Measuring the glomerular filtration rate in obese individuals without overt kidney disease.

Nephron Clin Pract. 2010;116(3):c224-34

Authors: Friedman AN, Strother M, Quinney SK, Hall S, Perkins SM, Brizendine EJ, Inman M, Gomez G, Shihabi Z, Moe S, Li L

Identifying methods to accurately measure the glomerular filtration rate (GFR) in obese individuals without kidney overt kidney disease is necessary to understanding the pathophysiology and natural history of obesity-related kidney disease.

PMID: 20606483 [PubMed - indexed for MEDLINE]

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Inpatient hemodialysis initiation: reasons, risk factors and outcomes.

Nephron Clin Pract. 2010;114(1):c19-28

Authors: Crews DC, Jaar BG, Plantinga LC, Kassem HS, Fink NE, Powe NR

BACKGROUND/AIMS: Inpatient initiation of chronic hemodialysis is considered undesirable because of cost and possible harms of hospitalization. We examined the patient characteristics and outcomes associated with inpatient initiation. METHODS: In a prospective cohort study of incident dialysis patients, the independent association of inpatient hemodialysis initiation with patient outcomes was assessed in multivariable analyses with adjustment for patient characteristics and propensity for inpatient initiation. RESULTS: A total of 410 of 652 (63%) hemodialysis patients began as inpatients; uremia and volume overload were the most commonly documented reasons. Compared to outpatients, inpatients were more likely to be unmarried, report less social support, have multiple comorbidities and be referred to a nephrologist 4 months or less prior to initiation. Inpatient initiation was protective for subsequent all-cause hospitalization (incidence rate ratio (IRR) = 0.92, confidence interval (CI) 0.89-0.94); this was most pronounced among those who had the highest propensity for inpatient initiation (IRR = 0.66, CI 0.56-0.78), including those referred late to nephrology. Similar results were found for infectious hospitalization. Mortality [hazard ratio = 1.03, CI 0.82-1.30] and cardiovascular events were not significantly different for inpatients versus outpatients. CONCLUSION: Inpatient hemodialysis initiation has a protective association with hospitalization among those patients referred late to nephrology, with multiple comorbidities and/or little social support.

PMID: 19816040 [PubMed - indexed for MEDLINE]

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The impact of admissions for the management of end-stage renal disease on hospital bed occupancy.

Nephron Clin Pract. 2009;113(4):c315-20

Authors: Quinn MP, Cardwell CR, Rainey A, McNamee PT, Kee F, Maxwell AP, Fogarty DG, Courtney AE

BACKGROUND: End-stage renal disease (ESRD) is increasingly prevalent but the inpatient costs associated with this condition are poorly defined due to limitations with data extraction and failure to differentiate between hospitalisation for renal and non-renal disease reasons. The impact of admissions primarily for the management of ESRD on hospital bed utilisation was assessed over a 5-year period in a large teaching hospital. METHODS: All admission episodes were reviewed and the ESRD group was identified by a primary International Classification of Diseases code for ESRD or a non-specific primary renal failure code with a secondary code for ESRD. The frequency and duration of hospitalisation and contribution to bed day occupancy of this group with ESRD was determined. RESULTS: There were 70,808 patients responsible for a total of 116,915 admissions and 919,212 bed days over the study period. Of these, 988 (1.4%) patients were admitted for the management of ESRD, accounting for 2,387 (2.0%) of admissions and utilisation of 23,011 (2.5%) bed days. After adjustment for age and gender, those admitted for ESRD management were significantly more likely to have a prolonged admission exceeding 30 days (odds ratio 1.46, 95% confidence interval 1.23-1.72, p < 0.001). When the admission was an emergency rather than an elective event, the patient was 4.6 times more likely to be hospitalised for over 30 days. CONCLUSIONS: Persons admitted for ESRD management are hospitalised more frequently and for longer than the overall inpatient population, occupying a substantial number of bed days.

PMID: 19729967 [PubMed - indexed for MEDLINE]

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Definition and classification of acute kidney injury.

Nephron Clin Pract. 2008;109(4):c182-7

Authors: Kellum JA, Bellomo R, Ronco C

Changes in urine output and glomerular filtration rate are neither necessary nor sufficient for the diagnosis of renal pathology. Yet no simple alternative for the diagnosis currently exists. Until recently, there has been no consensus as to diagnostic criteria or clinical definition of acute renal failure. Depending on the definition used, acute renal failure has been reported to affect from 1 to 25% of ICU patients and has led to mortality rates from 15 to 60%. The RIFLE criteria were developed to standardize the diagnosis of acute renal failure and in the process the term acute kidney injury (AKI) has been proposed to encompass the entire spectrum of the syndrome from minor changes in renal function to requirement for renal replacement therapy. Thus, AKI is not acute renal failure but a more general description. Small changes in kidney function in hospitalized patients are important and are associated with significant changes in short and possibly long-term outcomes. The RIFLE criteria provide a uniform definition of AKI and have now been validated in numerous studies.

PMID: 18802365 [PubMed - indexed for MEDLINE]

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Biomarkers for the diagnosis of acute kidney injury.

Nephron Clin Pract. 2008;109(4):c192-7

Authors: Waikar SS, Bonventre JV

The identification of acute kidney injury relies on tests like blood urea nitrogen and serum creatinine that were identified and incorporated into clinical practice several decades ago. This review summarizes clinical studies of newer biomarkers that may permit earlier and more accurate identification of acute kidney injury. The urine may contain sensitive and specific markers of kidney injury that are present due to either impaired tubular reabsorption and catabolism of filtered molecules or release of tubular cell proteins in response to ischemic or nephrotoxic injury. Many potential markers have been studied. Promising injury markers in the urine include N-acetyl-beta-D-glucosaminidase, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and interleukin-18. New biomarkers of kidney injury hold the promise of substantially improving the diagnostic approach to acute kidney injury. Adequately powered clinical studies of multiple biomarkers are needed to qualify the biomarkers before they can be fully adopted in clinical practice. Once adopted, more sensitive biomarkers of acute kidney injury hold the potential to transform the care of patients with renal disease.

PMID: 18802367 [PubMed - indexed for MEDLINE]

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Imaging techniques in acute kidney injury.

Nephron Clin Pract. 2008;109(4):c198-204

Authors: Sharfuddin AA, Sandoval RM, Molitoris BA

Multi-photon microscopy, along with advances in other imaging modalities, allows investigators the opportunity to study dynamic events within the functioning kidney. These emerging technologies enable investigators to follow complex heterogeneous processes in organs such as the kidney with improved spatial and temporal resolution, and sensitivity. Furthermore, the ability to obtain volumetric data (3-D) makes quantitative 4-D (time) analysis possible. Finally, use of up to three fluorophores concurrently in multi-photon microscopy allows for three different or interactive processes to be observed simultaneously. Therefore, this approach complements existing molecular, biochemical, pharmacologic and radiologic techniques by advancing data analysis and interpretation to subcellular levels for molecules without the requirement for fixation. Its use in acute kidney injury is in its infancy but offers much promise for unraveling the complex interdependent processes known to contribute to cell injury and organ failure. Also, recent advances in other imaging techniques offer potential clinical diagnostic tools to study acute kidney injury in animal models and in patients.

PMID: 18802368 [PubMed - indexed for MEDLINE]

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New insights on intravenous fluids, diuretics and acute kidney injury.

Nephron Clin Pract. 2008;109(4):c206-16

Authors: Townsend DR, Bagshaw SM

Acute kidney injury (AKI) is commonly and increasingly encountered in patients with critical illness. Fluid therapy is the cornerstone for the prevention and management of critically ill patients with AKI. New data have emerged that have raised concern that specific types of fluid (i.e. hydroxyethylstarch) may either contribute to or exacerbate AKI. Additional data have accumulated to indicate that the unnecessary accumulation of fluid and volume overload can negatively impact clinical outcomes. This finding may be further compounded in patients with oliguric AKI where solute and free water elimination are impaired. Diuretic therapy in AKI remains controversial. However, diuretic use is common, despite a paucity of evidence to show improved clinical outcomes. There are few therapeutic interventions proven to impact the clinical course and outcome of critically ill patients with established AKI. Current management strategies center largely on supportive care, with rapid resuscitation, removal of the stimulus contributing to AKI, judicious avoidance of complications, and allowing time for recovery. In this review, we explore recent insights on intravenous fluid therapy, volume overload, and diuretic therapy in the context of the critically ill patients with AKI.

PMID: 18802369 [PubMed - indexed for MEDLINE]

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Outcome prediction for patients with acute kidney injury.

Nephron Clin Pract. 2008;109(4):c217-23

Authors: Uchino S

BACKGROUND/AIMS: To review the currently available severity scores to predict outcome of acute kidney injury (AKI) patients, to discuss the problems with such scores, and to provide information for the development of more accurate AKI severity scores in the future. METHODS: Literature review and multivariate analysis using a large international database for AKI. RESULTS: Although general severity scores have good discrimination and calibration abilities to predict outcome of critically ill patients, the accuracy of these systems for AKI patients has been questioned. To improve prediction ability, multiple AKI severity scores have been published in the literature. However, most of these scores were developed and tested in a single center, or if multicentric, they were confined to a single country. Seven variables (mechanical ventilation, bilirubin, age, oliguria, hypotension, sepsis and platelet count) are often found as common risk factors in these severity scores and should be included in future AKI severity scores. Although several studies have consistently reported that both low creatinine and high urea at the start of RRT are related to worse outcome in AKI patients, they might not improve prediction ability. CONCLUSION: Using available information and a large database collected internationally, a more accurate score for AKI is likely to be developed.

PMID: 18802370 [PubMed - indexed for MEDLINE]

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Acute kidney injury: new concepts, renal recovery.

Nephron Clin Pract. 2008;109(4):c224-8

Authors: Bell M

BACKGROUND/AIMS: Long-term outcome after critical illness is important. After acute kidney injury (AKI) one measurement of such long-term outcome is assessment of renal recovery. METHODS: A literature search was performed using the Medline database from 1960 to the present. The attempt was to include major clinical trials and other systematic reviews published in the field of renal recovery after critical illness. RESULTS: More than 15 studies have covered the topic of renal outcome after intensive care, but the results are ambiguous. Studies from the mid-1990s showed that AKI survivors were at great risk of becoming dialysis dependent for life, with non-recovery reported at around 30%. Later investigations found lower risks, with non-recovery between 5 and 8% depending on the choice of continuous or intermittent renal replacement therapies. CONCLUSION: Continuous renal replacement therapies may be associated with better chances of renal recovery. Determining when and how to measure long-term renal outcome remains a matter of controversy.

PMID: 18802371 [PubMed - indexed for MEDLINE]

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Effects of sevelamer on the progression of vascular calcification in patients on chronic haemodialysis.

Nephron Clin Pract. 2008;108(4):c278-83

Authors: Takei T, Otsubo S, Uchida K, Matsugami K, Mimuro T, Kabaya T, Akiba T, Nitta K

BACKGROUND/AIM: Vascular calcification is thought to be associated with a high cardiovascular mortality rate in patients with end-stage renal disease. Control of hyperphosphataemia is important for the treatment of the vascular calcification. The aim of the present study was to evaluate the effects of sevelamer hydrochloride on the progression of aortic calcification in haemodialysis (HD) patients. METHODS: 42 HD patients were studied in this study and divided into two groups (sevelamer vs. calcium). Sevelamer was added and titrated up to achieve serum P control for 6 months. The estimations of aortic calcification index (ACI) by abdominal computed tomography scans were performed twice in each patient. We compared the changes in serum calcium, phosphorus, intact parathyroid hormone, and lipids in two groups. RESULTS: Serum phosphorus levels decreased significantly from 6.7 +/- 0.7 to 6.2 +/- 0.5 mg/dl with no changes in serum intact parathyroid hormone levels in the sevelamer group (p < 0.01), and increased from 6.5 +/- 1.0 to 6.7 +/- 1.1 mg/dl in the calcium group (p < 0.05). Serum calcium levels did not change in the sevelamer group and calcium group. The serum levels of total cholesterol decreased significantly from 158.5 +/- 20.7 to 146.2 +/- 24.1 mg/dl (p = 0.024) and the low-density lipoprotein cholesterol level from 65.3 +/- 14.4 to 54.7 +/- 11.6 mg/dl (p = 0.014) in the sevelamer group. Serum C-reactive protein decreased significantly from 0.14 +/- 0.13 to 0.08 +/- 0.11 mg/dl in the sevelamer group (p = 0.038) and significantly increased (0.18 +/- 0.09 vs. 0.22 +/- 0.12 mg/dl) in the calcium group (p = 0.042). The mean changes in ACI (DeltaACI) were 3.6 +/- 1.5% in the sevelamer group and 8.2 +/- 3.1% in the calcium group. CONCLUSIONS: Sevelamer allows a better serum phosphorus control compared with calcium-based phosphate binder and suppresses the progression of aortic calcification in HD patients.

PMID: 18434749 [PubMed - indexed for MEDLINE]

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