Angiotensin-converting enzyme inhibitors and renal function

Characterization of heart rate variability in end-stage renal disease patients after kidney transplantation with recurrence quantification analysis

Heart rate variability (HRV) is a noninvasive approach to studying the autonomic modulation of heart rate in experimental settings, such as active standing sympathetic stimulation. It is known that patients with end-stage renal disease during active standing have few changes in HRV dynamics, which are improved after hemodialysis. However, it is unknown whether the response to active standing is recovered after definitive treatment with kidney transplantation. This work aims to assess the change in HRV dynamics in the supine position and active standing through time and frequency-based metrics, as well as recurrence plot quantitative analysis (RQA). We studied HRV dynamics by obtaining 5-minute electrocardiographic recordings from kidney transplant recipients who underwent an active standing test. The mean duration of heartbeats and their standard deviation diminished in active standing, compared with the supine position. Also, the low-frequency component of HRV and the presence of diagonal and vertical structures in RQA were predominant. A larger estimated glomerular filtration rate was significantly correlated with broader HRV in the supine position and during active standing. The narrower HRV during active standing may indicate a sympathetic response to external stimuli, which is expected in a functional cardiovascular system, and may be influenced by renal function.

Pharmacovigilance study of the association between dipeptidyl peptidase-4 inhibitors and angioedema using the FDA Adverse Event Reporting System (FAERS)

Dipeptidyl peptidase-4 (DPP-4) plays a minor role in degrading vasoactive peptides that cause angioedema when angiotensin-converting enzyme (ACE) is present and fully functional. This study investigated the association between DPP-4 inhibitors (DPP-4Is) and angioedema, including cases where the concomitant use of ACE inhibitors (ACEIs) was absent. We obtained data from the US Food and Drug Administration Adverse Event Reporting System and performed a disproportionality analysis, using the reporting odds ratio (ROR) and information component (IC) for signal detection in patients aged ≥ 40 years, stratified by age group and sex. No signal was detected for DPP-4Is when the entire dataset was analyzed. However, a signal was detected for the entire female subset group, the three stratified female groups aged ≥ 60 years, and males in their 40 s. After excluding the data of concomitant ACEI users, most ROR and IC values were lower and significant only for females in their 60 s and males aged ≥ 80 years. Regarding individual DPP-4Is signals, those detected for saxagliptin and sitagliptin in some age groups disappeared after excluding the data of ACEI users. Notably, linagliptin was the only DPP-4I where signals were detected in most female groups, regardless of age and without concomitant ACEI use. Our findings suggest that some DPP-4Is were associated with a higher reporting of angioedema as per age and sex, even in the absence of concomitant ACEI use.

Acute Kidney Injury in Children Hospitalized With Diarrheal Illness in the United States

OBJECTIVES

To determine the incidence, correlates, and consequences of acute kidney injury (AKI) among children hospitalized with diarrheal illness in the United States.

METHODS

Using data from Kids' Inpatient Database in 2009 and 2012, we studied children hospitalized with a primary diagnosis of diarrheal illness (weighted N = 113 195). We used the International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis codes 584.5 to 584.9 to capture AKI. We calculated the incidence, correlates, and consequences (mortality, length of stay [LOS], and costs) of AKI associated with hospitalized diarrheal illness using stepwise logistic regression and generalized linear models.

RESULTS

The average incidence of AKI in children hospitalized with diarrheal illness was 0.8%. Hospital location and teaching status were associated with the odds of AKI, as were older age, solid organ transplant, hypertension, chronic kidney disease, and rheumatologic and hematologic conditions. The development of AKI in hospitalized diarrheal illness was associated with an eightfold increase in the odds of in-hospital mortality (odds ratio 8.0; 95% confidence interval [CI] 4.2-15.4). AKI was associated with prolonged LOS (mean increase 3.0 days; 95% CI 2.3-3.8) and higher hospital cost (mean increase $9241; 95% CI $4661-$13 820).

CONCLUSIONS

Several demographic factors and comorbid conditions are associated with the risk of AKI in children hospitalized with diarrheal illness. Although rare, development of AKI in this common pediatric condition is associated with increased mortality, LOS, and hospital cost.

Dipeptidyl peptidase-4 inhibitors can inhibit angiotensin converting enzyme

Angiotensin-1 converting enzyme inhibitors (ACEIs) improve insulin sensitivity. Inhibitors of dipeptidyl peptidase-4 (DPP-4) are anti-diabetic drugs with several cardio-renal effects. Both ACE and DPP-4 share common features. Thus, we tested if they could be inhibited by one inhibitor. First, in silico screening was used to investigate the ability of different DPP-4 inhibitors or ACEIs to interact with DPP-4 and ACE. The results of screening were then extrapolated into animal study. Fifty Sprague Dawley rats were randomly assigned into 5 groups treated with vehicle, captopril, enalapril, linagliptin or sitagliptin. Both low and high doses of each drug were tested. Baseline blood samples and samples at days 1, 8, 10, 14 were used to measure plasma DPP-4 and ACE activities and angiotensin II levels. Active glucagon-like peptide-1 (GLP-1) levels were measured after oral glucose challenge. All tested DPP-4 inhibitors could interact with ACE at a relatively reasonable binding energy while most of the ACEIs only interacted with DPP-4 at a predicted high inhibition constant. In rats, high dose of sitagliptin was able to inhibit ACE activity and reduce angiotensin II levels while linagliptin had only a mild effect. ACEIs did not significantly affect DPP-4 activity or prevent GLP-1 degradation. It seems that some DPP-4 inhibitors could inhibit ACE and this could partially explain the cardio-renal effects of these drugs. Further studies are required to determine if such inhibition could take place in clinical settings.

Hyperfiltration-mediated Injury in the Remaining Kidney of a Transplant Donor

Kidney donors face a small but definite risk of end-stage renal disease 15 to 30 years postdonation. The development of proteinuria, hypertension with gradual decrease in kidney function in the donor after surgical resection of 1 kidney, has been attributed to hyperfiltration. Genetic variations, physiological adaptations, and comorbidities exacerbate the hyperfiltration-induced loss of kidney function in the years after donation. A focus on glomerular hemodynamics and capillary pressure has led to the development of drugs that target the renin-angiotensin-aldosterone system (RAAS), but these agents yield mixed results in transplant recipients and donors. Recent work on glomerular biomechanical forces highlights the differential effects of tensile stress and fluid flow shear stress (FFSS) from hyperfiltration. Capillary wall stretch due to glomerular capillary pressure increases tensile stress on podocyte foot processes that cover the capillary. In parallel, increased flow of the ultrafiltrate due to single-nephron glomerular filtration rate elevates FFSS on the podocyte cell body. Although tensile stress invokes the RAAS, FFSS predominantly activates the cyclooxygenase 2-prostaglandin E2-EP2 receptor axis. Distinguishing these 2 mechanisms is critical, as current therapeutic approaches focus on the RAAS system. A better understanding of the biomechanical forces can lead to novel therapeutic agents to target FFSS through the cyclooxygenase 2-prostaglandin E2-EP2 receptor axis in hyperfiltration-mediated injury. We present an overview of several aspects of the risk to transplant donors and discuss the relevance of FFSS in podocyte injury, loss of glomerular barrier function leading to albuminuria and gradual loss of renal function, and potential therapeutic strategies to mitigate hyperfiltration-mediated injury to the remaining kidney.

Acute Kidney Injury Due to Diarrheal Illness Requiring Hospitalization: Data from the National Inpatient Sample

BACKGROUND

Diarrheal illness is a major reason for hospitalization, but data on consequent acute kidney injury (AKI) are sparse.

OBJECTIVE

To determine the incidence of AKI in infectious and non-infectious diarrheal illness requiring hospitalization and to identify correlates and outcomes of diarrhea-associated AKI.

DESIGN

Using data from the 2012 National Inpatient Sample (NIS), we created a cohort of patients with a primary diagnosis of diarrheal illness. Diarrheal illness, disease correlates, and AKI were defined by ICD-9 diagnosis codes. We used logistic regression with backward variable selection to determine factors independently associated with AKI in infectious and non-infectious diarrheal illness, as well as to determine the association of AKI with in-hospital mortality. We used generalized linear models to assess differences in length of stay and costs of hospitalization.

MAIN MEASURES

The primary outcome was AKI in hospitalized diarrheal illness. Secondary outcomes were in-hospital mortality, length of stay, and cost of hospitalization associated with AKI.

KEY RESULTS

One in ten adults hospitalized with diarrheal illness experienced AKI, with higher incidence rates in older adults. Chronic kidney disease (CKD) and hypertension were associated with increased odds of AKI (all diarrhea OR 4.81, 95% CI 4.52 to 5.12 and OR 1.33, 95% CI 1.27 to 1.40, respectively). AKI in diarrheal illness was associated with substantial increase in mortality (OR 5.05, 95% CI 4.47 to 5.72), length of stay (mean increase 1.7 days [95% CI 1.6 to 1.8]), and cost of hospitalization (mean increase $4411 [95% CI 4023 to 4800]).

CONCLUSION

Acute kidney injury is common and consequential among patients hospitalized for diarrheal illness. Persons with CKD and hypertension are the most susceptible, possibly due to diminished renal reserve and exacerbating effects of treatment with diuretics and renin-angiotensin-aldosterone system blockers. Proactive management of these unique pharmacologic and physiologic factors is necessary to prevent AKI in this vulnerable population.

Estimating One-Year Risk of Incident Chronic Kidney Disease: Retrospective Development and Validation Study Using Electronic Medical Record Data From the State of Maine

Background

Chronic kidney disease (CKD) is a major public health concern in the United States with high prevalence, growing incidence, and serious adverse outcomes.

Objective

We aimed to develop and validate a model to identify patients at risk of receiving a new diagnosis of CKD (incident CKD) during the next 1 year in a general population.

Methods

The study population consisted of patients who had visited any care facility in the Maine Health Information Exchange network any time between January 1, 2013, and December 31, 2015, and had no history of CKD diagnosis. Two retrospective cohorts of electronic medical records (EMRs) were constructed for model derivation (N=1,310,363) and validation (N=1,430,772). The model was derived using a gradient tree-based boost algorithm to assign a score to each individual that measured the probability of receiving a new diagnosis of CKD from January 1, 2014, to December 31, 2014, based on the preceding 1-year clinical profile. A feature selection process was conducted to reduce the dimension of the data from 14,680 EMR features to 146 as predictors in the final model. Relative risk was calculated by the model to gauge the risk ratio of the individual to population mean of receiving a CKD diagnosis in next 1 year. The model was tested on the validation cohort to predict risk of CKD diagnosis in the period from January 1, 2015, to December 31, 2015, using the preceding 1-year clinical profile.

Results

The final model had a c-statistic of 0.871 in the validation cohort. It stratified patients into low-risk (score 0-0.005), intermediate-risk (score 0.005-0.05), and high-risk (score ≥ 0.05) levels. The incidence of CKD in the high-risk patient group was 7.94%, 13.7 times higher than the incidence in the overall cohort (0.58%). Survival analysis showed that patients in the 3 risk categories had significantly different CKD outcomes as a function of time (P<.001), indicating an effective classification of patients by the model.

Conclusions

We developed and validated a model that is able to identify patients at high risk of having CKD in the next 1 year by statistically learning from the EMR-based clinical history in the preceding 1 year. Identification of these patients indicates care opportunities such as monitoring and adopting intervention plans that may benefit the quality of care and outcomes in the long term.

Evaluation of the use of evidence-based angiotensin-converting enzyme inhibitor criteria for the treatment of congestive heart failure: opportunities for pharmacists to improve patient outcomes

BACKGROUND

The under-utilization and under-dosing of angiotensin-converting enzyme inhibitors (ACEIs) in patients with congestive heart failure (CHF) continues to be a problem observed in clinical practice.

OBJECTIVE

To develop and implement drug use evaluation (DUE) criteria for the use of ACEIs in patients with CHF which could be used by pharmacists to ensure that all eligible patients receive an ACEI at an appropriate dose.

METHODS

A retrospective chart review of all patients discharged from the study institution with a diagnosis of CHF during the period of March 1 to July 31, 1998 was conducted using the DUE criteria developed.

RESULTS

Of the 138 patients evaluated, only 68.6% were discharged on ACEI therapy. Additionally, only 40% of those discharged on an ACEI achieved target dose. Multiple regression analysis revealed that males were 2.43 times more likely to be discharged on an ACEI than females, while those on concomitant diuretics or digoxin were less likely to be discharged on an ACEI (25% and 18%, respectively).

CONCLUSIONS

The application of these DUE criteria by pharmacists in hospital and community practice has the potential to improve utilization and dosing of this important class of medications for the management of the symptoms and progression of CHF.

Lithium and angiotensin-converting enzyme inhibitors: evaluation of a potential interaction

The potential interaction between lithium and angiotensin-converting enzyme (ACE) inhibitors was investigated in a retrospective, longitudinal, case-control study of 20 hypertensive patients previously stabilized on lithium therapy. The objective of the study was to determine the impact of ACE inhibition on steady-state lithium concentrations and to evaluate the potential association of altered lithium clearance with age, renal function, and electrolyte balance. After initiation of the ACE inhibitor, steady-state lithium concentrations increased by 36.1%, lithium clearance was reduced by 25.5% (p < 0.0001), and four patients presented with symptoms suggestive of lithium toxicity. Significant bivariate correlations were observed for lithium clearance change and age (r = -0.45; p < 0.05) and for lithium clearance change and serum creatinine (r = -0.52; p < 0.02). Multiple regression analysis indicated that 25% of the change in lithium clearance was associated with a change in serum creatinine. This percentage was increased to 35% by the inclusion of age in the regression model. None of the other variables (age, height, weight, or change in serum sodium/potassium) made a significant contribution to this model. The authors concluded that a clinically important increase in lithium concentrations can occur in patients started on ACE inhibitor therapy. As elderly patients may be uniquely predisposed to this interaction, avoidance of this medication combination in older populations should be considered.

Clinical relevance of drug interactions with lithium

Although lithium continues to be regarded as the treatment of choice for bipolar disorders, the clinical use of this mood stabiliser is associated with an extremely narrow therapeutic range. Relatively minor increases in serum concentrations may induce serious adverse sequelae, and concentrations within the therapeutic range may result in toxic reactions. The safety of combining lithium with other medications, therefore, is a major concern, and extensive clinical experience has served to identify several significant drug interactions. Lithium removal from the body is achieved almost exclusively via renal means. As a result, any medication that alters glomerular filtration rates or affects electrolyte exchange in the nephron may influence the pharmacokinetic disposition of lithium. Concomitant use of diuretics has long been associated with the development of lithium toxicity, but the risk of significant interactions varies with the site of pharmacological action of the diuretic in the renal tubule. Thiazide diuretics have demonstrated the greatest potential to increase lithium concentrations, with a 25 to 40% increase in concentrations often evident after initiation of therapy. Osmotic diuretics and methyl xanthines appear to have the opposite effect on lithium clearance and have been advocated historically as antidotes for lithium toxicity. Loop diuretics and potassium-sparing agents have minor variable effects. Nonsteroidal anti-inflammatory drugs (NSAIDs) have also been associated with lithium toxicity, although the relative interactive potential of specific NSAIDs is difficult to determine. Small prospective studies have demonstrated large interindividual differences in lithium clearance values associated with different NSAIDs. A growing body of evidence also suggests that ACE inhibitors may impair lithium elimination, but further investigations are needed to identify patients at risk. Anecdotal reports have linked numerous medications with the development of neurotoxicity without an apparent effect on the pharmacokinetic disposition of lithium. Antipsychotics, anticonvulsants and calcium antagonists have all be implicated in a sufficient number of case reports to warrant concern. As these medications have all been commonly coadministered with lithium, the relative risk of serious interactions appears to be quite low, but caution is advised.

Drug-induced renal disease

OBJECTIVE

To review drug-induced renal disease with emphasis on current issues and practical problems with commonly used agents.

DATA SOURCES

English language literature search using MEDLINE, Index Medicus, textbook articles and relevant reviews.

STUDY SELECTION

Drugs in common use were reviewed in detail. Uncommonly used drugs or those with only a few reports of nephrotoxicity were excluded from this review.

DATA SYNTHESIS

The clinical patterns of nephrotoxicity include an episode of acute deterioration of renal function, chronic renal failure and proteinuria which may be severe enough to cause the nephrotic syndrome. Diagnosis is made by clinical suspicion, distinctive clinical patterns and usually improvement in renal function on drug withdrawal.

CONCLUSION

A high index of suspicion is necessary to detect drug-induced renal disease particularly with increasing availability of over-the-counter drugs. Drugs should always be suspected of causing renal disease where no alternative cause is obvious. When any doubt exists the agent in question should be withdrawn.