***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: CONTEXT Although acute renal failure ( ARF ) is believed to be common in the setting of critical illness and is associated with a high risk of death , little is known about its epidemiology and outcome or how these vary in different regions of the world . OBJECTIVES To determine the period prevalence of ARF in intensive care unit ( ICU ) patients in multiple countries ; to characterize differences in etiology , illness severity , and clinical practice ; and to determine the impact of these differences on patient outcomes . DESIGN , SETTING , AND PATIENTS Prospect i ve observational study of ICU patients who either were treated with renal replacement therapy ( RRT ) or fulfilled at least 1 of the predefined criteria for ARF from September 2000 to December 2001 at 54 hospitals in 23 countries . MAIN OUTCOME MEASURES Occurrence of ARF , factors contributing to etiology , illness severity , treatment , need for renal support after hospital discharge , and hospital mortality . RESULTS Of 29 269 critically ill patients admitted during the study period , 1738 ( 5.7 % ; 95 % confidence interval [ CI ] , 5.5%-6.0 % ) had ARF during their ICU stay , including 1260 who were treated with RRT . The most common contributing factor to ARF was septic shock ( 47.5 % ; 95 % CI , 45.2%-49.5 % ) . Approximately 30 % of patients had preadmission renal dysfunction . Overall hospital mortality was 60.3 % ( 95 % CI , 58.0%-62.6 % ) . Dialysis dependence at hospital discharge was 13.8 % ( 95 % CI , 11.2%-16.3 % ) for survivors . Independent risk factors for hospital mortality included use of vasopressors ( odds ratio [ OR ] , 1.95 ; 95 % CI , 1.50 - 2.55 ; P<.001 ) , mechanical ventilation ( OR , 2.11 ; 95 % CI , 1.58 - 2.82 ; P<.001 ) , septic shock ( OR , 1.36 ; 95 % CI , 1.03 - 1.79 ; P = .03 ) , cardiogenic shock ( OR , 1.41 ; 95 % CI , 1.05 - 1.90 ; P = .02 ) , and hepatorenal syndrome ( OR , 1.87 ; 95 % CI , 1.07 - 3.28 ; P = .03 ) . CONCLUSION In this multinational study , the period prevalence of ARF requiring RRT in the ICU was between 5 % and 6 % and was associated with a high hospital mortality rate PURPOSE Patients with malignant hematologic disorders undergoing bone marrow transplantation ( BMT )  may develop renal insufficiency . A study was undertaken to assess prospect ively the sub clinical renal function changes with radioisotopic methods in patients undergoing BMT for hematologic malignancies . METHODS AND MATERIAL S We studied 71 patients with normal renal function undergoing BMT for various hematologic malignancies , mostly leukemias . Conditioning included  chemotherapy and 12 Gy ( 45 patients ) or 13.5 Gy  ( 26 patients ) fractionated total-body irradiation ( TBI ) . In 21 patients receiving 12 Gy TBI  , the kidney dose was limited to 10 Gy using partial transmission blocks fabricated after renal opacification with nonionic , hypo-osmolar contrast medium . The glomerular filtration rate ( GFR ) and effective renal plasmatic flow ( ERPF ) were determined radioisotopically before conditioning and at 4 , 12 , and 18 months , using (51)Cr ethylene-diamine-tetra-acetic acid and (131)I ortho-iodo-hippurate , respectively . Renal insufficiency was defined as a decrease of > /=30 % in GFR or ERPF compared with the baseline values . The potential influence of patient- and treatment-related variables on renal dysfunction was assessed . RESULTS At 4 ( early ) and 12 - 18 ( late ) months , a > /=30 % GFR drop was observed in 54 % and 49 % of patients and a > /=30 % ERPF drop in 44 % and 34 % of patients , respectively . After stepwise logistic analysis , a GFR reduction at 4 months correlated significantly with age ( < 40 years old , worse ) , TBI using kidney blocks ( partial kidney shielding to 10 Gy was associated with a higher rate of renal dysfunction at 4 months compared with the full TBI dose ) , and days of aminoglycoside/vancomycin use . An ERPF drop at 4 months was independently related with the days of amphotericin use and days of prostagl and in E(1 ) use ( prophylaxis against hepatic venoocclusive disease ) . A GFR and ERPF reduction at 12 - 18 months correlated with days of amphotericin use and days of prostagl and in E(1 ) use , respectively . CONCLUSION Early post-BMT renal dysfunction is associated with the administration of potentially nephrotoxic drugs . An inverse correlation with the prescribed TBI dose was observed ; patients whose kidneys received 10 Gy through the use of partial shielding blocks had significantly greater renal dysfunction at 4 months . The administration of potentially nephrotoxic contrast agents used in radiotherapy treatment planning may be responsible for the latter observation . Prostagl and in E(1 ) use correlated with a significant reduction in ERPF at both 4 and 12 - 18 months To assess the efficacy and safety of amphotericin B colloidal dispersion ( ABCD ) , 82 patients with proven or probable aspergillosis who were treated in clinical trials with ABCD were compared retrospectively with 261 patients with aspergillosis who were treated with amphotericin B at six cancer or transplant centers from January 1990 to June 1994 . The groups were balanced in terms of underlying disease ; ABCD recipients were younger and more likely to have preexisting renal insufficiency than were amphotericin B recipients ( 40.7 % vs. 8.7 % , respectively ) , and amphotericin B recipients were more likely to be neutropenic at baseline than were ABCD recipients ( 42.5 % vs. 15.9 % , respectively ) . Response rates ( 48.8 % ) and survival rates ( 50 % ) among ABCD-treated patients were higher than those ( 23.4 % and 28.4 % , respectively ) among amphotericin B-treated patients ( P < .001 for both comparisons ) . Renal dysfunction developed less frequently in ABCD recipients than in amphotericin B recipients ( 8.2 % vs. 43.1 % , respectively ; P < .001 ) . Multivariate analysis revealed that treatment group was the best predictor of response , mortality , and nephrotoxicity ( ABCD : relative risk [ RR ] = 3.00 , P = .002 ; RR = 0.35 , P < .001 ; and RR = 0.13 , P = .001 ; respectively ) . This retrospective study suggests that in the treatment of aspergillosis ABCD causes fewer nephrotoxic effects than amphotericin B and the efficacy of ABCD is at least comparable with that of amphotericin The glomerular filtration rate ( GFR ) is traditionally considered the best overall index of renal function in health and disease ( 1 ) . Because GFR is difficult to measure in clinical practice , most clinicians estimate the GFR from the serum creatinine concentration . However , the accuracy of this estimate is limited because the serum creatinine concentration is affected by factors other than creatinine filtration ( 2 , 3 ) . To circumvent these limitations , several formulas have been developed to estimate creatinine clearance from serum creatinine concentration , age , sex , and body size ( 4 - 12 ) . Despite more recent studies that have related serum creatinine concentration to GFR ( 13 - 24 ) , no formula is more widely used to predict creatinine clearance than that proposed by Cockcroft and Gault ( 4 ) . This formula is used to detect the onset of renal insufficiency , to adjust the dose of drugs excreted by the kidney , and to evaluate the effectiveness of therapy for progressive renal disease . More recently , it has been used to document eligibility for reimbursement from the Medicare End Stage Renal Disease Program ( 25 ) and for accrual of points for patients on the waiting list for cadaveric renal transplantation ( 26 ) . Major clinical decisions in general medicine , geriatrics , and oncology ( as well as nephrology ) are made by using the Cockcroft-Gault formula and other formulas to predict the level of renal function . Therefore , these formulas must predict GFR as accurately as possible . The Modification of Diet in Renal Disease ( MDRD ) Study , a multicenter , controlled trial , evaluated the effect of dietary protein restriction and strict blood pressure control on the progression of renal disease ( 27 - 30 ) . During the baseline period , GFR , serum creatinine , and several variables that affect the relation between them were measured in patients with chronic renal disease . The purpose of our study was to develop an equation from MDRD Study data that could improve the prediction of GFR from serum creatinine concentration . Methods Baseline Cohort and Measurement Methods in the Modification of Diet in Renal Disease Study The overall study design and methods of recruitment for the MDRD Study have been described elsewhere ( 31 , 32 ) . A total of 1785 patients entered the baseline period . Of these patients , 1628 ( 91 % ) also underwent measurement of GFR  and the other variables described below ; these patients constitute the study group for these analyses . Glomerular filtration rate was measured as the renal clearance of 125I-iothalamate ( 33 , 34 ) . Creatinine clearance was computed from creatinine excretion in a 24-hour urine collection and a single measurement of serum creatinine . Serum and urine creatinine were measured by using a kinetic alkaline picrate assay with a normal range in serum of 62 to 124 mol/L ( 0.7 to 1.4 mg/dL ) ( 35 ) . Glomerular filtration rate and creatinine clearance were expressed per 1.73 m2 of body surface area by multiplying measured values by 1.73/body surface area ( 36 ) . The serum and urine specimens were also used for other measurements , including serum albumin ( bromcresol green method [ 35 ] ) , serum urea nitrogen ( urease method [ 35 ] ) , and urine urea nitrogen ( urease method [ 35 ] ) . Protein intake ( g/d ) was estimated as 6.25 [ UUN ( g/d ) + 0.031 ( g/kg per day ) SBW ( kg ) ] , where UUN is urine urea nitrogen , SBW is st and ard body weight , and 0.031 g/kg per day is a constant reflecting the rate of excretion of nitrogen in compounds other than urine urea ( 37 , 38 ) . The diagnosis of diabetes and the cause of renal disease were assigned on the basis of chart review at the clinical center ( 39 ) . Statistical Analysis Descriptive Statistics The relation of renal function measurements to other baseline characteristics was assessed by using contingency tables , t-tests , analysis of variance , and linear regression , as appropriate . Nonparametric tests ( Wilcoxon rank-sum tests and Kruskal-Wallis tests ) gave consistent results . A P value less than 0.01 was considered statistically significant . Multivariable Analysis of Glomerular Filtration Rate We used stepwise multiple regression to determine a set of variables that jointly predicted GFR . The stepwise regression models were developed by using a training sample consisting of a r and om sample of 1070 of the 1628 patients . We found that the variability of the difference between the observed and predicted GFR values was greater for higher GFR values . This increase was eliminated by performing multiple regressions on log-transformed data . To facilitate clinical interpretation , the results were re-expressed in terms of the original units . Consequently , the prediction equation is a multiplicative model ; regression coefficients refer to the change in geometric mean GFR associated with unit changes in the independent variable . Predicted GFR is expressed in mL/min per 1.73 m2 . The following variables were considered for possible inclusion in the regression model : weight , height , sex , ethnicity , age , diagnosis of diabetes , serum creatinine concentration , serum urea nitrogen level , serum albumin level , serum phosphorus level , serum calcium level , mean arterial pressure , urine creatinine level , urine urea nitrogen level , urine protein level , and urine phosphorus level . The cause of renal disease was not included because in clinical practice , the cause may be unknown or clinicians may not use the same classification method as the investigators in the MDRD Study . A P value less than 0.001 was used as the criterion for entry of a variable into the model . Because of the difficulty in collecting complete 24-hour urine sample s in clinical practice , an additional stepwise regression was performed to develop a prediction model that did not include urine biochemistry variables . Finally , because of the interest in developing a prediction equation to assess eligibility for Medicare reimbursement and listing for cadaveric renal transplantation , we repeated the analysis restricting the population to the subgroup of patients with higher serum creatinine concentrations ( > 221 mol/L [ 2.5 mg/dL ] 
    Output:
    
Based on our review we conclude that lipid formulations of amphotericin B are an important strategy to preserve renal function and improve survival in critically ill patients who require treatment for systemic fungal infections