Dialysis Modality and Incident Atrial Fibrillation in Older Patients With ESRD

New Insights on Cardiac Arrhythmias in Patients With Kidney Disease

The risk of arrhythmia and its management become increasingly complex as kidney disease progresses. This presents a multifaceted clinical challenge. Our discussion addresses these specific challenges relevant to patients as their kidney disease advances. We highlight numerous opportunities for enhancing the current standard of care within this realm. Additionally, this review delves into research concerning early detection, prevention, diagnosis, and treatment of various arrhythmias spanning the spectrum of kidney disease.

Dialysis Modality, Transplant Characteristics, and Incident Atrial Fibrillation After Kidney Transplant: An Observational Study Using USRDS Data

Rationale & Objective

Atrial fibrillation is the most common arrhythmia and is increasing in prevalence. The prevalence of atrial fibrillation is high among patients receiving dialysis, affecting ∼21.3% of the patients receiving hemodialysis and 15.5% of those receiving peritoneal dialysis. The association of previous dialysis modality with incident atrial fibrillation in patients after receiving their first kidney transplant has not been studied.

Study Design

We used the United States Renal Data System to retrospectively identify adult, Medicare-insured patients who received their first kidney transplant between January 1, 2005, and September 30, 2012 and who had not previously been diagnosed with atrial fibrillation.

Setting & Participants

The study included 43,621 patients who were aged 18 years older when receiving a first kidney transplant between January 1, 2005, and September 30, 2012 and whose primary payer was Medicare (parts A and B) at the time of transplantation and the 6 months preceding it.

Exposure

Dialysis modality used before transplant.

Outcome

Time to incidence of atrial fibrillation up to 3 years posttransplant.

Analytical Approach

Multivariable Cox regression was used to estimate HRs.

Results

Of 43,621 patients, 84.9% received hemodialysis and 15.1% received peritoneal dialysis before transplant. The mean ± SD age was 51 ± 13.6 years; 60.8% were male, 55.6% White, and 35.8% Black race. The mean dialysis vintage was 4.3 ± 2.8 years. Newly diagnosed atrial fibrillation after kidney transplant occurred in 286 patients (during 15,363 person-years) who had received peritoneal dialysis and in 2,315 patients (during 83,536 person-years) who had received hemodialysis. After multivariable adjustment, atrial fibrillation was 20% (95% CI, 4%-38%) more likely in those who had been receiving hemodialysis versus peritoneal dialysis, regardless of whether death was considered a competing risk or a censoring event. Each year of pretransplant dialysis vintage increased the risk of posttransplant atrial fibrillation by 6% (95% CI, 3%-9%).

Limitations

Residual confounding; data from billing claims does not specify the duration of atrial fibrillation or whether it is valvular.

Conclusions

Pretransplant hemodialysis, as compared with peritoneal dialysis, was associated with higher risk of newly diagnosed atrial fibrillation after a first kidney transplant.

Plain-Language Summary

New-onset atrial fibrillation (AF) occurs in 7% of kidney transplant recipients in the first 3 years posttransplantation. We conducted this study to determine whether pretransplant dialysis modality was associated with posttransplant AF. We identified 43,621 patients; 84.9% used hemodialysis and 15.1% used peritoneal dialysis pretransplant. Multivariable Cox regression was used to estimate hazard ratios. We found that patients receiving hemodialysis pretransplant were at 20% increased risk of developing posttransplant AF as compared with patients receiving peritoneal dialysis. As our understanding of transplant-specific risk factors for AF increases, we may be able to better risk-stratify transplant patients and develop monitoring and management strategies that can improve outcomes.

Clinical outcomes between elderly ESKD patients under peritoneal dialysis and hemodialysis: a national cohort study

With ageing populations, new elderly end-stage kidney disease (ESKD) cases rise. Unlike younger patients, elderly ESKD patients are less likely to undergo kidney transplant, and therefore the decision of receiving peritoneal dialysis (PD) and hemodialysis (HD) is more crucial. A total of 36,852 patients, aged more than 65, who were newly diagnosed with ESKD and initiated renal replacement therapy between 2013 and 2019 were identified. These patients were categorized into two groups: the PD group and the HD group according to their long-term renal replacement treatment. After propensity score matching, the PD group (n = 1628) displayed a lower incidence of major adverse cardiac and cerebrovascular events (MACCE) (10.09% vs. 13.03%, hazard ratio (HR): 0.74, 95% confidence interval (CI): 0.66-0.83), malignancy (1.23% vs. 2.14%, HR: 0.55, 95% CI: 0.40-0.76), and MACCE-associated mortality (1.35% vs. 2.25%, HR: 0.62, 95% CI: 0.46-0.84) compared to the HD group (n = 6512). However, the PD group demonstrated a higher rate of infection (34.09% vs. 24.14%, HR: 1.28, 95% CI: 1.20-1.37). The risks of all-cause mortality and infection-associated mortality were not different. This study may provide valuable clinical information to assist elderly ESKD patients to choose HD or PD as their renal replacement therapy.

Atrial Fibrillation in Kidney Failure: Challenges in Risk Assessment and Anticoagulation Management

Management of atrial fibrillation (AF) is a clinical conundrum in people with kidney failure. Stroke risk is disproportionately high, but clinicians have a limited armamentarium to improve outcomes in this population in whom there is a concurrently high bleeding risk. Direct oral anticoagulants may have a superior benefit-risk profile compared with vitamin K antagonists in people on hemodialysis. Although research has predominantly focused on identifying a safe and effective oral anticoagulation option to reduce stroke risk in people with kidney failure (and predominantly those on hemodialysis), it remains uncertain how clinicians discriminate between people who would derive net clinical benefit as opposed to net harm. The recommended CHA2DS2-VASc score cutoffs provide poor discriminatory value, and there is an urgent need to identify robust markers of thromboembolic risk in kidney failure. There is increasing data to challenge the prior dogma of risk equivalence across AF type, and the American Heart Association highlights moving beyond AF as a binary entity to consider the prognostic significance of AF burden. Implantable cardiac monitor studies reveal high rates and varied burden of subclinical and paroxysmal AF in people on hemodialysis. The association between AF burden and the proarrhythmic environment of hemodialysis with cyclical volume loading, offloading, and electrolyte changes is not well studied. We review the significance of AF burden as a contributor to thromboembolic risk, its potential as the missing link in risk assessment, and updated evidence for anticoagulation in people with kidney failure.

Implantable Loop Recorder Monitoring and the Incidence of Previously Unrecognized Atrial Fibrillation in Patients on Hemodialysis

INTRODUCTION

Atrial fibrillation (AF) is common in patients with kidney failure on hemodialysis (KF-HD). We determined both AF incidence and burden in patients with KF-HD using implantable loop recorder (ILR) monitoring.

METHODS

Patients with KF-HD were enrolled and received an ILR. In 6 monitoring months, the incidence of AF events lasting ≥6 minutes was captured. Demographic, clinical, and dialysis characteristics were collected, and associations with incident AF were estimated using negative binomial regression models and expressed as incidence rate ratios and 95% CIs.

RESULTS

We enrolled 66 patients with KF-HD (mean age = 56 years, 70% male); 59 (90%) were without previously diagnosed AF. AF lasting ≥6 minutes was detected in 18 of 59 subjects (31%) without previously diagnosed AF and in 5 of 7 subjects (71%) with a previous AF diagnosis. Among the 23 with detected AF, episodes were present on 16% of patient days. Although 14 of 23 patients (61%) had AF on <5% of monitored days, the average duration of AF episodes was <1 hour in 13 of 23 patients (52%). Among patients with AF ≥6 minutes, 19 of 23 (83%) had a CHA2DS2-VASc score ≥2. When investigating individual HD parameters, higher dialysate calcium (>2.5 vs. 2.5 mEq/l: incidence rate ratio = 0.62; 95% CI, 0.48-0.80) was associated with lower AF risk whereas higher dialysate bicarbonate concentrations (>35 vs. 35 mEq/l: incidence rate ratio = 3.18; 95% CI, 1.13-8.94) were associated with higher AF risk.

CONCLUSION

New AF was detected in approximately one-third of patients with KF-HD. AF affects a substantial proportion of patient days and may be an underappreciated cause of stroke in KF-HD.

Ultrafiltration rate and incident atrial fibrillation among older individuals initiating hemodialysis

BACKGROUND

Higher ultrafiltration (UF) rates are associated with numerous adverse cardiovascular outcomes among individuals receiving maintenance hemodialysis. We undertook this study to investigate the association of UF rate and incident atrial fibrillation in a large, nationally representative US cohort of incident, older hemodialysis patients.

METHODS

We used the US Renal Data System linked to the records of a large dialysis provider to identify individuals ≥67 years of age initiating hemodialysis between January 2006 and December 2011. We applied an extended Cox model as a function of a time-varying exposure to compute adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of delivered UF rate and incident atrial fibrillation.

RESULTS

Among the 15 414 individuals included in the study, 3177 developed atrial fibrillation. In fully adjusted models, a UF rate >13 mL/h/kg (versus ≤13 mL/h/kg) was associated with a higher hazard of incident atrial fibrillation [adjusted HR 1.19 (95% CI 1.07-1.30)]. Analyses using lower UF rate thresholds (≤10 versus >10 mL/h/kg and ≤8 versus >8 mL/h/kg, separately) yielded similar results. Analyses specifying the UF rate as a cubic spline (per 1 mL/h/kg) confirmed an approximately linear dose-response relationship between the UF rate and the risk of incident atrial fibrillation: risk began at UF rates of ~6 mL/h/kg and the magnitude of this risk flattened, but remained elevated, at rates ≥9 mL/h/kg.

CONCLUSION

In this observational study of older individuals initiating hemodialysis, higher UF rates were associated with higher incidences of atrial fibrillation.

A Comparison of Hemodialysis and Peritoneal Dialysis in Patients with Cardiovascular Disease

The high prevalence of cardiovascular disease is caused by the traditional cardiovascular risk factors common among end-stage renal disease patients, and nontraditional risk factors attributed to underlying kidney disease, including chronic inflammation, anemia, bone mineral disease, and the dialysis procedure itself. Individualization of the treatment of cardiovascular disease in end-stage renal disease that could impact the underlying mechanisms of the cardiovascular diseases is important to improve outcomes. This article reviews and compares hemodialysis and peritoneal dialysis in association with different cardiovascular diseases affecting dialysis patients, including hypertension, coronary artery disease, myocardial stunning, cardiac arrhythmias, heart failure, and the cardiorenal syndrome.

Dialysis Mode and Associated Outcomes in Patients With End-Stage Renal Disease and Atrial Fibrillation: A 14-Year Nationwide Cohort Study

Background Benefits of patients with end-stage renal disease and atrial fibrillation undergoing peritoneal dialysis (PD) or hemodialysis are unknown. Methods and Results Patients undergoing dialysis were retrieved from Taiwan National Health Insurance Research Database during 2001 to 2013 and separated into PD or hemodialysis. Primary outcomes were ischemic stroke/systemic embolism, major bleeding, and intracranial hemorrhage (ICH). An inverse probability of treatment weighting based on propensity score was used to reduce the confounding. The risk of outcomes between PD and hemodialysis was compared using Cox proportional hazard model for fatal outcomes or Fine and Gray subdistribution hazard model which considered death a competing risk, respectively. A total of 7916 patients with end-stage renal disease with atrial fibrillation undergoing PD or hemodialysis during 2001 to 2013 were identified. After exclusion criteria, 363 patients receiving PD and 5302 patients receiving hemodialysis were analyzed. At 1-year follow-up, the risk of ICH was significantly lower in the PD group compared with the hemodialysis group (0.2% versus 0.9%; subdistribution hazard ratio [SHR], 0.31; 95% CI, 0.17-0.57). At 3-year follow-up, the risks of major bleeding and ICH were significantly lower in the PD group compared with the hemodialysis group (major bleeding: 1.8% versus 3.2%; SHR, 0.68; 95% CI, 0.53-0.87; ICH: 0.5% versus 2%; SHR, 0.32; 95% CI, 0.21-0.48). At 5-year follow-up, ischemic stroke/systemic embolism, major bleeding, and ICH were significantly lower in the PD group compared with the hemodialysis group (ischemic stroke/systemic embolism: 12.4% versus 17.7%, SHR, 0.87; 95% CI, 0.79-0.96; major bleeding: 2.6% versus 4.1%; SHR, 0.79; 95% CI, 0.64-0.97; ICH: 0.5% versus 2.6%; SHR, 0.25; 95% CI, 0.17-0.37). Conclusions In patients with end-stage renal disease and atrial fibrillation, dialytic modalities by PD or hemodialysis impacted these patients differently. There were overall reduced ischemic stroke/systemic embolism, major bleeding, and ICH at 5-year follow-up in patients undergoing PD compared with hemodialysis.

Oral anticoagulation in chronic kidney disease with atrial fibrillation

Chronic kidney disease (CKD) and atrial fibrillation (AF) frequently coexist, amplifying the risk of cardiovascular events and mortality. In patients with CKD stage 3 and non-valvular AF, direct oral anticoagulants (DOACs) have shown, compared to vitamin K antagonists (VKA), equal or greater efficacy in the prevention of stroke and systemic embolism, and greater safety. There are no randomizedtrials of the efficacy and safety of DOACs and VKA in advanced CKD. On the other hand, observational studies suggest that DOACs, compared to warfarin, are associated with a lower risk of acute kidney damage and generation/progression of CKD. This paper reviews the epidemiological and pathophysiological aspects of the CKD and AF association, the evidence of the efficacy and safety of warfarin and ACODs in various stages of CKD with AF as well as the comparison between warfarin and ACODs in efficacy and anticoagulant safety, and in its renal effects.

New-onset atrial fibrillation in patients with acute kidney injury on continuous renal replacement therapy

PURPOSE

The mortality of critically ill patients with acute kidney injury (AKI) who require continuous renal replacement therapy (CRRT) remains high. We assessed the incidence and predictors of new-onset atrial fibrillation (NOAF) in this population and its impact on outcomes.

MATERIALS AND METHODS

This is a retrospective cohort study of adult intensive care units (ICU) patients who had AKI and received CRRT from December 2006 through November 2015 in a tertiary academic medical center. Cox proportional hazard model was used to evaluate the impact of NOAF on overall mortality.

RESULTS

Out of 1398 screened patients, NOAF occurred in 193 (14%) cases. NOAF occurring on CRRT was independently associated with an increased hazard of death at follow-up (HR: 1.26; 95% CI: 1.03-1.56), compared to the group who did not have NOAF. In the multivariable analysis using time-dependent covariates, higher potassium (HR 1.24, 95%CI: 1.01-1.54) and bicarbonate (HR 0.95, 95%CI: 0.92-0.98) levels were associated with increased and decreased risk of NOAF on CRRT, respectively.

CONCLUSIONS

NOAF in critically ill patients with AKI receiving CRRT is common and carries an unfavorable prognosis. Prospective studies are required to elucidate modifiable risk factors for NOAF occurring on CRRT.

Comparison of cardiovascular mortality in hemodialysis versus peritoneal dialysis

PURPOSE

Cardiovascular disease is a significant cause of morbidity and mortality in dialysis patients. With the increasing prevalence of dialysis patients, there is a need to systematically identify the epidemiology of cardiovascular disease in hemodialysis and peritoneal dialysis patients.

METHODS

A meta-analysis was conducted in reference to the MOOSE and PRISMA guidelines. Database searches were conducted on Medline and Embase on 17 March 2020. Meta-analysis of proportions was used to summarize the overall prevalence of events. Pairwise comparisons were used to compare between hemodialysis and peritoneal dialysis, and meta-regression was applied to identify the factors influencing disease.

RESULTS

A total of 28 studies were included in the review and prevalence of cardiovascular disease events including coronary artery disease, coronary artery complications, congestive heart failure, peripheral arterial disease, atrial fibrillation, and cardiovascular mortality were summarized. Atrial fibrillation (RR 1.287 CI 1.154-1.436, p < 0.001), congestive heart failure (RR 1.229 CI 1.074-1.407, p = 0.003), and peripheral arterial disease (RR 1.132 CI 1.021-1.255, p = 0.019) were more common in hemodialysis patients, but cardiovascular mortality was lower in hemodialysis relative to peritoneal dialysis patients. (RR 0.892 CI 0.828-0.960, p = 0.002).

CONCLUSION

The authors have found fewer cardiovascular events but higher cardiovascular mortality in patients on PD as compared to those on HD. Future research is required to establish the causality between dialysis modality and the cardiovascular outcomes described.

Aortic stenosis in patients with kidney failure: Is there an advantage for a PD-first policy?

Aortic stenosis (AS) is the most common valvular disease. It is twice as prevalent in patients with kidney failure as compared to the general population. In addition, AS progresses at a faster rate and is associated with a higher risk of death and poorer quality of life in patients on dialysis. Chronic kidney disease–mineral and bone disorder (CKD-MBD), inflammation, and hemodynamic disturbances contribute to the pathophysiology and progression of AS. Whether the type of dialysis modality, that is, hemodialysis (HD) versus peritoneal dialysis (PD), has a differential impact on the development and progression of AS in patients with kidney failure remains debated. Recent data indicate that the prevalence of valvular calcifications might be lower and the development of AS delayed in PD patients, as compared to those treated with HD. This could be accounted for by several mechanisms including reduced valvular shear stress, better preservation of residual kidney function (with better removal of protein-bound uremic toxins and CKD-MBD profile), and lower levels of systemic inflammation. Given the high morbidity and mortality rates related to interventional procedures in the population with kidney failure, surgical and transcatheter aortic valve replacement should be considered in selected patients with severe AS. Strategies slowing down the progression of aortic valve remodeling should remain the cornerstone in the management of individuals with kidney failure and mild to moderate AS. This review explores the potential benefits of PD in patients with kidney failure and AS and provides some clues to help clinicians in the decision-making process when options for kidney replacement therapy are considered in patients with AS.

Factors associated with renal impairment in Chinese patients with non-valvular AF and without an established renal disease: a cross-sectional study

BACKGROUND

Renal impairment and atrial fibrillation (AF) often coexist. However, risk factors associated with renal impairment in AF patients have not been studied in a large population. Accordingly, this study investigated clinical factors associated with renal impairment in AF patients.

METHODS

From January 2012 to December 2016, 2,298 inpatients with non-valvular AF (NVAF) mainly for catheter ablation were enrolled in this cross-sectional study. Data collection included past medical history, echocardiography measurements, current medicine use and biochemical results. The estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Renal impairment was defined as a history of chronic kidney disease or an eGFR ≤90 ml/min/1.73 m². Multivariate logistic regression was conducted to evaluate the relationship between the factors screened and eGFR.

RESULTS

The mean eGFR was 88.6 ± 17.1 ml/min/1.73 m². The overall prevalence of renal impairment was 47.4%. Multivariate logistic regression showed that factors associated with renal impairment were age (OR: 1.12; 95% CI: 1.11-1.14), non-paroxysmal AF (OR: 1.28; 95% CI: 1.04-1.58), use of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) (OR: 1.58; 95% CI: 1.28-1.95), congestive heart failure (OR: 1.80; 95% CI: 1.05-3.07), left ventricular ejection fraction (LVEF) <50% (OR: 2.39; 95% CI: 1.34-4.28), and prior transient ischemic attack (TIA)/stroke/systematic embolism (SE) (OR: 2.69; 95% CI: 1.68-4.29).

CONCLUSIONS

Renal dysfunction is highly prevalent in Chinese NVAF patients and is significantly associated with older age, non-paroxysmal AF, use of ACEI/ARB, congestive heart failure, LVEF <50% and prior TIA/stroke/SE. Further studies on the mechanisms by which these risk factors affect renal function in NVAF patients need to be conducted.

Atrial fibrillation and associated outcomes in patients with peritoneal dialysis and hemodialysis: a 14-year nationwide population-based study

BACKGROUND

Patients with end-stage renal disease (ESRD) undergoing dialysis have increased risks of atrial fibrillation (AF).

OBJECTIVE

To investigate dialysis-related incident AF and associated outcomes.

METHODS

Patients with dialysis were retrieved using data from Taiwan National Health Insurance Research Database during 2001-2013. Patients were separated into peritoneal dialysis (PD) and hemodialysis (HD) according to their initial modality. Primary outcome was new-onset AF. Secondary outcomes were AF-associated ischemic stroke (IS)/systemic embolism (SE) and hemorrhagic stroke.

RESULTS

A total of 158,910 dialytic patients were retrieved. After exclusion criteria, a total of 117,023 patients with ESRD undergoing dialysis were separated into 12,659 patients on PD and 104,364 patients on HD. There were 458 PD patients with subsequent development of AF, and 6216 HD patients with subsequent development of AF. At end of follow-up, patients on PD and HD had AF incidence densities of 7.8 and 8.8 events per 1000 person-years, the SHR of PD versus HD was 0.83 (95% CI 0.73-0.94). The SHR of PD versus HD was 1.07 (95% CI 0.80-1.44) for IS/SE and the SHR of PD versus HD was 0.34 (95% CI 0.13-0.90) for hemorrhagic stroke.

CONCLUSION

In patients with ESRD undergoing dialysis, PD had lowered risks of new onset of AF compared to HD. Subsequently, these AF patients in PD group had comparable incidence of ischemic stroke but decreased incidence of hemorrhagic stroke compared to AF patients in HD group. PD could be the most suitable modality in patients at risk for the onset of AF.

[Atrial Fibrillation in Patients on Dialysis Therapy: Epidemiology, Prognosis and Choice of Anticoagulant Therapy]

The review presents data on the prevalence of atrial fibrillation in patients on dialysis therapy. It is shown that dialysis-dependent patients with non-valve atrial fibrillation prognosis is extremely unfavorable, significantly increased risk of death due to both ischemic and hemorrhagic complications. Scales to assess the risk of thromboembolic and hemorrhagic complications in patients with atrial fibrillation on program dialysis are not validated. The lack of data from randomized clinical trials makes it much more difficult to choose anticoagulant therapy in patients with terminal stage of chronic kidney disease on dialysis who have undergone kidney transplantation. Therefore, the need for anticoagulant therapy and the choice of drugs in patients in this category should be made on the basis of a personalized multidisciplinary approach, taking into account comorbid pathology and the patient's preferences.

Cardiovascular Outcomes of Calcium-Free vs Calcium-Based Phosphate Binders in Patients 65 Years or Older With End-stage Renal Disease Requiring Hemodialysis

IMPORTANCE

Guidelines restricting use of calcium-based phosphate binders in all patients with end-stage renal disease owing to their potential contribution to increased cardiovascular risk shifted prescribing from calcium acetate toward the costlier sevelamer carbonate products.

OBJECTIVE

To compare cardiovascular events and mortality between patients with end-stage renal disease (ESRD) undergoing hemodialysis receiving sevelamer vs calcium acetate in real-world practice.

DESIGN, SETTING, AND PARTICIPANTS

An observational cohort study was conducted using the United States Renal Data System linked to Medicare claims data (May 1, 2012, to December 31, 2013). Data analysis was performed from October 2017 to September 2018. Participants included patients 65 years or older with ESRD within 180 days after starting hemodialysis (sevelamer, 2647; calcium acetate, 2074).

EXPOSURES

New use of sevelamer (calcium-free phosphate binder) vs calcium acetate (calcium-based phosphate binder).

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) with 95% CIs were estimated for fatal or nonfatal cardiovascular events (myocardial infarction or ischemic stroke: primary outcome) and all-cause mortality (secondary outcome) using Cox proportional hazards regression with fine stratification on the propensity score to control for potential confounders, including phosphorus and calcium levels.

RESULTS

After propensity score weighting, 2639 patients initiating sevelamer treatment (1184 men [44.9%]; mean [SD] age, 75.6 [6.9] years) and 2065 patients initiating calcium acetate treatment (930 men [45.0%]; mean [SD] age, 75.5 [7.1] years) were included in the analysis. Crude incidence rates (IRs) for cardiovascular events of 458 per 1000 person-years for sevelamer and 464 per 1000 person-years for calcium acetate were observed. After propensity score fine-stratification weighting, HRs of 0.96 (95% CI, 0.84-1.10) for cardiovascular events were observed. Results were consistent within subgroups of age (<75 y: primary outcome, HR, 1.02; 95% CI, 0.85-1.24; vs ≥75 years: primary outcome, HR, 0.83; 95% CI, 0.69-1.01) and sex (primary outcome in men: HR, 1.02; 95% CI, 0.83-1.26).

CONCLUSIONS AND RELEVANCE

The results of the study do not suggest increased cardiovascular safety of sevelamer in the routine clinical practice of patients with ESRD compared with calcium acetate; this study's findings suggest that well-designed, long-term, randomized clinical trials are needed.