Acute changes in glomerular filtration rate with renin-angiotensin system (RAS) inhibition: clinical implications

Association between Acute Declines in eGFR during Renin-Angiotensin System Inhibition and Risk of Adverse Outcomes

Key Points

Background

Declines in GFR occur commonly when renin-angiotensin system (RAS) inhibitors are started. Our objective was to determine the relation between declines in eGFR during trials of RAS inhibition and kidney outcomes.

Methods

We included participants with CKD (eGFR <60 ml/min per 1.73 m2) from 17 trials of RAS inhibition. The exposure was subacute declines in eGFR expressed as % change between randomization and month 3, and in the subset of trials with data available, we also examined % change in eGFR between randomization and month 1. The primary outcome was kidney failure with replacement therapy. Cox proportional hazards models were used to examine the association between subacute declines in eGFR and risk of kidney failure. We used spline models to identify the threshold of change in eGFR below which RAS inhibition was favorable (conservatively comparing a given decline in eGFR with RAS inhibition to no decline in the comparator).

Results

A total of 11,800 individuals with mean eGFR 43 (SD 11) ml/min per 1.73 m2 and median urine albumin-to-creatinine ratio of 362 mg/g (interquartile range, 50–1367) were included, and 1162 (10%) developed kidney failure. The threshold of decline in eGFR that favored the use of RAS inhibitors for kidney failure was estimated to be up to 13% (95% confidence interval, 8% to 17%) over a 3-month interval and up to 21% (95% confidence interval, 15% to 27%) over a 1-month interval after starting RAS inhibitors.

Conclusions

In patients treated with RAS inhibitors, ≤13% decline in eGFR over a 3-month period or ≤21% decline over a 1-month period was associated with lower risk of kidney failure compared with no decline in those assigned to placebo or other agents.

Acute Declines in Estimated GFR in Blood Pressure Target Trials and Risk of Adverse Outcomes

RATIONALE & OBJECTIVE

Acute decreases in glomerular filtration rate (GFR) occur commonly during intensive blood pressure (BP) lowering. Our objective was to determine the relationship between acute decreases in estimated GFR and patient outcomes.

STUDY DESIGN

Retrospective observational study.

SETTING & PARTICIPANTS

Participants from 4 randomized controlled trials of intensive BP lowering in chronic kidney disease (Modification of Diet in Renal Disease study, African American Study of Kidney Disease and Hypertension, Systolic Blood Pressure Intervention Trial, and Action to Control Cardiovascular Risk in Diabetes trial).

EXPOSURE

A 4-category exposure defined by the level of acute decrease in estimated GFR (defined as>15% vs≤15% between baseline and month 4) and the randomization to intensive versus usual BP control.

OUTCOMES

Risk of kidney replacement therapy (primary outcome), defined as the need for dialysis or transplant except in the Action to Control Cardiovascular Risk in Diabetes trial, which defined its kidney outcome as a composite occurrence of serum creatinine concentration>3.3mg/dL, kidney failure, or kidney replacement therapy.

ANALYTICAL APPROACH

Multivariable Cox models.

RESULTS

We included 4,473 individuals randomly assigned to intensive versus usual BP control who had a total of 351 kidney outcomes and 304 deaths during median follow-up durations of 22 and 24 months, respectively. Approximately 14% of participants exhibited an acute decrease in eGFR, 11.0% in the usual BP treatment arm and 17.8% in the intensive BP treatment arm. In adjusted models, compared with a≤15% eGFR decrease in the usual BP arm, a≤15% eGFR decrease in the intensive BP control arm was associated with lower risk of the kidney outcome (HR, 0.75; 95% CI, 0.57-0.98). In contrast, a>15% decrease in eGFR was associated with a higher risk of the kidney outcome in the usual (HR, 2.47; 95% CI, 1.80-3.38) and intensive BP treatment arms (HR, 1.99; 95% CI, 1.45-2.73) compared with a≤15% decrease in the usual BP arm.

LIMITATIONS

Observational study, residual confounding.

CONCLUSIONS

Decreases in eGFR of>15% in the usual and intensive BP treatment arms were associated with a higher risk of kidney outcomes compared with a≤15% decrease in the usual BP arm and may be a harbinger of adverse outcomes.

Association between early worsening of kidney function and poor outcomes in patients treated with renin angiotensin system inhibitors: A meta-analysis

AIM

As renin angiotensin system inhibitors (RASi) are widely used in the clinic, early worsening of kidney function (EWKF) after RASi therapy deserves attention, as its clinical significance is unknown. The aim was to evaluate the relationship between EWKF and long-term outcomes including all-cause mortality, kidney and cardiovascular events, in all the patients treated with RASi.

METHODS

We searched PubMed, Embase, and the Cochrane databases for controlled trials that compared the outcomes of patients with and without EWKF after RASi treatment. Our primary outcome was all-cause mortality, and secondary outcomes were kidney and cardiovascular events. We pooled data using a random effects model.

RESULTS

A total of ten studies were enrolled, of which eight were randomized trials (including 33 454 patients) and two were observational studies (including 148 144 patients). Of the eight randomized trials, 4996 patients with type 2 diabetes, 19 118 with heart failure (HF), and 9340 with atherosclerotic vascular disease and diabetes with end-organ damage. Both observational studies investigated all kinds of patients with initial RASi treatment. In patients with RASi, the EWKF group had a higher risk of all-cause mortality than the no-EWKF group in the randomized studies (n =  13 581; RR, 1.22; 95% CI, 1.04-1.42; P = .02) and in observational studies (n = 148 144; OR, 1.70; 95% CI, 1.43-2.01; P < .00001). In patients who experienced EWKF, no statistically significant difference was found between the efficacy of RASi and placebo in all-cause mortality (n = 1762; RR, 0.85; 95% CI, 0.68-1.06; P = .14).

CONCLUSION

RASi treatment led to an increased incidence of EWKF which was associated with poorer long-term outcomes. As the benefit of RAS blockade to patients with EWKF was limited, we suggest clinicians use RASi with caution when EWKF occurs.

Diabetic kidney disease: new clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "The natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

Aims

This joint document of the Italian Diabetes Society and the Italian Society of Nephrology reviews the natural history of diabetic kidney disease (DKD) in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents.

Data Synthesis

Recent epidemiological studies have disclosed a wide heterogeneity of DKD. In addition to the classical albuminuric phenotype, two new albuminuria-independent phenotypes have emerged, i.e., “nonalbuminuric renal impairment” and “progressive renal decline”, suggesting that DKD progression toward end-stage kidney disease (ESKD) may occur through two distinct pathways, albuminuric and nonalbuminuric. Several biomarkers have been associated with decline of estimated glomerular filtration rate (eGFR) independent of albuminuria and other clinical variables, thus possibly improving ESKD prediction. However, the pathogenesis and anatomical correlates of these phenotypes are still unclear. Also the management of hyperglycemia in patients with type 2 diabetes and impaired renal function has profoundly changed during the last two decades. New anti-hyperglycemic drugs, which do not cause hypoglycemia and weight gain and, in some cases, seem to provide cardiorenal protection, have become available for treatment of these individuals. In addition, the lowest eGFR safety thresholds for some of the old agents, particularly metformin and insulin secretagogues, have been reconsidered.

Conclusions

The heterogeneity in the clinical presentation and course of DKD has important implications for the diagnosis, prognosis, and possibly treatment of this complication. The therapeutic options for patients with type 2 diabetes and impaired renal function have substantially increased, thus allowing a better management of these individuals.

Clinical features of and risk factors for normoalbuminuric diabetic kidney disease in hospitalized patients with type 2 diabetes mellitus: a retrospective cross-sectional study

BACKGROUND

Normoalbuminuric diabetic kidney disease (NADKD) is a newly defined DKD, the clinical features and pathogenesis for which are still being understood. This study aimed to investigate the features and risk factors for NADKD in patients with type 2 diabetes mellitus (T2DM).

METHODS

A retrospective cross-sectional study was conducted. The related clinical and laboratory data of patients with T2DM hospitalized between August 2012 and January 2020 were collected for statistical analysis. We classified the patients with T2DM into four groups on the basis of the presence or absence of albuminuria and reduced estimated glomerular filtration rate (eGFR). Analysis of variance, the Kruskal-Wallis test, and the chi-square test were used to compare the groups. Binary logistic regression analyses with a forward stepwise method were performed to explore the risk factors for renal dysfunction in hospitalized patients with normoalbuminuric T2DM.

RESULTS

Among the 1620 patients evaluated, 500 (30.9%) had DKD, of which 9% had NADKD. The prevalence of stroke, cardiovascular events, carotid plaque, and peripheral arterial disease in NADKD was significantly higher than in a non-DKD control group (normoalbuminuric T2DM patients with eGFR of ≥60 ml/min/1.73 m²). Regression analyses revealed that three significant independent factors were associated with NADKD: age (OR = 1.089, confidence interval [CI] 95% [1.055-1.123], p < 0.001), previous use of renin-angiotensin system inhibitors (RASIs; OR = 2.330, CI 95% [1.212-4.481], p = 0.011), and glycated hemoglobin (HbA1c; OR = 0.839, CI 95% [0.716-0.983], p = 0.03).

CONCLUSIONS

NADKD is mainly associated with macrovascular rather than microvascular complications. NADKD is more common in patients with normoalbuminuric T2DM with older age, previous use of RASIs, and good glycemic control.

Impact of Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers on Acute Kidney Injury in Emergency Medical Admissions

BACKGROUND

Acute kidney injury (AKI) has been observed in up to 20% of adult hospital admissions. Sepsis, diarrhea and heart failure, all causing reduced effective volume, are considered risk factors for AKI, especially among patients treated with medications that block the Renin-Angiotensin System (RAS), such as angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). We aimed to determine the incidence of acute kidney injury (AKI) in emergency medical admissions in relation to the use and dosage of ACEi/ARB.

METHODS

A single-center observational study conducted in 577 consecutive medical admissions via the Emergency Room (ER) at a University General Hospital in Athens, Greece, between June and July 2018. Patients with incomplete medical records, discharged within 24 h, maintained on chronic renal replacement therapy, admitted to the Cardiology Department or the ICU were excluded. Thus, a total of 309 patients were finally included in this analysis.

RESULTS

We compared 86 (28%) patients who presented in the ER with AKI (AKIGroup) with 223 (72%) patients without AKI (non-AKI Group) at the time of admission. Patients in the AKI Group were more frequently male (58% vs. 46%, p = 0.06), with a higher frequency of diarrhea (16% vs. 6%, p = 0.006), edema (15% vs. 6%, p = 0.014) and lower systolic blood pressure (120 (107-135) vs. 126 (113-140), p = 0.007) at presentation, despite higher prevalence of hypertension (64% vs. 47%, p = 0.006). Overall, ACEi/ARB were more likely to have been prescribed in the AKI Group than in the non-AKI Group (49% vs. 28%, p = 0.001). Interestingly, AKI was more frequently observed in patients treated with the target or above target dosage of ACEi/ARB, but not in those receiving lower than the recommended dosage.

CONCLUSION

The risk of AKI in emergency medical admissions is higher among users of ACEIs/ARB at target or above target dosages. Physicians should adjust RAS blockade according to estimated Glomerular Filtration Rate (eGFR) and advise their patients to withhold ACEi/ARB in cases of acute illness.

The challenge of early glomerular filtration rate decline in response to antihypertensive treatment and chronic kidney disease outcomes

Hypertension and chronic kidney disease (CKD) are closely linked pathological processes. Combating high blood pressure (BP) is an essential part of preventing CKD progression and reducing cardiovascular (CV) risk. Data from recent randomized controlled trials on patients at high CV risk showed the beneficial effects of intensive action to meet BP targets on mortality related to CV disease. The impact of meeting such targets on renal function is still unclear, however, particularly for patients with CKD. This issue has been the object of several post hoc analyses because lowering BP definitely has a nephroprotective role, but the early decline in glomerular filtration rate (GFR) associated with antihypertensive therapies and strict BP targets is still a concern in nephrology clinical practice. The present review discusses the results of studies on this topic, focusing specifically on the clinical significance of early GFR decline in response to treatment with angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, or to different BP targets, in terms of renal and CV outcomes, and how this tips the balance towards continuing or discontinuing antihypertensive therapy.

Diabetic kidney disease: New clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "The natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

AIMS

This joint document of the Italian Diabetes Society and the Italian Society of Nephrology reviews the natural history of diabetic kidney disease (DKD) in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents.

DATA SYNTHESIS

Recent epidemiological studies have disclosed a wide heterogeneity of DKD. In addition to the classical albuminuric phenotype, two new albuminuria-independent phenotypes have emerged, i.e., "nonalbuminuric renal impairment" and "progressive renal decline", suggesting that DKD progression toward end-stage kidney disease (ESKD) may occur through two distinct pathways, albuminuric and nonalbuminuric. Several biomarkers have been associated with decline of estimated glomerular filtration rate (eGFR) independent of albuminuria and other clinical variables, thus possibly improving ESKD prediction. However, the pathogenesis and anatomical correlates of these phenotypes are still unclear. Also the management of hyperglycemia in patients with type 2 diabetes and impaired renal function has profoundly changed during the last two decades. New anti-hyperglycemic drugs, which do not cause hypoglycemia and weight gain and, in some cases, seem to provide cardiorenal protection, have become available for treatment of these individuals. In addition, the lowest eGFR safety thresholds for some of the old agents, particularly metformin and insulin secretagogues, have been reconsidered.

CONCLUSIONS

The heterogeneity in the clinical presentation and course of DKD has important implications for the diagnosis, prognosis, and possibly treatment of this complication. The therapeutic options for patients with type 2 diabetes and impaired renal function have substantially increased, thus allowing a better management of these individuals.

Association of Acute Increases in Plasma Creatinine after Renin-Angiotensin Blockade with Subsequent Outcomes

BACKGROUND AND OBJECTIVES

Data from observational and interventional studies provide discordant results regarding the relationship between creatinine increase after renin-angiotensin system inhibition (RASi) and adverse outcomes. We compared health outcomes among patients with different categories of increase in creatinine upon initiation of RASi in a large population-based cohort.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a retrospective analysis of the Stockholm CREAtinine Measurements database, which contains complete information on diagnoses, medication dispensation claims, and laboratory test results for all Stockholm citizens accessing health care. Included were 31,951 adults initiating RASi during 2007-2011 with available pre- and postinitiation creatinine monitoring. Multivariable Cox regression was used to compare mortality, cardiovascular and ESKD events among individuals with different ranges of creatinine increases within 2 months after starting treatment.

RESULTS

In a median follow-up of 3.5 years, acute increases in creatinine were associated with mortality (3202 events) in a graded manner: compared with creatinine increases <10%, a 10%-19% increase showed an adjusted hazard ratio (HR) of 1.15 (95% confidence interval [95% CI], 1.05 to 1.27); HR 1.22 (95% CI, 1.07 to 1.40) for 20%-29%; HR 1.55 (95% CI, 1.36 to 1.77) for ≥30%. Similar graded associations were present for heart failure (2275 events, P<0.001) and ESKD (52 events; P<0.001), and, less consistently, myocardial infarction (842 events, P=0.25). Results were robust across subgroups, among continuing users, when patients with decreases in creatinine were excluded from the reference group, and after accounting for death as a competing risk.

CONCLUSIONS

Among real-world monitored adults, increases in creatinine (>10%) after initiation of RASi are associated with worse health outcomes. These results do not address the issue of discontinuation of RASi when plasma creatinine increases but do suggest that patients with increases in creatinine have higher subsequent risk of cardiovascular and kidney outcomes.

Association of Changes in Creatinine and Potassium Levels After Initiation of Renin Angiotensin Aldosterone System Inhibitors With Emergency Department Visits, Hospitalizations, and Mortality in Individuals With Chronic Kidney Disease

IMPORTANCE

Renin angiotensin aldosterone system inhibitors (RAASIs) benefit individuals with chronic kidney disease (CKD). Elevations in serum creatinine and potassium levels are common reasons for discontinuation of this therapy, but their incidence and risks are not well characterized in community practice.

OBJECTIVE

To evaluate associations of increased creatinine levels, hyperkalemia, and therapy continuation with the risk of emergency department (ED) visits, hospitalizations, and mortality within 1 year after RAASI therapy initiation in individuals with CKD.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included 4661 individuals with nondialysis CKD newly prescribed a RAASI or a diuretic who were treated at 36 outpatient primary care offices affiliated with Brigham & Women's Hospital and Massachusetts General Hospital, Boston, from January 1, 2009, through December 31, 2011. Individuals receiving a new prescription for a diuretic were used to provide context. All participants had a baseline measure of renal function and at least 1 follow-up measurement of creatinine and potassium levels within 90 days of the prescription. Data were analyzed from January 1, 2009, through December 31, 2012.

EXPOSURES

Changes in creatinine and potassium levels within 90 days after the prescription date and therapy discontinuation.

MAIN OUTCOMES AND MEASURES

Emergency department visits, hospitalizations, and mortality within 1 year.

RESULTS

A total of 4661 individuals were included in the analysis (2506 [53.8%] women; mean [SD] age, 71 [14]; 3931 [84.3%] white; and 4198 [90.1%] with CKD stage 3). Of these, 2354 individuals (50.5%) received RAASIs and 2307 (49.5%) received diuretics. Creatinine level increase of at least 30% after RAASI therapy initiation was found in 158 of 2354 individuals (6.7%); hyperkalemia of greater than 5.0 mEq/L, in 251 of 2354 (10.7%). Increases in creatinine level of at least 30% (unadjusted odds ratio [OR], 1.40; 95% CI, 0.89-2.21), hyperkalemia (unadjusted OR, 1.15; 95% CI, 0.64-2.06), and therapy discontinuation (unadjusted OR, 1.01; 95% CI, 0.71-1.46) were not associated with ED visits or hospitalizations, which was consistent with results from competing risk analyses. Initial increases in creatinine level of at least 30% were associated with mortality in the total cohort (adjusted OR [aOR], 2.17; 95% CI, 1.45-3.25). However, the effect was only independent for diuretics (aOR, 2.27; 95% CI, 1.41-3.66) and not for RAASIs (aOR, 1.82; 95% CI, 0.83-3.99).

CONCLUSIONS AND RELEVANCE

Acute creatinine and potassium level disturbances after initiation of RAASI therapy in individuals with CKD appear to be sustained often often not sustained and not associated with ED visits or hospitalizations, despite therapy continuation. Findings from this study suggest that increases in creatinine level were independently associated with mortality among individuals prescribed diuretics but not RAASIs. Structured laboratory monitoring during RAASI therapy initiation may guide appropriate continuation of therapy in the outpatient setting.

Angiotensin II type 1 receptor blockers decrease kynurenic acid production in rat kidney in vitro

Glutamate (GLU) mainly through N-methyl-D-aspartate (NMDA) receptors plays pivotal role in kidney function regulation. Kynurenic acid (KYNA), a GLU receptors antagonist, is synthesized from kynurenine by kynurenine aminotransferases (KATs). Previously, it was shown that angiotensin II type 1 receptor blockers (ARBs) decrease KYNA production in rat brain in vitro. The aim of this study was to examine the influence of six ARBs: candesartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan on KYNA production on rat kidney in vitro. The effect of ARBs was determined in kidney homogenates and on isolated KAT II enzyme. Among tested ARBs, irbesartan was the most effective KYNA synthesis inhibitor with IC₅₀ of 14.4 μM. Similar effects were observed after losartan (IC₅₀ 45.9 μM) and olmesartan administration (IC₅₀ 108.1 μM), whereas candesartan (IC₅₀ 475.3 μM), valsartan (IC₅₀ 513.9 μM), and telmisartan (IC₅₀ 669.5 μM) displayed lower activity in KYNA synthesis inhibition in rat kidney homogenates in vitro. On the other hand, valsartan (IC₅₀ 27.5 μM) was identified to be the strongest KAT II inhibitor in rat kidney in vitro. Candesartan, losartan, and telmisartan suppressed KAT II activity with IC₅₀ equal to 83.2, 83.3, and 108.3 μM, respectively. Olmesartan and irbesartan were the weakest KAT II inhibitors with IC₅₀ values of 237.4 and 809.9 μM, respectively. Moreover, molecular docking suggested that studied ARBs directly bind to an active site of KAT II. In conclusion, our results indicate that ARBs decrease KYNA synthesis in rat kidney through enzymatic inhibition of KAT II, which may have impact on kidney function.

Acute Declines in Renal Function during Intensive BP Lowering and Long-Term Risk of Death

BACKGROUND

During intensive BP lowering, acute declines in renal function are common, thought to be hemodynamic, and potentially reversible. We previously showed that acute declines in renal function ≥20% during intensive BP lowering were associated with higher risk of ESRD. Here, we determined whether acute declines in renal function during intensive BP lowering were associated with mortality risk among 1660 participants of the African American Study of Kidney Disease and Hypertension and the Modification of Diet in Renal Disease Trial.

METHODS

We used Cox models to examine the association between percentage decline in eGFR (<5%, 5% to <20%, or ≥20%) between randomization and months 3-4 of the trials (period of therapy intensification) and death.

RESULTS

In adjusted analyses, compared with a <5% eGFR decline in the usual BP arm (reference), a 5% to <20% eGFR decline in the intensive BP arm was associated with a survival benefit (hazard ratio [HR], 0.77; 95% confidence interval [95% CI], 0.62 to 0.96), but a 5% to <20% eGFR decline in the usual BP arm was not (HR, 1.01; 95% CI, 0.81 to 1.26; P<0.05 for the interaction between intensive and usual BP arms for mortality risk). A ≥20% eGFR decline was not associated with risk of death in the intensive BP arm (HR, 1.18; 95% CI, 0.86 to 1.62), but it was associated with a higher risk of death in the usual BP arm (HR, 1.40; 95% CI, 1.04 to 1.89) compared with the reference group.

CONCLUSIONS

Intensive BP lowering was associated with a mortality benefit only if declines in eGFR were <20%.