Calcium channel blocker use and mortality among patients with end-stage renal disease

Antihypertensive Drug Treatment and the Risk for Intrahemodialysis Hypotension

Key Points

Antihypertensive medications are often used by hemodialysis patients, and intradialytic hypotension is a common complication in these patients. The study emulates a randomized clinical trial comparing antihypertensive drug treatment for the risk of hemodialysis hypotension in 4072 incident patients. Compared with calcium antagonists, β and α –β blockers, angiotensin converting enzyme inhibitors or angiotensin II antagonists, and diuretics may increase the risk of hemodialysis hypotension.

Background

Antihypertensive medications are often prescribed to manage hypertension in hemodialysis patients, and intradialytic hypotension (IDH) is a common complication in these patients. We investigated the risk of IDH in incident hemodialysis patients who initiated treatment with antihypertensive drugs in monotherapy.

Methods

The study was conducted as an emulation of a randomized clinical trial in 4072 incident hemodialysis patients who started antihypertensive drug treatment between January 2016 and December 2019. The primary outcome was the occurrence of IDH during hemodialysis sessions. The generalized estimating equation analysis was adjusted by inverse probability treatment weighting.

Results

Calcium channel blocker (CCB) use was associated with an IDH incidence rate of 7.4 events per person-year (95% confidence interval [CI], 6.2 to 8.6). Compared with CCB use, use of β and α –β blockers was strongly associated with a higher likelihood of IDH (odds ratio [OR] [95% CI, 2.27; 1.50 to 3.43]). The use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (OR [95% CI, 1.71; 1.14 to 2.57]) and diuretics (OR [95% CI, 1.52; 1.07 to 2.16]) were also associated with a higher likelihood of IDH compared with CCB use.

Conclusions

The study suggests that using β and α –β blockers, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, and diuretics may increase the risk of IDH in hemodialysis patients compared with CCB use.

Genetically determined blood pressure, antihypertensive drug classes, and frailty: A Mendelian randomization study

Observational studies have suggested that the use of antihypertensive drugs was associated with the risk of frailty; however, these findings may be biased by confounding and reverse causality. This study aimed to explore the effect of genetically predicted lifelong lowering blood pressure (BP) through different antihypertensive medications on frailty. One-sample Mendelian randomization (MR) and summary data-based MR (SMR) were applied. We utilized two kinds of genetic instruments to proxy the antihypertensive medications, including genetic variants within or nearby drugs target genes associated with systolic/diastolic BP, and expression level of the corresponding gene. Among 298,618 UK Biobank participants, one-sample MR analysis observed that genetically proxied BB use (relative risk ratios, 0.76; 95% CI, 0.65-0.90; p = 0.001) and CCB use (0.83; 0.72-0.95; p = 0.007), equivalent to a 10-mm Hg reduction in systolic BP, was significantly associated with lower risk of pre-frailty. In addition, although not statistically significant, the effect directions of systolic BP through ACEi variants (0.72; 0.39-1.33; p = 0.296) or thiazides variants (0.74; 0.53-1.03; p = 0.072) on pre-frailty were also protective. Similar results were obtained in analyses for diastolic BP. SMR of expression in artery showed that decreased expression level of KCNH2, a target gene of BBs, was associated with lower frailty index (beta -0.02, p = 2.87 × 10-4). This MR analysis found evidence that the use of BBs and CCBs was potentially associated with reduced frailty risk in the general population, and identified KCNH2 as a promising target for further clinical trials to prevent manifestations of frailty.

Association of Calcium Channel Blocker Use With Intradialytic Hypotension in Maintenance Hemodialysis

Introduction

Calcium channel blockers (CCBs) are common antihypertensive agents among patients receiving hemodialysis (HD). Despite this, the association of CCBs with intradialytic hypotension (IDH), an important adverse outcome that is associated with cardiovascular morbidity and mortality, remains largely unexplored.

Methods

Using kinetic modeling sessions data from the Hemodialysis (HEMO) Study, random effects regression models were fit to assess the association of CCB use versus nonuse with IDH (defined as systolic blood pressure [SBP] < 90 mm Hg if pre-HD SBP < 160 mm Hg or < 100 mm Hg if pre-HD SBP ≥160 mm Hg). Models were adjusted for age, biological sex (distinguishing between males and females), race, randomized Kt/V and flux assignments, heart failure, ischemic heart disease, peripheral vascular disease, diabetes mellitus, blood urea nitrogen, ultrafiltration rate, access type, pre-HD SBP, and other antihypertensives.

Results

Data were available for 1838 patients and 64,538 sessions. At baseline, 49% of patients were prescribed CCBs. The overall frequency of IDH was 14% with a mean decline from pre- to nadir-SBP of 33 ± 15 mm Hg. CCB use was associated with lower adjusted risk of IDH, compared with no use (incidence rate ratio [IRR]: 0.84; 95% confidence interval [CI]: 0.78-0.89). The association was most pronounced for those in the pre-HD SBP lowest quartile (IRR: 0.77; 95% CI: 0.70-0.85); compared with the highest quartile (IRR: 0.86; 95% CI: 0.77-0.97; P-interaction < 0.001).

Conclusion

Among patients receiving HD, CCB use was associated with a lower risk of developing IDH, independent of pre-HD SBP and other antihypertensives use. Mechanistic studies are needed to better understand the effects of CCB and other antihypertensives on peridialytic blood pressure (BP) parameters among patients receiving HD.

The proportion of chronic kidney disease and its associated factors among adult diabetic patients at Tibebe Ghion Specialized Hospital, Bahir Dar, Ethiopia

Background

Chronic kidney disease is defined as a progressive loss of kidney function occurring over several months to years. Programs to detect chronic kidney disease, linked to comprehensive primary and secondary Prevention strategies are rare in our country. This study aimed to assess the proportion of chronic kidney disease and its associated factors among adult diabetic patients.

Methods

An institutional-based cross-sectional study design was used. Adult Diabetic Patients (≥18 years of age) coming to the medical outpatient clinic were considered as study participants and they were selected using a systematic random sampling technique. Data were checked for completeness, then entered into Epi Data 3.1, and exported to SPSS Version 24 for analysis. Descriptive statistics such as frequency, crosstab, and median were utilized. chronic kidney disease epidemiology collaboration equations for calculating estimated glomerular filtration rate Simple binary logistic regression was conducted to identify candidate variables for multiple binary logistic regression at a p-value of <0.2. Those variables whose P-value <0.05 in multiple binary logistic regression were considered as significantly associated variables with chronic kidney diseases.

Result

A total of 329 individuals were participating in the study. Of which 199 (60.5%) were males. The median age of participants was 39 (IQR; 28: 56) years. Of the total participants, 125(38%) had no formal education. The proportion of chronic kidney disease was 16.7% (95% CI: 12.8%–21%), The study also found that older age (AOR = 3.02; 95%CI: 1.37, 6.69), pre-existing hypertension (AOR = 4.85; 95%CI: 2.07, 11.3), current systolic blood pressure ≥140mmHg (AOR = 6.33, 95%CI: 3.34, 11.99), and presence of Albuminuria (AOR = 2.98, 95%CI: 1.26, 7.09) were associated with chronic kidney disease.

Conclusions

The proportion of CKD among diabetic patients in Tibebe Ghion Specialized Hospital was relatively high as compared to other studies. Health care professionals should consider strict follow-up for older age patients, patients with co-morbidities like hypertension, and for those patients with Albuminuria.

Biomarkers of Uremic Cardiotoxicity

Cardiovascular (CV) morbidity and mortality increase along with the progression of chronic kidney disease (CKD). The potential novel biomarkers of cardiotoxicity have been tested with the aim of the early detection of patients at high CV risk, and among them are markers of inflammation, oxidative stress, acute renal injury, and microRNAs. The study analyzed biomarkers in non-dialysis-dependent (NDD; stage 3a-4 CKD) and dialysis-dependent (DD) CKD patients. The prospective cohort study included 87 patients who were followed for 18 months, during which period newly occurred CV events were recorded. Cox regression analysis confirmed serum albumin, urea, interventricular septum thickness diameter (IVST), the use of calcium antagonist, and erythropoiesis-stimulating agent to be significant predictors of CV outcome. No significant difference was observed in biomarkers of inflammation, oxidative stress, acute kidney injury (IL-18, CRP, ferritin, IMA, SOD, NGAL, and KIM-1), and miR-133a, in regards to the presence/absence of CV event, CV death, and left ventricular hypertrophy. Serum albumin, urea, IVST, and the use of calcium antagonist and erythropoiesis-stimulating agents were confirmed to be factors associated with CV events in CKD patients. Apart from traditional risk factors, new research is needed to define novel and reliable biomarkers of cardiotoxicity in CKD patients.

Sudden cardiac death in dialysis patients: different causes and management strategies

Sudden cardiac death (SCD) represents a major cause of death in end-stage kidney disease (ESKD). The precise estimate of its incidence is difficult to establish because studies on the incidence of SCD in ESKD are often combined with those related to sudden cardiac arrest (SCA) occurring during a haemodialysis (HD) session. The aim of the European Dialysis Working Group of ERA-EDTA was to critically review the current literature examining the causes of extradialysis SCD and intradialysis SCA in ESKD patients and potential management strategies to reduce the incidence of such events. Extradialysis SCD and intradialysis SCA represent different clinical situations and should be kept distinct. Regarding the problem, numerically less relevant, of patients affected by intradialysis SCA, some modifiable risk factors have been identified, such as a low concentration of potassium and calcium in the dialysate, and some advantages linked to the presence of automated external defibrillators in dialysis units have been documented. The problem of extra-dialysis SCD is more complex. A reduced left ventricular ejection fraction associated with SCD is present only in a minority of cases occurring in HD patients. This is the proof that SCD occurring in ESKD has different characteristics compared with SCD occurring in patients with ischaemic heart disease and/or heart failure and not affected by ESKD. Recent evidence suggests that the fatal arrhythmia in this population may be due more frequently to bradyarrhythmias than to tachyarrhythmias. This fact may partly explain why several studies could not demonstrate an advantage of implantable cardioverter defibrillators in preventing SCD in ESKD patients. Electrolyte imbalances, frequently present in HD patients, could explain part of the arrhythmic phenomena, as suggested by the relationship between SCD and timing of the HD session. However, the high incidence of SCD in patients on peritoneal dialysis suggests that other risk factors due to cardiac comorbidities and uraemia per se may contribute to sudden mortality in ESKD patients.

Blood pressure targets and pharmacotherapy for hypertensive patients on hemodialysis

INTRODUCTION

Hypertension is highly prevalent in patients with end-stage kidney disease on hemodialysis and is often not well controlled. Blood pressure (BP) levels before and after hemodialysis have a U-shaped relationship with cardiovascular and all-cause mortality. Although antihypertensive drugs are recommended for patients in whom BP cannot be controlled appropriately by non-pharmacological interventions, large-scale randomized controlled clinical trials are lacking.

AREAS COVERED

The authors review the pharmacotherapy used in hypertensive patients on dialysis, primarily focusing on reports published since 2000. An electronic search of MEDLINE was conducted using relevant key search terms, including 'hypertension', 'pharmacotherapy', 'dialysis', 'kidney disease', and 'antihypertensive drug'. Systematic and narrative reviews and original investigations were retrieved in our research.

EXPERT OPINION

When a drug is administered to patients on dialysis, the comorbidities and characteristics of each drug, including its dialyzability, should be considered. Pharmacological lowering of BP in hypertensive patients on hemodialysis is associated with improvements in mortality. β-blockers should be considered first-line agents and calcium channel blockers as second-line therapy. Renin-angiotensin-aldosterone system inhibitors have not shown superiority to other antihypertensive drugs for patients on hemodialysis.

Hypertension control among euvolemic hypertensive hemodialysis patients in Malaysia: a prospective follow-up study

Objectives

Existing literature does not provide enough information on evaluation of factors associated with pre-dialysis controlled hypertension among euvolemic hemodialysis (HD) patients. We conducted a study to evaluate the rate and factors influencing pre-dialysis controlled hypertension among euvolemic HD patients.

Design

A multicenter prospective follow-up study.

Setting

Tertiary care teaching hospital and its associated private dialysis centers.

Participants

This study included 145 euvolemic eligible hypertensive patients. Various sociodemographic, clinical factors and drugs were investigated and analyzed by using appropriate statistical methods to determine the factors influencing hypertension control among the study participants.

Results

On baseline visit, the mean pre-dialysis systolic and diastolic BP (mmHg) of study participants was 161.2 ± 24. and 79.21 ± 11.8 retrospectively, and 30 (20.6%) patients were on pre-dialysis goal BP. At the end of the 6-months follow-up, the mean pre-dialysis systolic BP and diastolic BP (mmHg) of the patients was 154.6 ± 18.3 and 79.2 ± 11.8 respectively, and 42 (28.9%) were on pre-dialysis goal BP. In multivariate analysis, the use of calcium channel blockers (CCBs) was the only variable which had statistically significant association with pre-dialysis controlled hypertension at baseline (OR = 7.530, p-value = 0.001) and final (OR = 8.988, p-value < 0.001) visits.

Conclusions

In present study, the positive association observed between CCBs and controlled hypertension suggests that CCBs are effective antihypertensive drugs in the management of hypertension among euvolemic HD patients.

Strengths and limitations of this study

This study involved a group of patients from tertiary-level teaching hospital and its associated private dialysis centers of Malaysia.To the best of the authors' knowledge, this is the first study to assess the factors influencing pre-dialysis controlled hypertension in a cohort of 145 euvolemic HD patients in a Malaysian setting.For determining the factors influencing hypertenion control multivariate analysis was conducted.Being a prospective follow-up study, the findings of the present study need to be interpreted with caution since it is limited to only 6 months follow up.Nevertheless, a multicenter study with a large sample size and longer follow up time is needed to confirm the findings of the current study.

Calcium Channel Blocker-Associated Chyloperitoneum in Patients Receiving Peritoneal Dialysis: A Systematic Review

Unlike chyloperitoneum associated with clinical conditions including cancer, cirrhosis, and traumatic surgery, calcium channel blocker (CCB)-associated chyloperitoneum is rarely discussed in comprehensive studies on chyloperitoneum. We aimed to investigate the prevalence and characteristics of CCB-associated chyloperitoneum in peritoneal dialysis (PD) patients. The MEDLINE, Embase, CENTRAL, CiNii, and RISS databases were systematically searched for clinical studies on CCB-associated chyloperitoneum in PD patients published up to 31 July 2018. A total of 17 studies (four cohort studies, one case series, and 12 case reports) were selected. Eight CCBs, namely amlodipine, benidipine, diltiazem, lercanidipine, manidipine, nifedipine, nisoldipine, and verapamil, were reported to be associated with chyloperitoneum; manidipine and lercanidipine were the most frequently reported. The average prevalence of chyloperitoneum for lercanidipine was 25.97% in three cohort studies, two of which had a moderate or high risk of bias. Most of the studies revealed chyloperitoneum development within 4 days of initiation of CCB therapy and chyloperitoneum disappearance within 24 h of CCB withdrawal. The results of this study emphasise on the need for awareness among healthcare professionals regarding CCB-associated chyloperitoneum in PD patients. Further studies elucidating the causality and clinical implication of CCB-associated chyloperitoneum are needed.

Effect of Anti-Hypertensive Medication History on Arteriovenous Fistula Maturation Outcomes

BACKGROUND

The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis. However, approximately half of AVFs fail to mature. The use of angiotensin converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and calcium channel blockers (CCBs) exerts favorable endothelial effects and may promote AVF maturation. We tested associations of ACE-I and ARBs, CCBs, beta-blockers, and diuretics with the maturation of newly created AVFs.

METHODS

We evaluated 602 participants from the Hemodialysis Fistula Maturation Study, a multi-center, prospective cohort study of AVF maturation. We ascertained the use of each medication class within 45 days of AVF creation surgery. We defined maturation outcomes by clinical use within 9 months of surgery or 4 weeks of initiating hemodialysis.

RESULTS

Unassisted AVF maturation failure without intervention occurred in 54.0% of participants, and overall AVF maturation failure (with or without intervention) occurred in 30.1%. After covariate adjustment, CCB use was associated with a 25% lower risk of overall AVF maturation failure (95% CI 3%-41% lower) but a non-significant 10% lower risk of unassisted maturation failure (95% CI 23% lower to 5% higher). ACE-I/ARB, beta-blocker, and diuretic use was not significantly associated with AVF maturation outcomes. None of the antihypertensive medication classes were associated with changes in AVF diameter or blood flow over 6 weeks following surgery.

CONCLUSIONS

CCB use may be associated with a lower risk of overall AVF maturation failure. Further studies are needed to determine whether CCBs might play a causal role in improving AVF maturation outcomes.

Practice patterns in transitioning patients from chronic kidney disease to dialysis: a survey of United States nephrologists

Background

There are no guidelines for transitioning patients from chronic kidney disease stage 5 to hemodialysis. We conducted this study to determine if there are uniform patterns in how nephrologists transition patients to dialysis.

Methods

We designed an electronic survey with 39 questions and sent it to a database of practicing nephrologists at the National Kidney Foundation. Factors that were important for transitioning a patient to hemodialysis were evaluated, including medication changes on dialysis initiation, dry weight and dialysis prescription.

Results

160 US Nephrologists replied to the survey; 18% (29/160) of the responses were completed via social media sites. Prior to dialysis, 74% (118/160), prescribed furosemide and 67% (107/160) used furosemide with metolazone. Once dialysis started, only 46% (74/160) of the responders continued patients on diuretics daily. Hypertension medications prescribed in dialysis were calcium channel blockers 69% (112/160), beta blockers 36% (58/160), angiotensin converting enzyme inhibitor 32% (53/160), angiotensin receptor blocker 29% (46/160) and diuretics 25% (42/160). Once dialysis started, 68% (109/160) routinely changed medications. Most, 67% (107/160) ordered patients to avoid anti-hypertensive medications on dialysis days to allow for ultrafiltration. Dry weight was determined in the first week by 29% (46/160) and in the first month by 53% (85/160). Most, 59% (94/160) felt that multiple causes lead to hypertension. Most nephrologists would prescribe small dialyzers and a shorter period of time for the first dialysis session.

Conclusion

The transition period to chronic hemodialysis has variations in practice patterns and may benefit from further studies to optimize clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-0943-0) contains supplementary material, which is available to authorized users.

Impact of drugs on intradialytic hypotension: Antihypertensives and vasoconstrictors

Intradialytic hypotension (IDH) is a common complication of hemodialysis and is associated with numerous adverse outcomes including cardiovascular events, inadequate dialysis, loss of vascular access, and death. It is estimated that approximately 20%-30% of all dialysis sessions are affected by IDH. In seeking ways to reduce the occurrence of IDH, dialysis providers often turn to pharmacological approaches: withholding antihypertensive medications prior to hemodialysis or administering vasoconstrictor medications. This review will focus on what is known about the relation between antihypertensive medications and IDH, and summarize studies that have examined the efficacy of vasoconstrictor medications on IDH, including midodrine, arginine vasopressin, and droxidopa. However, there is currently scant evidence that any pharmacological approach is particularly effective in reducing IDH. Additional studies of potential treatments for IDH are needed, and should examine not only hemodynamic effects such as changes in nadir blood pressure during dialysis, but also on patient-centered and clinical outcomes such as symptoms of IDH, quality of life, and cardiovascular events.

Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use and cardiovascular outcomes in patients initiating peritoneal dialysis

Background

Data on the effectiveness of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in reducing cardiovascular (CV) risk in patients undergoing peritoneal dialysis (PD) are limited. We investigated the association between ACEI/ARB use and CV outcomes in patients initiating PD.

Methods

In this observational cohort study, we identified from the United States Renal Data System all adult patients who initiated PD from 2007 to 2011 and participated in Medicare Part D, a federal prescription drug benefits program, for the first 90 days of dialysis. Patients who filled a prescription for an ACEI or ARB in those 90 days were considered users. We applied Cox regression to an inverse probability of treatment weighted cohort to estimate the hazard ratios (HRs) for the combined outcome of death, ischemic stroke or myocardial infarction (MI) and each outcome individually.

Results

Among 4879 patients, 2063 (42%) used an ACEI/ARB. Patients were followed up for a median of 1.2 years. We recorded 1771 events, for a composite rate of 25 events per 100 person-years. ACEI/ARB use (versus nonuse) was associated with a reduced risk of the composite outcome {HR 0.84 [95% confidence interval (CI) 0.76-0.93]}, all-cause mortality [HR 0.83 (95% CI 0.75-0.92)] and CV death [HR 0.74 (95% CI 0.63-0.87)], but not MI [HR 0.88 (95% CI 0.69-1.12)] or ischemic stroke [HR 1.06 (95% CI 0.79-1.43)]. Results were similar in as-treated analyses. In a subgroup analysis, we did not find any effect modification by residual renal function.

Conclusions

ACEI/ARB use is common in patients initiating PD and is associated with a lower risk of fatal CV outcomes.

Differential impact of smoking on mortality and kidney transplantation among adult Men and Women undergoing dialysis

BACKGROUND

The extent to which smoking contributes to adverse outcomes among men and women of all ages undergoing dialysis is uncertain. The objective of this study was to determine the differential impact of smoking on risks of mortality and kidney transplantation by age and by sex at dialysis initiation.

METHODS

We conducted a population-based cohort of incident U.S dialysis patients (n = 1, 220, 000) from 1995-2010. Age- and sex-specific mortality and kidney transplantation rates were determined for patients with and without a history of cardiovascular disease. Multivariable Cox regression evaluated relative hazard ratios (HR) for death and kidney transplantation at 2 years stratified by atherosclerotic condition, smoking status and age. Analyses were adjusted for demographic characteristics, non-cardiovascular conditions, laboratory variables, socioeconomic and lifestyle factors.

RESULTS

The average age was 62.8 (±15) years old, 54 % were male, and the majority was white. During 2-year follow-up, 40.5 % died and 5.7 % were transplanted. Age- and sex-specific mortality rates were significantly higher while transplantation rates were significantly lower for smokers with atherosclerotic conditions than non-smokers (P < 0.01). The adjusted mortality hazards were significantly higher for smokers with pre-existing coronary disease (HR 1.15, 95 % CI (1.11-1.18), stroke (HR 1.21, 1.16-1.27) and peripheral vascular disease (HR = 1.21, 1.17-1.25) compared to non-smokers without these conditions (HR 1.00, referent group). The magnitude of effect was greatest for younger patients than older patients. Contrastingly, the adjusted risks of kidney transplantation were significantly lower for smokers with coronary disease: (HR 0.60, 0.52-0.69), stroke; (HR 0.47, 0.37-0.60), and peripheral arterial disease (HR 0.55, 0.46-0.66) respectively compared to non-smokers without these conditions.

CONCLUSIONS

We provide compelling evidence that smoking is associated with adverse clinical outcomes and reduced lifespans among dialysis patients of all ages and sexes. The adverse impact is greatest for younger men and women.

Use of Calcium Channel Blockers is Associated with Mortality in Patients with Chronic Kidney Disease

BACKGROUND/AIMS

The use of antihypertensive medicines has been shown to reduce proteinuria, morbidity, and mortality in patients with chronic kidney disease (CKD). A specific recommendation for a class of antihypertensive drugs is not available in this population, despite the pharmacodynamic differences. We have therefore analysed the association between antihypertensive medicines and survival of patients with chronic kidney disease.

METHODS

Out of 2687 consecutive patients undergoing kidney biopsy a cohort of 606 subjects with retrievable medical therapy was included into the analysis. Kidney function was assessed by glomerular filtration rate (GFR) estimation at the time point of kidney biopsy. Main outcome variable was death.

RESULTS

Overall 114 (18.7%) patients died. In univariate regression analysis the use of alpha-blockers and calcium channel antagonists, progression of disease, diabetes mellitus (DM) type 1 and 2, arterial hypertension, coronary heart disease, peripheral vascular disease, male sex and age were associated with mortality (all p<0.05). In a multivariate Cox regression model the use of calcium channel blockers (HR 1.89), age (HR 1.04), DM type 1 (HR 8.43) and DM type 2 (HR 2.17) and chronic obstructive pulmonary disease (HR 1.66) were associated with mortality (all p < 0.05).

CONCLUSION

The use of calcium channel blockers but not of other antihypertensive medicines is associated with mortality in primarily GN patients with CKD.

Association between higher rates of cardioprotective drug use and survival in patients on dialysis

BACKGROUND

While cardiovascular (CV) disease is a leading cause of morbidity and mortality in patients on chronic dialysis, utilization rates of cardioprotective drugs for dialysis patients remain low. This study sought to determine whether higher rates of cardioprotective drug use among dialysis patients might increase survival.

METHODS

A retrospective cohort of incident dialysis patients (n = 50,468) with dual eligibility for U.S. Medicare and Medicaid was constructed using USRDS data linked with billing claims. Medication exposures included angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs), β-blockers, calcium channel blockers (CCBs), and HMG-CoA reductase inhibitors (statins) prescribed within 90 days of dialysis initiation. The outcomes were one- and two-year survival and CV event-free survival. Variation in treatment rates based on local area practice styles were used as instruments in instrumental variable (IV) estimation, yielding average treatment effect estimates for patients whose treatment choices were affected by local area practice styles.

RESULTS

Patients aged 65 years and older comprised 47.4% of the sample, while 59.5% were female and 35.0% were white. The utilization rate was 40.7% for ACEIs/ARBs, 43.0% for β-blockers, 50.7% for CCBs and 26.4% for statins. The local area practice style instruments were highly significantly related to cardioprotective drug use in dialysis patients (Chow-F values > 10). IV estimates showed only that higher rates of β-blockers increased one-year survival (β = 0.161, P-value = 0.020) and CV event-free survival (β = 0.189, P-value = 0.033), but that higher rates of CCBs decreased two-year CV event-free survival (β = -0.520, P-value = 0.009).

CONCLUSIONS

This study suggests that higher utilization rates of β-blockers might yield higher survival rates for dialysis patients. However, higher rates of the other drugs studied had no correlations with survival, and higher CCB rates might actually reduce CV-event free survival. Since the benefits of cardioprotective drugs may vary across dialysis patients, the study findings should be interpreted only with respect to changes of utilization rates around the rates observed in this study.

Impact of use of angiotensin II receptor blocker on all-cause mortality in hemodialysis patients: prospective cohort study using a propensity-score analysis

BACKGROUND

It is controversial whether treatment with an angiotensin II receptor blocker (ARB) or a calcium channel blocker (CCB) improves prognosis of hemodialysis (HD) patients.

METHODS

This study was designed as a multicenter prospective cohort study. HD patients (n = 1071) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data, kidney transplantation or retraction of consent during the follow-up period (n = 204) were excluded, and 867 patients contributed to analysis of mortality. Propensity score (PS) for use of ARB and that for CCB was calculated using a multiple logistic regression model.

RESULTS

ARB and CCB were prescribed in 45.6 and 54.7 % of patients at enrollment. During the 3-year follow-up period, all-cause mortality and cardiovascular mortality rates were 18.8 and 5.1 %, respectively. Kaplan-Meier curves showed that all-cause and cardiovascular mortality rates were lower in the ARB group than in the non-ARB group, though the mortality rates were similar in the CCB group and non-CCB group. In PS-stratified Cox regression analysis, ARB treatment was associated with 34 and 45 % reduction of all-cause death and cardiovascular death, respectively. In PS matching analysis, ARB treatment was associated with a significant reduction (46 % reduction) in the risk of all-cause death. A significant impact of CCB treatment on all-cause or cardiovascular mortality was not detected in PS analysis.

CONCLUSIONS

The use of an ARB, but not a CCB, is associated with reduced all-cause and cardiovascular mortalities in patients on HD.

Relationship between calcium channel blocker class and mortality in dialysis

BACKGROUND AND OBJECTIVE

The comparative effectiveness of dihydropyridine (DHP) and non-DHP calcium channel blockers (CCBs) in maintenance dialysis patients has not been well-studied.

METHODS

A retrospective cohort of hypertensive patients initiating dialysis was created. New CCB initiators, defined as individual who had no evidence of CCB use in the first 90 days of dialysis but who were initiated by day 180, were followed from their first day of medication exposure until event or censoring; events consisted of all-cause mortality (ACM) and a combined endpoint of cardiovascular morbidity or mortality (CVMM). Cox proportional hazards models were used to determine adjusted hazard ratios (AHRs) comparing the effect of DHPs vs. non-DHPs.

RESULTS

There were 2900 and 2704 new initiators of CCBs in the ACM and CVMM models, respectively. Adjusted for other factors, use of DHPs, compared to non-DHPs, was associated with an AHR of 0.77 (99% confidence intervals, 0.64 - 0.93, P = 0.0004) for ACM and 0.86 (0.72 - 1.02, P = 0.024) for CVMM. Results were similar when individuals who initiated therapy at any point after the cohort inception were included, with AHRs of 0.60 (0.53 - 0.69, P < 0.0001) and 0.77 (0.67 - 0.89, P < 0.0001) for ACM and CVMM, respectively. Further, elimination of individuals with chronic atrial fibrillation resulted in AHRs of 0.71 and 0.70 for ACM and CVVM, respectively.

CONCLUSION

DHPs, as compared to non-DHPs, were associated with reduced hazard of death or cardiovascular morbidity and mortality; potential mechanisms of action require further study.

Sudden cardiac death in CKD patients

The risk of sudden cardiac death (SCD) is high in chronic kidney disease patients, and it increases with the progression of kidney function deterioration. The most common causes of SDC are the following: ventricular tachycardia, ventricular tachyarrhythmia, tachycardia torsade de pointes, sustained ventricular fibrillation and bradyarrhythmia. Dialysis influences cardiovascular system and results in hemodynamic disturbances as well as electrolyte shifts altering myocardial electrophysiology. Studies suggest that this procedure exerts both detrimental (poor volume control can exacerbate hypertension and left ventricle hypertrophy) and beneficial effects (associated with fluid removal and subsequent decrease in left ventricle stretch). Dialysis-related vulnerability to serious arrhythmias is the result of sudden shifts in fluid status and electrolytes, particularly potassium, which alter the physiological milieu. Also Ca(2+) ions, in which concentration alters during dialysis, are of key importance in the contraction of vascular smooth muscle cells and cardiac myocytes, thus exerting significant effects on hemodynamics. Due to the fact that SCD occurs with similar frequency in peritoneal dialysis and in hemodialysis patients, it seems that end-stage renal disease factors are more important than the specific ones associated with dialysis type. The results of randomized trials suggested that hemodialysis patients may not derive the same benefit of cardiovascular disease therapy including beta-blockers, calcium channel blockers and angiotensin-converting enzyme inhibitors as the general population with normal kidney function. Noninvasive tests used to stratify SCD risk in HD patients have poor positive value, and thus, combining tests including HRV, baroreceptor sensitivity and effectiveness index as well as its function indices and heart rate turbulence should be implemented. There are only few large randomized placebo-controlled trials assessing the influence of cardioprotective medications or implantable cardioverter defibrillator (ICD) implantation in dialysis patients on life quality and survival, and their results are sometimes contradictory. The decision concerning treatment and/or ICD implantation in this group of patients should be made on the basis of careful assessment of individual risk factors. Moreover, due to the high hazard of cardiovascular mortality including SCD in dialysis patients, physicians should concentrate on the early selection of high-risk patients, monitoring them and introduction of preventive measures.

Antihypertensive medication exposure and cardiovascular outcomes in hemodialysis patients

BACKGROUND/AIMS

Our understanding of the effectiveness of cardioprotective medications in maintenance dialysis patients is based upon drug exposures assessed at a single point in time. We employed a novel, time-dependent approach to modeling medication use over time to examine outcomes in a large national cohort.

METHODS

We linked Medicaid prescription claims with United States Renal Data System registry data and Medicare claims for 52,922 hypertensive maintenance dialysis patients. All-cause mortality and a combined cardiovascular disease (CVD)-endpoint were modeled as functions of exposure to cardioprotective antihypertensive medications (renin angiotensin system antagonists, β-adrenergic blockers, and calcium channel blockers) measured with three time-dependent covariates (weekly exposure status, proportion of prior weeks with exposure, and number of switches in exposure status) and with propensity adjustment.

RESULTS

Current cardioprotective medication exposure status as compared to not exposed was associated with lower adjusted hazard ratios (AHRs) for mortality, though the magnitude depended upon the proportion of prior weeks with medication (duration) and the number of switches between active and non-active use (switches) (AHR range 0.54-0.90). Combined CVD-endpoints depended upon the proportion of weeks on medication: AHR = 1.18 for 10% and AHR = 0.90 for 90% of weeks. Combined CVD-endpoint was also lower for patients with fewer switches.

CONCLUSIONS

Effectiveness depends not only on having a drug available but is tempered by duration and stability of use, likely reflecting variation in clinical stability and patient behavior.

Medication among patients with type 1 diabetes and predialytic renal disease

AIMS

To examine use and changes of medication in the three years before start of chronic renal replacement therapy (RRT) among patients with type 1 diabetes, and the association between predialytic medication and survival on RRT.

METHODS

We recorded medication of 496 patients with type 1 diabetes before and after start of RRT in 2000-2006 and followed up until death or end of 2009. Data were retrieved from the Finnish Registry for Kidney Diseases and from the FinDM diabetes database. We evaluated the use of renin-angiotensin system (RAS) blockers, calcium channel blockers, β-blockers, statins, vitamin D, erythropoiesis-stimulating agents, and phosphate binders over three years. The association between predialytic medication and survival was assessed using Cox proportional hazards regression.

RESULTS

Medication increased markedly with progressing renal insufficiency. Almost 70% of the patients used calcium channel blockers and β-blockers before initiating RRT. Use of calcium channel blockers (RR 0.72, 95% CI 0.53-0.95) and vitamin D (RR 0.70, 95% CI 0.52-0.94) at start of RRT were associated with better survival when adjusted for age and sex, but after further adjustment the association lost statistical significance.

CONCLUSIONS

Among type 1 diabetes patients in the predialysis phase, use of medication is abundant. Use of medication appears to keep patients at an equal survival level to those without the same medication. However, due to the observational nature of our study, conclusions regarding the effect of medication on survival must be made with caution.

Patterns in blood pressure medication use in US incident dialysis patients over the first 6 months

BACKGROUND

Several observational studies have evaluated the effect of a single exposure window with blood pressure (BP) medications on outcomes in incident dialysis patients, but whether BP medication prescription patterns remain stable or a single exposure window design is adequate to evaluate effect on outcomes is unclear.

METHODS

We described patterns of BP medication prescription over 6 months after dialysis initiation in hemodialysis and peritoneal dialysis patients, stratified by cardiovascular comorbidity, diabetes, and other patient characteristics. The cohort included 13,072 adult patients (12,159 hemodialysis, 913 peritoneal dialysis) who initiated dialysis in Dialysis Clinic, Inc., facilities January 1, 2003-June 30, 2008, and remained on the original modality for at least 6 months. We evaluated monthly patterns in BP medication prescription over 6 months and at 12 and 24 months after initiation.

RESULTS

Prescription patterns varied by dialysis modality over the first 6 months; substantial proportions of patients with prescriptions for beta-blockers, renin angiotensin system agents, and dihydropyridine calcium channel blockers in month 6 no longer had prescriptions for these medications by month 24. Prescription of specific medication classes varied by comorbidity, race/ethnicity, and age, but little by sex. The mean number of medications was 2.5 at month 6 in hemodialysis and peritoneal dialysis cohorts.

CONCLUSIONS

This study evaluates BP medication patterns in both hemodialysis and peritoneal dialysis patients over the first 6 months of dialysis. Our findings highlight the challenges of assessing comparative effectiveness of a single BP medication class in dialysis patients. Longitudinal designs should be used to account for changes in BP medication management over time, and designs that incorporate common combinations should be considered.

Exercise perspective on common cardiac medications

Medicinal tablets have been used for a long time to treat cardiovascular disease. However, mortality rate is steadily increasing partly because of the patients’ sedentary lifestyle and unhealthy diet. By contrast, exercise has been systematically shown to have multiple benefits. Regular exercise training can prevent various diseases in healthy individuals. Combined exercise and cardiac medications may lead to the improvement of heart disease. Numerous exercise training pathways still need further investigations. How exercise can prevent, treat, or attenuate diseases remains somewhat elusive. Thus, this review will discuss cardiac medications in parallel with the mechanism of action of exercise.

Impact of race on cumulative exposure to antihypertensive medications in dialysis

BACKGROUND

Racial minorities typically have less exposure than non-minorities to antihypertensive medications across an array of cardiovascular conditions in the general population. However, cumulative exposure has not been investigated in dialysis patients.

METHODS

In a longitudinal analysis of 38,381 hypertensive dialysis patients, prescription drug data from Medicaid was linked to Medicare data contained in United States Renal Data System core data, creating a national cohort of dialysis patients dually eligible for Medicare and Medicaid services. The proportion of days covered (PDC) was calculated to determine cumulative exposure to angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), β-blockers, and calcium-channel blockers (CCDs). The factors associated with use of these medications were modeled through weighted linear regression, with derivation of the adjusted odds ratios (AORs) for exposure.

RESULTS

Relative to non-Hispanic Caucasians, African-American, Hispanic, or Other race/ethnicity were significantly associated with less exposure to β-blockers (AOR 0.56-0.69, P < 0.001 in each case) and CCBs (AOR 0.84-0.85, P < 0.001 in each case); African-American race and Hispanic ethnicity had AORs of 0.78 and 0.73 for ACEIs and ARBs, respectively (P < 0.001 in both cases). Collectively, the odds of exposure to each class of medication for minorities was about three-quarters of that for Caucasians.

CONCLUSIONS

Given that dually Medicare-and-Medicaid-eligible dialysis patients have insurance coverage for prescription medications as well as regular contact with health care providers, differences by race in exposure to antihypertensive medications should with time be minimal among patients who are candidates for these drugs. The causes of differences by race in exposure to antihypertensive medications over the course of time should be further examined.

Challenges in blood pressure measurement in patients treated with maintenance hemodialysis

The association between blood pressure and cardiovascular outcomes in patients undergoing hemodialysis remains controversial. This may relate in part to the technique and device used and the timing of the blood pressure measurement in relation to the hemodialysis procedure. Emerging evidence indicates that standardized hemodialysis unit blood pressure measurements or measurements obtained at home, either by the patient or using an ambulatory blood pressure monitor, may offer advantages over routine hemodialysis unit blood pressure measurements for determining cardiovascular risk and treatment. This review discusses the available evidence and implications for clinicians and clinical trials.

Impact of predialysis therapeutic practices on patient outcomes during the first year of dialysis: the Pharmacoepidemiologic AVENIR study

BACKGROUND

Studies evaluating patient outcomes in dialysis as a function of quality of predialysis therapeutic care are lacking.

OBJECTIVE

To evaluate the association of quality of predialysis therapeutic practices with survival and hospitalization during the first year of dialysis.

RESEARCH DESIGN

The AVantagE de la Néphroprotection dans l'Insuffisance Rénale study was an observational cohort study. Cox models explored the association between quality of therapeutic practices and survival over the first year whereas logistic regression measured the association with total duration of hospitalization (0 to 6 d, ≥7 d) among surviving patients at 1 year.

SUBJECTS

All adult patients with chronic kidney disease starting dialysis in Lorraine (France) between 2005 and 2006.

MEASURES

The appropriateness of therapeutic practices was evaluated with reference to current guidelines covering 5 aspects of chronic kidney disease: hypertension/proteinuria, anemia, bone disease, metabolic acidosis, and dyslipidemia. Each patient was then assigned a quality of therapeutic practices rating (high, moderate, or poor) depending on the number of aspects appropriately managed.

RESULTS

Quality of predialysis therapeutic practices was high in 18.2% of the 566 included patients, moderate in 62.5%, and poor in 19.3%. In multivariate analysis, the higher the quality of practices, the better the survival rate during the first year of dialysis [High: hazard ratio (HR) 1; moderate: HR 1.56, P=0.09; poor: HR 1.95, P=0.02]. Conversely, quality of therapeutic practices was not associated with duration of hospitalization among the 390 surviving patients at 1 year.

CONCLUSION

This study suggests that quality of predialysis therapeutic practices is positively associated with survival during the first year of dialysis.

Utilization and costs of cardiovascular disease medications in dialysis patients in Medicare Part D

BACKGROUND

Cardiovascular disease (CVD) is a major source of mortality and morbidity in dialysis patients. Population-level descriptions of CVD medication use are lacking in this population.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adult dialysis patients in the United States, alive on December 31, 2006, with Medicare Parts A and B and enrollment in Medicare Part D continuously in 2007.

PREDICTOR

CVDs and demographic characteristics.

OUTCOME

≥1 prescription fill during follow-up (2007).

MEASUREMENTS

Average out-of-pocket costs per user per month and average total drug costs per member per month were calculated.

RESULTS

Of 225,635 dialysis patients who met inclusion criteria during the entry period, 70% (n = 158,702) had continuous Part D coverage during follow-up. Of these, 76% received the low-income subsidy. β-Blockers were the most commonly used CVD medication (64%), followed by renin-angiotensin system inhibitors (52%), calcium channel blockers (51%), lipid-lowering agents (44%), and α-agonists (23%). Use varied by demographics, geographic region, and low-income subsidy status. For CVD medications, mean out-of-pocket costs per user per month were $3.44 and $49.59 and mean total costs per member per month were $124.02 and $110.32 for patients with and without the low-income subsidy, respectively.

LIMITATIONS

Information was available for only filled prescriptions under the Part D benefit; information for clinical contraindications was lacking, information for over-the-counter medications was unavailable, and medication adherence and persistence were not examined.

CONCLUSIONS

Most Medicare dialysis patients in 2007 were enrolled in Part D, and most enrollees received the low-income subsidy. β-Blockers were the most used CVD medication. Total costs of CVD medications were modestly higher for low-income subsidy patients, but out-of-pocket costs were much higher for patients not receiving the subsidy. Further study is warranted to delineate sources of variation in the use and costs of CVD medications across subgroups.

Angiotensin-converting enzyme inhibitors and cardiovascular outcomes in patients on maintenance hemodialysis

BACKGROUND

Persons with end-stage renal disease (ESRD) on hemodialysis carry an exceptionally high burden of cardiovascular disease. Angiotensin-converting enzyme inhibitors (ACEIs) are recommended for patients on dialysis, but there are few data regarding their effectiveness in ESRD.

METHODS

We conducted a secondary analysis of results of the HEMO study, a randomized trial of dialysis dose and membrane flux in patients on maintenance hemodialysis. We focused on the nonrandomized exposure of ACEI use, using proportional hazards regression and a propensity score analysis. The primary outcome was all-cause mortality. Secondary outcomes examined in the present analysis were cardiovascular hospitalization, heart failure hospitalization, and the composite outcomes of death or cardiovascular hospitalization and death or heart failure hospitalization.

RESULTS

In multivariable-adjusted analyses, there were no significant associations among ACEI use and mortality (hazard ratio 0.97, 95% CI 0.82-1.14), cardiovascular hospitalization, and either composite outcome. Angiotensin-converting enzyme inhibitor use was associated with a higher risk of heart failure hospitalization (hazard ratio 1.41, 95% CI 1.11-1.80). In the propensity score-matched cohort, ACEI use was not significantly associated with any outcomes, including heart failure hospitalization.

CONCLUSIONS

In a well-characterized cohort of patients on maintenance hemodialysis, ACEI use was not significantly associated with mortality or cardiovascular morbidity. The higher risk of heart failure hospitalization associated with ACEI use may not only reflect residual confounding but also highlights gaps in evidence when applying treatments proven effective in the general population to patients with ESRD. Our results underscore the need for definitive trials in ESRD to inform the treatment of cardiovascular disease.

Smoking in dialysis patients: a systematic review and meta-analysis of mortality and cardiovascular morbidity

BACKGROUND

Cigarette smoking is associated with increased cardiovascular morbidity and mortality in the general population, but the effect of smoking on these outcomes in the dialysis population is less well studied.

STUDY DESIGN

Systematic review and meta-analysis of cohort studies.

SETTING & POPULATION

Adults treated with long-term hemodialysis or peritoneal dialysis. SELECTION CRITERIA FOR INCLUDED STUDIES: Cohort studies of unselected dialysis patients reporting the association between smoking status and cardiovascular morbidity and/or mortality.

PREDICTOR

Smoking status (determined using patient report).

OUTCOMES

(1) All-cause or cardiovascular mortality; (2) incident cardiovascular events.

RESULTS

We identified 34 studies that fulfilled all inclusion criteria. Of these, 26 studies provided data for smoking and mortality and 10 (n = 6,538) were included in a meta-analysis. The pooled HR for all-cause mortality in smokers compared with nonsmokers was 1.65 (95% CI, 1.26-2.14; P < 0.001). 11 studies provided data for smoking and incident cardiovascular events; 5 (pooled n = 845) were included in a meta-analysis. The pooled HR for composite cardiovascular events in smokers compared with nonsmokers was 1.01 (95% CI, 0.98-1.05; P = 0.4).

LIMITATIONS

Data for these meta-analyses were heterogeneous. Few individual studies assessed smoking as the primary variable of interest.

CONCLUSIONS

Active smoking is associated with a significant increase in all-cause mortality in dialysis patients, although there was no corresponding increased risk of cardiovascular events.

Geographic variation in cardioprotective antihypertensive medication usage in dialysis patients

BACKGROUND

Despite their high risk of adverse cardiac outcomes, persons on long-term dialysis therapy have had lower use of antihypertensive medications with cardioprotective properties, such as angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs), β-blockers, and calcium channel blockers, than might be expected. We constructed a novel database that permits detailed exploration into the demographic, clinical, and geographic factors associated with the use of these agents in hypertensive long-term dialysis patients.

STUDY DESIGN

National cross-sectional retrospective analysis linking Medicaid prescription drug claims with US Renal Data System core data.

SETTING & PARTICIPANTS

48,882 hypertensive long-term dialysis patients who were dually eligible for Medicaid and Medicare services in 2005.

FACTORS

Demographics, comorbid conditions, functional status, and state of residence.

OUTCOMES

Prevalence of cardioprotective antihypertensive agents in Medicaid pharmacy claims and state-specific observed to expected ORs of medication exposure.

MEASUREMENTS

Factors associated with medication use were modeled using multilevel logistic regression models.

RESULTS

In multivariable analyses, cardioprotective antihypertensive medication exposure was associated significantly with younger age, female sex, nonwhite race, intact functional status, and use of in-center hemodialysis. Diabetes was associated with a statistically significant 28% higher odds of ACE-inhibitor/ARB use, but congestive heart failure was associated with only a 9% increase in the odds of β-blocker use and no increase in ACE-inhibitor/ARB use. There was substantial state-by-state variation in the use of all classes of agents, with a greater than 2.9-fold difference in adjusted-rate ORs between the highest and lowest prescribing states for ACE inhibitors/ARBs and a 3.6-fold difference for β-blockers.

LIMITATIONS

Limited generalizability beyond study population.

CONCLUSIONS

In publicly insured long-term dialysis patients with hypertension, there were marked differences in use rates by state, potentially due in part to differences in Medicaid benefits. However, geographic characteristics also were associated with exposure, suggesting clinical uncertainty about the utility of these medications.

Treatment of heart failure in long-term dialysis patients: a reappraisal

Heart failure is one of the most frequent cardiac complications in patients with end-stage renal disease receiving long-term hemodialysis or peritoneal dialysis and is associated strongly with a poor prognosis. Despite the significant morbidity and mortality associated with heart failure, there are very limited therapeutic options proved to prevent and treat heart failure in dialysis patients. This limitation largely reflects the paucity of adequately powered prospective randomized clinical trials that have examined the efficacy of different therapeutic options in long-term dialysis patients with heart failure. In this article, the second in a series discussing the management of heart failure in dialysis patients, current therapeutic options for heart failure in the maintenance dialysis population are reviewed and potential novel therapeutic options are discussed.

Blood pressure management in hemodialysis: what have we learned?

PURPOSE OF REVIEW

To review recent developments in the field of hypertension in hemodialysis patients.

RECENT FINDINGS

Despite the fact that hypertension is the most common complication of end-stage kidney disease, no evidence-based blood pressure (BP) targets exist for hemodialysis patients. There is growing evidence that outcomes are better predicted by out-of-office BP values, such as home or ambulatory BP monitoring. Intradialytic hypertension is associated with increased risk of death or hospitalization, and is probably mediated by volume overload. BP management should focus on volume control: dry weight 'probing' is well tolerated and effective in lowering BP, as are other strategies that minimize expansion of the extracellular fluid volume, such as avoidance of hypernatric dialysate. We discuss each of these issues in our review.

SUMMARY

Modest advances in the understanding of hypertension have occurred in the past 2 years. Clinical trials that focus on BP targets and treatment choices are essential to guide future practice.

Management of hypertension in hemodialysis patients

Hypertension is very common in patients with chronic kidney disease and is present in most patients with end-stage renal disease (ESRD). Hypertension is largely responsible for premature cardiovascular disease in dialysis patients. The pathophysiology of hypertension in ESRD is complex, and multiple mechanisms are likely involved in blood pressure dysregulation in patients on hemodialysis. Some of these patients demonstrate resistant hypertension. Aggressive control of hypertension in ESRD/dialysis is mandatory. Generally, nonpharmacologic treatments are not enough to achieve the goal blood pressure levels in dialysis patients. Multiple antihypertensive drugs are often necessary. Drugs that block the renin-angiotensin system offer a number of advantages for patients with chronic kidney disease or ESRD, but additional drug classes are often needed to achieve effective blood pressure control in dialysis patients. Physicians treating hypertension in dialysis patients should be familiar with the pharmacokinetic properties of antihypertensive drugs in renal failure and choose the dosages accordingly. Vigorous control of hypertension is recommended to reduce the disease burden in patients with ESRD.

Is the inverse relation between blood pressure and mortality normalized in 'low-risk' dialysis patients?

BACKGROUND

SBP is a potent predictor of mortality. However, in hemodialysis populations, the relation between SBP and mortality is a matter of debate. In hemodialysis patients, low SBP rather than high SBP has been related to mortality. It has been suggested that this inverse relationship is 'normalized' in dialysis patients with a low mortality risk and that short-term and long-term effects of SBP might differ.

DESIGN

We analyzed the relationship of mortality and SBP in 1111 incident hemodialysis patients participating in the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) cohort. Long-term and short-term effects were studied in patients with (n = 452) and without (n = 659) cardiovascular comorbidity.

RESULTS

Maximal follow-up was 7.5 years; 477 patients died. Two-year mortality rate was 44 and 20% in the groups with and without cardiovascular comorbidity, respectively. Both in the whole group and in both subpopulations, low SBP was associated with an increased mortality. The increased mortality risk associated with low SBP was especially observed as a short-term effect (6 months). In neither group did we observe a significant long-term effect between SBP and mortality.

CONCLUSION

Our data do not support the hypothesis that the inverse relation between SBP and mortality is 'normalized' in a dialysis population with a low absolute mortality risk. Neither do our data support the hypothesis that elevated SBP increases mortality risk in the long-term.

Antihypertensive agents in hemodialysis patients: a current perspective

Hypertension affects most hemodialysis patients and is often poorly controlled. Adequate control of blood pressure is difficult with conventional hemodialysis alone but is important to improve cardiovascular outcomes. Nonpharmacologic interventions to improve blood pressure include educating patients about limiting sodium intake, ensuring adequate sodium solute removal during hemodialysis, and achieving target "dry weight." However, most patients require a number of antihypertensive medications to achieve an appropriate blood pressure. First-line antihypertensive agents include angiotensin converting enzyme inhibitors and angiotensin receptor blockers given their safety profile and demonstrated benefit on cardiovascular outcomes in clinical trials. beta-blockers and combined alpha- and beta-blockers should also be used in patients with cardiovascular disease or congestive heart failure and may improve outcomes in these populations. Calcium channel blockers and direct vasodilators are also effective for controlling blood pressure. Many blood pressure agents can be dosed once daily and should preferentially be administered at night to control nocturnal blood pressure and minimize intradialytic hypotension. In patients who are noncompliant with therapy, renally eliminated agents (such as lisinopril and atenolol) can be given thrice weekly following hemodialysis. Older antihypertensive agents which require thrice daily dosing ought to be avoided given the high pill burden with these regimens and the concern for noncompliance resulting in rebound hypertension. Newer antihypertensive agents, such as direct renin inhibitors, may provide alternative options to improve blood pressure but require testing for efficacy and safety in hemodialysis patients.

Effect of amlodipine on cardiovascular events in hypertensive haemodialysis patients

BACKGROUND

Hypertensive haemodialysis patients may be at a high risk for cardiovascular events. This study was undertaken to ascertain whether the calcium channel blocker amlodipine reduces mortality and cardiovascular events in these high-risk patients.

METHODS

We evaluated the effects of amlodipine on cardiovascular events in 251 hypertensive haemodialysis patients in an investigator-designed, prospective, randomized, double-blind, placebo-controlled, multicenter trial. One hundred and twenty-three patients were randomly assigned to amlodipine (10 mg once daily) and 128 to placebo. The primary endpoint was mortality from any cause. The secondary endpoint was a composite variable consisting of mortality from any cause or cardiovascular event. Analysis was by intention-to-treat. The trial was registered with ClinicalTrials.gov (number NCT00124969).

RESULTS

The median age of patients was 61 years (25% percentile - 75% percentile, 47-69), and the median follow-up was 19 months (8-30). Fifteen (12%) of the 123 patients assigned to amlodipine and 22 (17%) of the 128 patients assigned to placebo had a primary endpoint [hazard ratio 0.65 (95% CI 0.34-1.23); P = 0.19]. Nineteen (15%) of the 123 haemodialysis patients assigned to amlodipine and 32 (25%) of the 128 haemodialysis patients assigned to placebo reached the secondary composite endpoint [hazard ratio 0.53 (95% CI 0.31-0.93); P = 0.03].

CONCLUSION

Amlodipine safely reduces systolic blood pressure and it may have a beneficial effect on cardiovascular outcomes in hypertensive haemodialysis patients.

Predictors of survival after cardiac arrest in outpatient hemodialysis clinics

Cardiac arrest (CA) is the most common cause of death in hemodialysis patients, and factors that improve survival after arrest are unknown. This study sought to identify modifiable factors that are associated with survival after CA in hemodialysis clinics. Patients who experienced in-center CA in the Gambro Healthcare System in the United States from 2002 to 2005 were identified. Patient characteristics at the time of arrest were compared between survivors and nonsurvivors at 24 h and 6 mo after CA. A total of 729 patients sustained in-clinic CA; 310 (42.5%) patients survived 24 h, and 80 (11%) patients survived 6 mo. Traditional risk factors, including cardiovascular comorbidities, diabetes, hemoglobin, and dialysis adequacy, did not predict survival at either time point. After adjustment for case-mix factors, presence of indwelling catheter, and concomitant medications, only use of beta blockers (BBL), calcium-channel blockers (CCB), and angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) remained significantly associated with survival (BBL odds ratio [OR] 0.32 [95% confidence interval (CI) 0.17 to 0.61]; CCB OR 0.42 [95% CI 0.23 to 0.76]; ACEI/ARB OR 0.51 [95% CI 0.28 to 0.95]). The beneficial effect of ACEI/ARB and BBL on survival increased sequentially with higher medication dosages. Prescription of BBL at the time of the event was the only predictive variable of survival at 24 h. Therefore, traditional cardiovascular risk factors were not associated with survival after CA in this hemodialysis cohort. The benefits that are associated with BBL, CCB, and ACEI/ARB suggest that these medications may improve the chances of survival after CA.

Clearance of Imidapril, an Angiotensin-Converting Enzyme Inhibitor, During Hemodialysis in Hypertensive Renal Failure Patients: Comparison With Quinapril and Enalapril

The dialyzability of imidaprilat, an active metabolite of the angiotensin-converting enzyme (ACE) inhibitor imidapril, was determined and compared with those of enalaprilat and quinaprilat in hypertensive patients on chronic hemodialysis. Imidapril (5 mg/d, n = 6), enalapril (2.5 mg/d, n = 6), or quinapril (2.5 mg/d, n = 6) was given for at least 8 weeks prior to the trial. During dialysis, enalaprilat, but not imidaprilat or quinaprilat, concentrations in both sides decreased significantly. Compared to enalaprilat, the dialyzabilities of imidaprilat and quinaprilat were significantly lower (dialyzer clearance [mL/min/m(2)]: enalaprilat, 41.8 +/- 7.4; imidaprilat, 19.0 +/- 7.8; quinaprilat, 8.9 +/- 1.3). The dialyzabilities of the 3 drugs were negatively correlated with their respective protein-binding rates. During hemodialysis, blood pressure did not change significantly in any group. These results suggest that imidapril provides good blood pressure control without a large fluctuation of drug concentration in hypertensive patients undergoing chronic hemodialysis.

Calcium channel blockers in the spectrum of antihypertensive agents

Calcium channel blockers (CCBs) are widely used in the treatment of hypertension. Through blood pressure reduction, and possibly other mechanisms such as antioxidative effects, they may play a role in diminishing the risk for a variety of cardiovascular outcomes. The combination of CCBs with other newer antihypertensive agents such, as ACE inhibitors and angiotensin receptor blockers, may provide complementary effects on risk reduction in cardiovascular adverse events and renal disease. Although the efficacy of CCBs as antihypertensive agents has been adequately demonstrated, there have been concerns regarding the use of short acting dihydropyridines after acute myocardial infarction. There have also been questions about the role of CCBs with regards to other antihypertensive agents in renal disease. For example, differential effects of dihydropyridine and non-dihydropyridine CCBs may affect progression of renal disease and risk for diabetes. Certain precautions involving drug interactions are needed because of the effects of CCBs on the CYP450 enzyme systems.

Current understanding of optimal blood pressure goals in dialysis patients

The hemodialysis population is associated with a very low survival rate, with myocardial infarctions and strokes accounting for most of the increased mortality. Recent observational studies demonstrate a paradoxical relationship between increasing blood pressure and increasing mortality. Hypertension treated with antihypertensive medications unequivocally reduces cerebrovascular risk, but demonstration of a survival benefit for cardiovascular mortality has proven more difficult to demonstrate. Increased pulse pressure is caused by inadequate dialysis treatment that increases arterial wall stiffness and afterload, and decreases coronary perfusion. The disproportionate representation of diastolic dysfunction and coronary artery atherosclerosis may explain why increased pulse pressure is associated with higher cardiovascular risk for the dialysis population. Optimum blood pressure control has not been established, due to a lack of prospective studies targeting blood pressure reduction. Opinion-based recommendations are offered, but goals should be individualized based on a complete assessment of prevailing comorbidities and should target normalization of the pulse pressure.

Verapamil and mild hyperkalemia in hemodialysis patients: A potentially hazardous association

During the past 3 years, 3 patients undergoing intermittent hemodialysis (or about to do so) in our hospital developed a third-degree atrioventricular block while being treated with verapamil for blood pressure or supraventricular arrhythmia. In the 3 cases, mild hyperkalemia was concomitant. The medical history of these patients revealed no intrinsic cause of atrioventricular conduction disturbance. We report herein the 3 cases and draw attention to the risks of atrioventricular block in this particular context.

Coronary artery disease and peripheral vascular disease in chronic kidney disease: an epidemiological perspective

The enormous burden of CAD and PVD inpatients who have CKD contributes substantially to increased morbidity and mortality. The increased risk of vascular disease observed in CKD patients is likely to be multifactorial, with contributions from traditional and nontraditional cardiovascular factors. Given the overwhelming evidence on the known benefits of cardioprotective medications, their underuse remains puzzling in a population at enormous risk. During the past 5 years, the research community and national interest groups have made significant progress in organizing a concerted approach to improve the management of patients who have CKD and vascular disease. Much work remains to be done. The development of national guidelines in the management of these patients at high risk for future cardiovascular events will be a welcome step. The evaluation of multitargeted interventions for reduction of cardiovascular risk through randomized clinical trials is desperately needed. Finally, the low use of known cardioprotective strategies in this high-risk group is a serious issue and warrants immediate attention at local and national levels.