Nephrology News

Body Mass Index-Mortality Paradox in Hemodialysis Patients
In the general population, there is a clear association between body mass index (BMI) and mortality. However, in hemodialysis patients, a number of clinical studies have demonstrated that BMI is inversely related to mortality. The explanation for this interesting paradox is unknown.

Mortality Benefit Seen with Home Dialysis
There is a resurgence of interest in home hemodialysis (HD), especially frequent or extended forms involving unconventionally frequent (>3 times/wk) and/or long (>6 hours) treatments. This resurgence is driven by cost containment and experience suggesting lower mortality risk compared with facility HD and peritoneal dialysis (PD). The authors performed an observational cohort study using the Australia and New Zealand Dialysis and Transplant Registry.This study supports a survival advantage of home HD without a difference between conventional and frequent/extended modalities. Suitably designed clinical trials of frequent/extended HD are needed to determine the presence and extent of mortality benefit with this modality.

Low 25-Hydroxyvitamin D Levels and Mortality in Non–Dialysis-Dependent CKD
Low 25-hydroxyvitamin D (25[OH]D) levels are common in patients with non–dialysis-dependent chronic kidney disease (CKD). The associations between low 25(OH)D levels and mortality in non–dialysis-dependent patients with CKD are unclear. This was a Retrospective cohort study of Patients with stages 3-4 CKD (estimated glomerular filtration rate, 15-59 mL/min/1.73 m2; n = 12,673) who had 25(OH)D levels measured after the diagnosis of CKD in the Cleveland Clinic Health System. Of 12,763 patients with CKD, 15% (n = 1,970) had 25(OH)D levels <15 ng/mL, whereas 45% (n = 5,749) had 25(OH)D levels of 15-29 ng/mL. After covariate adjustment, patients with CKD with 25(OH)D levels <15 ng/mL had a 33% increased risk of mortality (95% CI, 1.07-1.65). The group with 25(OH)D levels of 15-29 ng/mL did not show a significantly increased risk of mortality (HR, 1.03; 95% CI, 0.86-1.22) compared with patients with 25(OH)D levels ≥30 ng/mL.

Serum Albumin and Mortality in PD 
Over the years, the US Centers for Medicare & Medicaid Services has launched initiatives to monitor the quality of care in dialysis units. Serum albumin has been a key measure included in some of these initiatives. Low serum albumin is associated with increased mortality in dialysis patients and may represent a simple measure of their health status. In part reflecting albumin loss with PD, the level of serum albumin for which mortality risk increases for PD patients may differ from that in HD patients. In this issue, Mehrotra et al conclude that serum albumin levels differ by dialysis modality, with increased mortality risk not seen until lower serum albumin threshold in PD versus HD. They suggest that this difference should be considered by agencies and organizations when setting quality of care standards.

ACEI use was not significantly associated with mortality or cardiovascular morbidity in patients with ESRD
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. The authors of this study conducted a secondary analysis of results of the HEMO study that 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. In this 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.

Association of Race and Age Seen With Survival Among Patients Undergoing DialysisMany studies have reported that black individuals undergoing dialysis survive longer than those who are white. This observation is paradoxical given racial disparities in access to and quality of care, and is inconsistent with observed lower survival among black patients with chronic kidney disease. The authors hypothesized that age and the competing risk of transplantation modify survival differences by race. Overall, among dialysis patients in the United States, there was a lower risk of death for black patients compared with their white counterparts. However, the commonly cited survival advantage for black dialysis patients applies only to older adults, and those younger than 50 years have a higher risk of death.

Acute Kidney Injury Worsened by the Presence of CKD
Acute kidney injury (AKI) in hospitalized patients is associated with poor outcomes; however, it is unclear how relationships between AKI and clinical outcomes vary with baseline kidney function. This was a Population-based cohort of Adults in Alberta, Canada, who were hospitalized between January 1, 2003, and December 31, 2006, with at least 1 serum creatinine measurement during hospitalization and 1 outpatient creatinine measurement within 6 months preceding admission. The authors found that AKI of any severity increases the risk of death both during hospitalization and after discharge. Although the risk of developing ESRD after AKI is greatest in patients with baseline eGFR <30 mL/min/1.73 m2, this is exceeded by the risk of death.

Acute pulmonary oedema in chronic dialysis patients admitted into an intensive care unit
Acute pulmonary oedema (APO) in patients undergoing chronic dialysis (CD), a common cause of hospital admission in this population, is poorly documented. The objective of this study was to determine the causes, profile, clinical course and outcomes of APO in CD patients admitted in an intensive care unit (ICU). Of the 112 files considered, 102 (65% men) were included in the final analysis. Patients were aged 20–88 years and had been dialysed for a median duration of 2 years. Hypertension (36.3%), chronic glomerulonephritis (25.5%) and diabetes mellitus (17.6%) were the main etiologic factors of chronic renal failure; 38.2% had a past history of APO. Acute pulmonary infection (26%), excessive interdialytic weight gain (25%) and inappropriate dry weight prescription (23%) were the leading causes of APO. The duration of hospitalization was <4 days in 60% of participants. Nine deaths (four being of cardiac origin) were recorded. Being referred from another hospital service was the main predictor of death.

Being Female an Intrinsic Risk for Contrast Nephropathy
 Being female remained an independent risk marker for radiocontrast-induced nephropathy (RCIN), especially in women with normal kidney function at baseline, even after controlling for known risk factors, according to a study presented here at the National Kidney Foundation 2011 Clinical Meetings. "Our study attempts to bring into consideration the fact that women (based on unknown gender-specific responses to contrast dye), despite having normal kidney function, should have close monitoring and adequate intravascular volume expansion with normal saline — similar to other well-defined high-risk groups — prior to coronary angiography," said study investigator Javier Neyra, MD, from the Henry Ford Hospital in Detroit, Michigan.

Long-term Follow-up of the Hemodialysis Infection Prevention With Polysporin Ointment (HIPPO) Study
Infection is a common and serious complication in hemodialysis patients accessed using central venous catheters (CVCs). Previously, a randomized double-blinded trial (HIPPO [Hemodialysis Infection Prevention With Polysporin Ointment] Study) showed that application of a topical polyantibiotic ointment at the CVC exit site decreased CVC-related infections, including bacteremias and their adverse consequences. Based on this study's results, our institution implemented a policy of routine topical polyantibiotic ointment application for CVC-related infection prophylaxis. The main purpose of this prospective observational study was to determine whether the low rate of CVC-related infection achieved by topical polyantibiotic ointment use during a randomized controlled trial would be observed during long-term prophylaxis as part of routine clinical care.

Similar Outcomes With Hemodialysis and Peritoneal Dialysis in Patients With End-Stage Renal Disease
The annual payer costs for patients treated with peritoneal dialysis (PD) are lower than with hemodialysis (HD), but in 2007, only 7% of dialysis patients in the United States were treated with PD. Since 1996, there has been no change in the first-year mortality of HD patients, but both short- and long-term outcomes of PD patients have improved. This article found that there was a progressive attenuation in the higher risk for death seen in patients treated with PD in earlier cohorts; for the 2002-2004 cohort, there was no significant difference in the risk of death for HD and PD patients through 5 years of follow-up. The median life expectancy of HD and PD patients was 38.4 and 36.6 months, respectively. Analyses in 8 subgroups based on age (<65 and 65 years), diabetic status, and baseline comorbidity (none and 1) showed greater improvement in survival among patients treated with PD relative to HD at all follow-up periods.

Interdialytic Hypertension—An Update
The reference standard for diagnosing hypertension among hemodialysis patients is 44-hour interdialytic ambulatory blood pressure (BP) recording. However, a more practical way to diagnose and manage hypertension is to measure home BP over the interdialytic interval. In contrast to pre- and postdialysis BP recordings, measurements of BP performed outside the dialysis unit correlate with the presence of left ventricular hypertrophy and directly and strongly with all-cause mortality....

Diastolic Heart Failure Versus Diastolic Dysfunction: Difference in Renal Function
Despite the common finding of diastolic dysfunction with a preserved ejection fraction on routine echocardiography in elderly patients, it is unknown why some patients with isolated diastolic dysfunction are asymptomatic whereas others develop diastolic heart failure (ie, signs and symptoms of congestive heart failure). This article hypothesized that renal insufficiency is more common in those patients with diastolic heart failure than those with diastolic dysfunction; it is intrinsic renal insufficiency that determines whether diastolic dysfunction becomes symptomatic. Multiple regression analysis showed only lower CrCl (44 ± 36 mL/min vs 76 ± 42 mL/min, total body weight, P = 0.0015; and 31 ± 24 mL/min vs 51 ± 27 mL/min, lean body mass, P = 0.0012) and eGFR (44 ± 33 mL/min/M2 vs 69 ± 28 mL/min/M2, P = 0.0003) were associated with diastolic heart failure. There was no significant difference in the presence of hypertension, diabetes, and coronary artery disease between groups. The results of this study support the hypothesis that patients with normal left ventricular ejection fractions but diastolic dysfunction develop congestive heart failure because of underlying renal insufficiency. A larger, prospective study is needed to confirm this hypothesis. 

Using Proteinuria and Estimated Glomerular Filtration Rate to Classify Risk in Patients With Chronic Kidney Disease
The staging system for chronic kidney disease relies almost exclusively on estimated glomerular filtration rate (eGFR), although proteinuria is also associated with adverse outcomes. This article attempted to validate a 5-category system for risk stratification based on the combination of eGFR and proteinuria. It found that using proteinuria in combination with eGFR may reduce unnecessary referrals for care at the cost of not referring or delaying referral for some patients who go on to develop kidney failure.

Urinary Albumin Versus Total Protein for Predicting Outcomes
Protein in the urine is one of the strongest predictors of kidney disease progression and cardiovascular risk. Recently, there has been debate as to which measure of proteinuria best predicts renal outcomes and mortality—total proteinuria or albuminuria—and in what clinical context. In this issue, Methven et al conduct a retrospective cohort study of 5,586 patients with CKD in Scotland and determine that total proteinuria, quantified as the urine total protein–creatinine ratio (TPCR), and albuminuria, quantified as the urine albumin-creatinine ratio (ACR), are associated with similar adjusted hazards for the outcomes of death, initiation of dialysis, and transplant, and doubling of serum creatinine. In an accompanying editorial, de Jong et al provide a historical review of the evolution of measures of proteinuria and a possible explanation for their equivalent performance in this study population.  

Spironolactone for difficult to control hypertension in chronic kidney disease
Spironolactone is effective at treating difficult to control hypertension in the general population, and it is unknown if it is safe or effective for those with chronic kidney disease (CKD) and difficult-to-control hypertension. In a retrospective cohort design, 88 patients with difficult-to-control hypertension study were assessed for blood pressure (BP) response to spironolactone as well as for biochemical changes. In the CKD group (34 patients), the average systolic BP (SBP) fell from 153 ± 18 to 143 ± 20 mm Hg (P = .006) compared with a fall in SBP from 150 ± 17 to 135 ± 17 mm Hg (P < .0001) in the non-CKD group (P < .0001). In 44% of those with CKD and 59% of those without CKD, SBP decreased by >10 mm Hg (defined as responders; P = .22). Potassium rose by 0.5 ± 0.6 mmol/L in the CKD group and 0.3 ± 0.5 mmol/L in the non-CKD group (P = .12). The overall incidence of hyperkalemia was 5.7% in the CKD group and 0% in the non-CKD group (P = .07). Spironolactone is associated with a significant fall in BP among those with CKD and difficult-to-control BP. It is associated with a modest rise in serum potassium, which is more pronounced among those with glomerular filtration rate below 45 mL/minute. For More Nephrology News Visit Our Nephrology Archives