbers with the generalized additive model

BACKGROUND

Chronic kidney disease (CKD) is an important public health problem worldwide; therefore, forecasting CKD mortality rates and death numbers globally is vital for planning CKD prevention programs. This study aimed to characterize the temporal trends in CKD mortality at the international level from 1990 to 2019 and predict CKD mortality rates and numbers until 2030.

METHODS

Data were obtained from the Global Burden of Disease 2019 Study. A joinpoint regression model was used to estimate the average annual percentage change in CKD mortality rates and numbers. Finally, we used a generalized additive model to predict CKD mortality through 2030.

RESULTS

The number of CKD-related deaths worldwide increased from 591.80 thousand in 1990 to 1425.67 thousand in 2019. The CKD age-adjusted mortality rate increased from 15.95 per 100,000 people to 18.35 per 100,000 people during the same period. Between 2020 and 2030, the number of CKD deaths is forecasted to increase further to 1812.85 thousand by 2030. The CKD age-adjusted mortality rate is expected to decrease slightly to 17.76 per 100,000 people (95% credible interval (CrI): 13.84 to 21.68). Globally, it is predicted that in the next decade, the CKD mortality rate will decrease in men, women, all subgroups of disease etiology except glomerulonephritis, people younger than 40 years old, and all groupings of countries based on the sociodemographic index (SDI) except high-middle-SDI countries.

CONCLUSIONS

The CKD mortality rate is predicted to decrease in the next decade. However, more attention should be given to people with glomerulonephritis, people over 40 years old, and people in high- to middle-income countries because the mortality rate due to CKD in these subgroups is expected to increase until 2030.

Clinical Outcomes in Patients with CKD and Rapid or Non-rapid eGFR Decline: A Report from the DISCOVER CKD Retrospective Cohort

INTRODUCTION

This analysis examined the baseline characteristics and clinical outcomes of patients with chronic kidney disease (CKD) and rapid or non-rapid estimated glomerular filtration rate (eGFR) decline, using retrospective data from DISCOVER CKD (ClinicalTrials.gov, NCT04034992).

METHODS

Data (2008-2020) were extracted from UK Clinical Practice Research Datalink, US TriNetX, US Limited Claims and Electronic Health Record Dataset, and Japan Medical Data Vision. Patients with CKD (two consecutive eGFR measures < 75 mL/min/1.73 m2 recorded 90-730 days apart) were included. Rapid eGFR decline was defined as an annual decline of > 4 mL/min/1.73 m2 at 2 years post-index; non-rapid eGFR decline was defined as an annual decline of ≤ 4 mL/min/1.73 m2. Clinical outcomes assessed included all-cause mortality, kidney outcomes (composite risk of kidney failure [progression to CKD stage 5] or > 50% eGFR decline, and kidney failure alone), cardiovascular events-including major adverse cardiovascular events (MACE; non-fatal myocardial infarction/stroke and cardiovascular death)-and all-cause hospitalization.

RESULTS

Across databases, rapid eGFR decline occurred in 13.7% of 804,237 eligible patients. Mean annual eGFR decline ranged between - 6.21 and - 6.86 mL/min/1.73 m2 in patients with rapid eGFR decline versus between - 0.11 and - 0.77 mL/min/1.73 m2 in patients with non-rapid eGFR decline. Rapid eGFR decline was associated with increased comorbidity burden and medication prescriptions. Across databases, the composite risk of kidney failure or > 50% decline in eGFR was significantly greater in patients with rapid versus non-rapid eGFR decline (P < 0.01); all-cause mortality, kidney failure alone, MACE, and all-cause hospitalization each significantly increased in two databases (P < 0.01-0.05).

CONCLUSION

Understanding patient factors associated with rapid eGFR decline in patients with CKD may help identify individuals who would benefit from proactive management to minimize the risk of adverse outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04034992.

Hyperkalemia Burden and Treatment Pathways in Patients with CKD: Findings From the DISCOVER CKD Retrospective Cohort

Key Points

Hyperkalemia (HK) is associated with increased comorbidity burden in patients with CKD. Reducing serum potassium levels after HK episodes helps continuation of renin-angiotensin-aldosterone system inhibitor treatment. In Japan, HK treatment pathways are more heterogeneous and potassium binders are more commonly prescribed compared with the United Kingdom.

Background

This analysis used retrospective data from the DISCOVER CKD observational study (NCT04034992 ) to describe the burden of and treatment pathways for hyperkalemia (HK) in patients with CKD.

Methods

Data were extracted from the following databases: UK Clinical Practice Research Datalink (2008–2019) and Japan Medical Data Vision (2008–2017). Patients with CKD (two eGFR measures <75 ml/min per 1.73 m2 recorded ≥90 days apart) and HK (at least two serum potassium [sK+] measures >5.0 mmol/L) were compared with patients without HK (sK+ <5.0 mmol/L); HK index event was the second sK+ measurement. Outcomes included baseline characteristics and treatment pathways for key medications (renin-angiotensin-aldosterone system inhibitors [RAASi], diuretics and potassium [K+] binders).

Results

In the UK Clinical Practice Research Datalink, 37,713 patients with HK and 142,703 patients without HK were included for analysis (HK prevalence 20.9%). In the Japan Medical Data Vision, 5924 patients with HK and 74,272 patients without HK were included for analysis (HK prevalence 7.4%). In both databases, median eGFR was lower and comorbidities such as hypertension, heart failure, type 2 diabetes, and AKI were more prevalent among patients with versus without HK, and most patients were taking RAASi at the time of HK index. Treatment pathways were more heterogeneous in Japan; <0.2% of patients with CKD and HK in the United Kingdom initiated K+ binders within 3 months of HK index versus 18.7% in Japan. The proportions of patients with CKD and HK who stopped treatment with diuretics, K+ binders, and RAASi during follow-up were 48.7%, 76.5%, and 50.6%, respectively, in the United Kingdom, and 22.9%, 53.6%, and 29.2%, respectively, in Japan.

Conclusions

HK was associated with increased comorbidity burden in patients with CKD. Variations in treatment pathways between the United Kingdom and Japan reflect the previous lack of a standardized approach to HK management in CKD.

Effect of Avenciguat on Albuminuria in Patients with CKD: Two Randomized Placebo-Controlled Trials

Key Points

Background

Avenciguat is a novel, potent soluble guanylate cyclase activator in development for CKD. Two trials investigated avenciguat in diabetic (NCT04750577) and non-diabetic (NCT04736628) CKD.

Methods

A prespecified pooled analysis of two randomized, double-blind, placebo-controlled trials of identical design. Adults with CKD (eGFR ≥20 and <90 ml/min per 1.73 m2, urine albumin–creatinine ratio [UACR] ≥200 and <3500 mg/g) were randomized to 20 weeks of placebo or avenciguat 1, 2, or 3 mg three times daily (TID), adjunctive to angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. The primary end point was change from baseline in UACR in 10-hour urine at week 20, analyzed per protocol. The secondary end point was UACR change from baseline in first morning void urine at week 20. Safety was monitored throughout.

Results

Overall, 500 patients (mean age 62 years [SD 13]; mean eGFR 44 ml/min per 1.73 m2 [SD 18] and median 10-hour UACR 719 [interquartile range, 379–1285] mg/g) received placebo (n=122) or avenciguat 1 mg (n=125), 2 mg (n=126), or 3 mg (n=127) TID. All 243 patients in study one and 27 of 261 patients in study two had diabetes mellitus. Avenciguat 1, 2, and 3 mg TID reduced UACR in 10-hour and first morning void urine versus placebo throughout the treatment period. At week 20, placebo-corrected geometric mean changes (95% confidence interval) from baseline in UACR in 10-hour urine with avenciguat 1, 2, and 3 mg TID were −15.5% (−26.4 to −3.0), −13.2% (−24.6 to −0.1), and −21.5% (−31.7 to −9.8), respectively, analyzed per protocol. Corresponding changes in first morning void urine were −19.4% (−30.0 to −7.3), −15.5% (−26.9 to −2.5), and −23.4% (−33.5 to −11.8), respectively. Avenciguat was well tolerated; the overall frequency of adverse events was low and similar to placebo. The number of patients who discontinued the study drug because of adverse events with avenciguat 1, 2, and 3 mg TID were five (4%), 11 (9%), and 11 (9%), respectively, compared with four (3%) in the placebo group.

Conclusions

Avenciguat lowered albuminuria and was well tolerated in patients with CKD.

Clinical Trial registry name and registration number:

A Study to Test the Effect of Different Doses of BI 685509 on Kidney Function in People With Diabetic Kidney Disease, NCT04750577, and A Study to Test the Effect of Different Doses of Avenciguat (BI 685509) on Kidney Function in People With Chronic Kidney Disease, NCT04736628.

Podcast

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_06_27_ASN0000000000000418.mp3

Current perspective on circadian function of the kidney

Behavior and function of living systems are synchronized by the 24-h rotation of the Earth that guides physiology according to time of day. However, when behavior becomes misaligned from the light-dark cycle, such as in rotating shift work, jet lag, and even unusual eating patterns, adverse health consequences such as cardiovascular or cardiometabolic disease can arise. The discovery of cell-autonomous molecular clocks expanded interest in regulatory systems that control circadian physiology including within the kidney, where function varies along a 24-h cycle. Our understanding of the mechanisms for circadian control of physiology is in the early stages, and so the present review provides an overview of what is known and the many gaps in our current understanding. We include a particular focus on the impact of eating behaviors, especially meal timing. A better understanding of the mechanisms guiding circadian function of the kidney is expected to reveal new insights into causes and consequences of a wide range of disorders involving the kidney, including hypertension, obesity, and chronic kidney disease.

Glucose-lowering treatment pathways of individuals with chronic kidney disease and type 2 diabetes according to the Kidney Disease: Improving Global Outcomes 2012 risk classification

AIMS

To describe treatment pathways for key glucose-lowering therapies in individuals with chronic kidney disease (CKD) and type 2 diabetes (T2D) using retrospective data from DISCOVER CKD (NCT04034992).

METHODS

Data were extracted from the UK Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics data (2008-2020) and the US integrated Limited Claims and Electronic Health Records Database (LCED; 2012-2019). Eligible individuals were aged ≥18 years with CKD, identified by two consecutive estimated glomerular filtration rate (eGFR) measures (15-<75 mL/min/1.73 m2 ; 90-730 days apart; index date was the second measurement) and T2D. Chronological treatment pathways for glucose-lowering therapies prescribed on or after CKD index to end of follow-up were computed. Median time and proportion of overall follow-up time on treatment were described for each therapy by database and by eGFR and urinary albumin-to-creatinine ratio (UACR) categories.

RESULTS

Of 36,951 and 4339 eligible individuals in the CPRD and LCED, respectively, median baseline eGFR was 67.8 and 64.9 mL/min/1.73 m2 ; 64.2 and 63.9% received metformin prior to index; and median (interquartile range) time on metformin during follow-up was 917 (390-1671) and 454 (192-850) days (accounting for ~75% of follow-up time in both databases). The frequency of combination treatment increased over time. There were trends towards decreased metformin prescriptions with decreasing eGFR and increasing UACR within each eGFR category.

CONCLUSIONS

Individuals with CKD and T2D had many combinations of therapies and substantial follow-up time on therapy. These results highlight opportunities for improved CKD management.

GLUT9 as a potential drug target for chronic kidney disease: Drug target validation by a Mendelian randomization study

Although chronic kidney disease (CKD) is recognized as a major public health concern, effective treatment strategies have yet to be developed. Identification and validation of drug targets are key issues in the development of therapeutic agents for CKD. Uric acid (UA), a major risk factor for gout, has also been suggested to be a risk factor for CKD, but the efficacy of existing urate-lowering therapies for CKD is controversial. We focused on five uric acid transporters (ABCG2, SLC17A1, SLC22A11, SLC22A12, SLC2A9) as potential drug targets and evaluated the causal association between serum UA levels and estimated glomerular filtration rate (eGFR) using single-SNP Mendelian Randomization. The results showed a causal association between genetically predicted changes in serum UA levels and eGFR when genetic variants were selected from the SLC2A9 locus. Estimation based on a loss-of-function mutation (rs16890979) showed that the changes in eGFR per unit increase in serum UA level was -0.0082 ml/min/1.73 m2 (95% CI -0.014 to -0.0025, P = 0.0051). These results indicate that SLC2A9 may be a novel drug target for CKD that preserves renal function through its urate-lowering effect.

The Role of Expert Opinion in Projecting Long-Term Survival Outcomes Beyond the Horizon of a Clinical Trial

INTRODUCTION

Clinical trials often have short follow-ups, and long-term outcomes such as survival must be extrapolated. Current extrapolation methods often produce a wide range of survival values. To minimize uncertainty in projections, we developed a novel method that incorporates formally elicited expert opinion in a Bayesian analysis and used it to extrapolate survival in the placebo arm of DAPA-CKD, a phase 3 trial of dapagliflozin in patients with chronic kidney disease (NCT03036150).

METHODS

A summary of mortality data from 13 studies that included DAPA-CKD-like populations and training on elicitation were provided to six experts. An elicitation survey was used to gather the experts' 10- and 20-year survival estimates for patients in the placebo arm of DAPA-CKD. These estimates were combined with DAPA-CKD mortality and general population mortality (GPM) data in a Bayesian analysis to extrapolate long-term survival using seven parametric distributions. Results were compared with those from standard frequentist approaches (with and without GPM data) that do not incorporate expert opinion.

RESULTS

The group expert-elicited estimate for 20-year survival was 31% (lower estimate, 10%; upper estimate, 40%). In the Bayesian analysis, the 20-year extrapolated survival across the seven distributions was 14.9-39.1%, a range that was 2.4- and 1.6-fold smaller than those produced by the frequentist methods (0.0-56.9% without and 0.0-39.2% with GPM data).

CONCLUSIONS

Using expert opinion in a Bayesian analysis provided a robust method for extrapolating long-term survival in the placebo arm of DAPA-CKD. The method could be applied to other populations with limited survival data.

[Classical nephroprotection: Renin angiotensin aldosterone system inhibitors]

The role of the renin angiotensin aldosterone system (RAAS) in the pathophysiology of hypertension, cardiovascular disease and kidney disease has been known for years. RAAS inhibitors have been the mainstay of chronic kidney disease (CKD) treatment. Studies have shown that therapy with angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensinII receptor blockers (ARBs) reduce the excretion of albuminuria and slow the progression of kidney disease in patients with and without diabetes. In clinical practice, RAAS inhibitors are recommended as the antihypertensive of choice in patients with CKD and albuminuria with or without diabetes. In addition, they have demonstrated cardiovascular benefits beyond blood pressure control. The use of RAAS inhibitors in non-proteinuric nephropathy and advanced CKD is not without controversy. Double blockade of the RAAS is contraindicated. On the other hand, it is essential to know how to titrate doses and avoid side effects, mainly hyperkalaemia.

Costs Associated With Progression of Mildly Reduced Kidney Function Among Medicare Advantage Enrollees

Rationale & Objective

The prevalence of early chronic kidney disease (CKD) in older adults has increased in the past 2 decades, yet CKD disease progression, overall, is variable. It is unclear whether health care costs differ by progression trajectory. The purpose of this study was to estimate the trajectories of CKD progression and examine Medicare Advantage (MA) health care costs of each trajectory over a 3-year period in a large cohort of MA enrollees with mildly reduced kidney function.

Study Design

Cohort study.

Setting & Population

421,187 MA enrollees with stage G2 CKD in 2014-2017.

Outcomes

We identified 5 trajectories of kidney function over time.

Model Perspective & Timeframe

Mean total health care costs for each of the trajectories were described in each of the following 3 years from a payer perspective: 1 year before and 2 years after the index date establishing stage G2 CKD (study entry).

Results

The mean estimated glomerular filtration rate (eGFR) at study entry was 75.9 mL/min/1.73 m2 and the median (interquartile range) follow-up period was 2.6 (1.6, 3.7) years. The cohort had a mean age of 72.6 years and had predominantly female participants (57.2%), and White (71.2%). We identified the following 5 distinct trajectories of kidney function: a stable eGFR (22.3%); slow eGFR decline with a mean eGFR at study entry of 78.6 (30.2%); slow eGFR decline with an eGFR at study entry of 70.9 (28.4%); steep eGFR decline (16.3%); and accelerated eGFR decline (2.8%). Mean costs of enrollees with accelerated eGFR decline were double the MA enrollees' mean costs in each of the other 4 trajectories in every year ($27,738 vs $13,498 for a stable eGFR 1 year after study entry).

Limitations

Results may not generalized beyond MA and a lack of albumin values.

Conclusions

The small fraction of MA enrollees with accelerated eGFR decline has disproportionately higher costs than other enrollees with mildly reduced kidney function.

Genetic loci and prioritization of genes for kidney function decline derived from a meta-analysis of 62 longitudinal genome-wide association studies

Estimated glomerular filtration rate (eGFR) reflects kidney function. Progressive eGFR-decline can lead to kidney failure, necessitating dialysis or transplantation. Hundreds of loci from genome-wide association studies (GWAS) for eGFR help explain population cross section variability. Since the contribution of these or other loci to eGFR-decline remains largely unknown, we derived GWAS for annual eGFR-decline and meta-analyzed 62 longitudinal studies with eGFR assessed twice over time in all 343,339 individuals and in high-risk groups. We also explored different covariate adjustment. Twelve genome-wide significant independent variants for eGFR-decline unadjusted or adjusted for eGFR-baseline (11 novel, one known for this phenotype), including nine variants robustly associated across models were identified. All loci for eGFR-decline were known for cross-sectional eGFR and thus distinguished a subgroup of eGFR loci. Seven of the nine variants showed variant-by-age interaction on eGFR cross section (further about 350,000 individuals), which linked genetic associations for eGFR-decline with age-dependency of genetic cross-section associations. Clinically important were two to four-fold greater genetic effects on eGFR-decline in high-risk subgroups. Five variants associated also with chronic kidney disease progression mapped to genes with functional in-silico evidence (UMOD, SPATA7, GALNTL5, TPPP). An unfavorable versus favorable nine-variant genetic profile showed increased risk odds ratios of 1.35 for kidney failure (95% confidence intervals 1.03-1.77) and 1.27 for acute kidney injury (95% confidence intervals 1.08-1.50) in over 2000 cases each, with matched controls). Thus, we provide a large data resource, genetic loci, and prioritized genes for kidney function decline, which help inform drug development pipelines revealing important insights into the age-dependency of kidney function genetics.

Low Adherence to Kidney Disease: Improving Global Outcomes 2012 CKD Clinical Practice Guidelines Despite Clear Evidence of Utility

Introduction

Kidney Disease: Improving Global Outcomes (KDIGO) 2012 guidelines classify chronic kidney disease (CKD) risk or prognosis using estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR). We assessed patient characteristics and outcomes according to the KDIGO classification, using data from DISCOVER CKD (NCT04034992).

Methods

Data were extracted from the US integrated Limited Claims and Electronic Health Record Dataset and TriNetX databases, and the UK Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office for National Statistics databases. Eligible patients were aged ≥18 years with CKD, and identified by 2 consecutive eGFR measures (5 to <75 ml/min/1.73 m2; ≥90 days apart [maximum 730]) from January 2008. Index date was the second eGFR measurement; patients were categorized using the UACR measure closest to the index. Outcomes included patient characteristics, eGFR or UACR measurement frequency, and clinical outcomes per baseline KDIGO classification.

Results

Across databases, only 8.6% of patients with 2 eGFR measures had ≥1 UACR measures. Among 123,807 eligible patients, prevalence of heart failure, hypertension, and type 2 diabetes increased with increasing albuminuria. Incidence rates of mortality and adverse cardiovascular and renal outcomes increased with declining baseline eGFR, and particularly with increasing albuminuria. Median number of eGFR and UACR tests per year post-index ranged from 1.6 to 2.5 and 0.5 to 0.6, respectively, across databases; there was no clear increase in UACR testing frequency following the KDIGO 2012 guidelines.

Conclusion

Albuminuria monitoring is critical for optimal risk stratification in CKD, and our findings highlight an imperative for more regular UACR testing in clinical practice.

Modeling Chronic Kidney Disease in Type 2 Diabetes Mellitus: A Systematic Literature Review of Models, Data Sources, and Derivation Cohorts

INTRODUCTION

As novel therapies for chronic kidney disease (CKD) in type 2 diabetes mellitus (T2DM) become available, their long-term benefits should be evaluated using CKD progression models. Existing models offer different modeling approaches that could be reused, but it may be challenging for modelers to assess commonalities and differences between the many available models. Additionally, the data and underlying population characteristics informing model parameters may not always be evident. Therefore, this study reviewed and summarized existing modeling approaches and data sources for CKD in T2DM, as a reference for future model development.

METHODS

This systematic literature review included computer simulation models of CKD in T2DM populations. Searches were implemented in PubMed (including MEDLINE), Embase, and the Cochrane Library, up to October 2021. Models were classified as cohort state-transition models (cSTM) or individual patient simulation (IPS) models. Information was extracted on modeled kidney disease states, risk equations for CKD, data sources, and baseline characteristics of derivation cohorts in primary data sources.

RESULTS

The review identified 49 models (21 IPS, 28 cSTM). A five-state structure was standard among state-transition models, comprising one kidney disease-free state, three kidney disease states [frequently including albuminuria and end-stage kidney disease (ESKD)], and one death state. Five models captured CKD regression and three included cardiovascular disease (CVD). Risk equations most commonly predicted albuminuria and ESKD incidence, while the most predicted CKD sequelae were mortality and CVD. Most data sources were well-established registries, cohort studies, and clinical trials often initiated decades ago in predominantly White populations in high-income countries. Some recent models were developed from country-specific data, particularly for Asian countries, or from clinical outcomes trials.

CONCLUSION

Modeling CKD in T2DM is an active research area, with a trend towards IPS models developed from non-Western data and single data sources, primarily recent outcomes trials of novel renoprotective treatments.