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Abdelhafez MO, Alhroob AA, Abu Hawilla MO, Rjoob AA, Abualia NM, Gorman EF, Hamadah AM, Gharaibeh KA. Utility of fractional excretion of urea in acute kidney injury with comparison to fractional excretion of sodium: A systematic review and meta-analysis. Am J Med Sci 2024:S0002-9629(24)01220-5. [PMID: 38768779 DOI: 10.1016/j.amjms.2024.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 02/28/2024] [Accepted: 04/18/2024] [Indexed: 05/22/2024]
Abstract
BACKGROUND Differentiating between intrinsic and prerenal acute kidney injury (AKI) presents a challenge. Here, we assessed the performance of the fractional excretion of urea (FEUrea) and compared it to the fractional excretion of sodium (FENa) in distinguishing intrinsic from prerenal AKI. METHODS A thorough search was conducted in several databases until January 16, 2024. We included studies evaluating FEUrea, with or without FENa, for differentiating AKI etiologies in adults. We assessed the methodological quality using the QUADAS-2 and QUADAS-C tools. We performed a meta-analysis using the bivariate random effects model, with subgroup analyses to explore the impact of diuretic therapy on FEUrea, and direct statistical comparisons between FEUrea and FENa involving the subgroups with and without diuretics. RESULTS We included 11 studies with 1108 hospitalized patients. Among eight studies (915 patients) evaluating FEUrea >35% for distinguishing intrinsic from prerenal AKI, the pooled sensitivity and specificity were 66% (95% CI, 49%-79%) and 75% (95% CI, 60%-85%), respectively. In a subset of six studies (302 patients) comparing FEUrea at 35% to FENa at 1% in patients not receiving diuretics, there were no significant differences in sensitivity (77% versus 89%, P = 0.410) or specificity (80% versus 79%, P = 0.956). In four studies, 244 patients on diuretics, FEUrea demonstrated lower sensitivity (52% versus 92%, P < 0.001) but higher specificity (82% versus 44%, P < 0.001) compared to FENa for the diagnosis of intrinsic AKI. CONCLUSIONS FEUrea has limited utility in differentiating intrinsic from prerenal AKI. FEUrea does not provide a superior alternative to FENa, even in patients receiving diuretics.
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Affiliation(s)
- Mohammad O Abdelhafez
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine
| | - Asil A Alhroob
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine
| | - Mustafa O Abu Hawilla
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine
| | - Asmaa A Rjoob
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine
| | - Nasser M Abualia
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine
| | - Emily F Gorman
- Health Sciences and Human Services Library, University of Maryland, Baltimore, MD, USA
| | | | - Kamel A Gharaibeh
- Department of Internal Medicine, Al-Quds University, Abu Dis, Jerusalem, State of Palestine; Division of Pulmonary & Critical Care Medicine, University of Maryland, School of Medicine, Baltimore, MD, USA.
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Buckenmayer A, Siebler N, Haas CS. Evaluation of simple diagnostic parameters in acute kidney injury in hospitalized patients-diagnostic recommendations for non-nephrologists. Intern Emerg Med 2023; 18:1769-1776. [PMID: 37452960 PMCID: PMC10504189 DOI: 10.1007/s11739-023-03365-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/03/2023] [Indexed: 07/18/2023]
Abstract
Acute kidney injury (AKI) is very common in hospitalized patients, affecting patient's mortality and morbidity. Major causes are prerenal AKI and acute tubular necrosis (ATN). Even though a variety of parameters/indices exist, their reliability and practicability are controversial: in fact, there is a need for a simple diagnostic approach for AKI in in-patients with parameters easily obtained in any hospital. The objective of the study was: (1) to assess reliability of simple laboratory parameters/indices to differentiate pre-/intrarenal AKI; (2) to evaluate the most reliable and feasible parameters/indices; and (3) to identify the possible impact of confounding factors. Retrospectively, in-patients with AKI hospitalized in 2020 in a university nephrology department were included. Spot urine and 24-h collection urine was analyzed with urine sodium (UNa), urine specific gravity (USG), fractional excretion of sodium (FENa), fractional excretion of urea (FEUrea), urine osmolality (UOsm), urine to plasma creatinine ratio (UCr/PCr) and renal failure index (RFI). Overall, 431 patients were included. UNa, UOsm, USG and RFI showed high specificity > 85% for prerenal AKI, UNa and RFI provided good specificity for ATN. Loop diuretics, ACE inhibitors/AT1 blockers or pre-existing chronic kidney disease had no impact. In patients with AKI, UNa, USG and RFI: (1) proved to be very specific for prerenal AKI and showed high sensitivity for ATN; (2) can be easily determined using serum and spot urine; and (3) are not confounded by medication or comorbidities. These parameters/indices are helpful to identify the aetiology of AKI and to guide therapy, thereby improving patients' safety and outcome.
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Affiliation(s)
- Anna Buckenmayer
- Department of Internal Medicine, Nephrology & Intensive Care Medicine, Phillips University, Baldinger Straße 1, 35043, Marburg, Germany.
| | - Nadja Siebler
- Department of Internal Medicine, Nephrology & Intensive Care Medicine, Phillips University, Baldinger Straße 1, 35043, Marburg, Germany
| | - Christian S Haas
- Department of Internal Medicine, Nephrology & Intensive Care Medicine, Phillips University, Baldinger Straße 1, 35043, Marburg, Germany
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Abdelhafez M, Nayfeh T, Atieh A, AbuShamma O, Babaa B, Baniowda M, Hrizat A, Hasan B, Hassett L, Hamadah A, Gharaibeh K. Diagnostic Performance of Fractional Excretion of Sodium for the Differential Diagnosis of Acute Kidney Injury: A Systematic Review and Meta-Analysis. Clin J Am Soc Nephrol 2022; 17:785-797. [PMID: 35545442 PMCID: PMC9269645 DOI: 10.2215/cjn.14561121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 04/06/2022] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES AKI is classified as prerenal, intrinsic, and postrenal. Prerenal AKI and intrinsic AKI represent the most common causes for AKI in hospitalized patients. This study aimed to examine the accuracy of the fractional excretion of sodium for distinguishing intrinsic from prerenal AKI. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, the Cochrane Library, and Scopus for all available studies that met the criteria until December 31, 2021. We included studies that evaluated fractional excretion of sodium in differentiating AKI etiologies in adults, whereas studies that did not have sufficient data to extract a 2×2 table were excluded. We assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and extracted the diagnostic accuracy data for all included studies. We conducted a meta-analysis using the bivariate random effects model. We performed subgroup analysis to investigate sources of heterogeneity and the effect of the relevant confounders on fractional excretion of sodium accuracy. RESULTS We included 19 studies with 1287 patients. In a subset of 15 studies (872 patients) that used a threshold of 1%, the pooled sensitivity and specificity for differentiating intrinsic from prerenal AKI were 90% (95% confidence interval, 81% to 95%) and 82% (95% confidence interval, 70% to 90%), respectively. In a subgroup of six studies (511 patients) that included CKD or patients on diuretics, the pooled sensitivity and specificity were 83% (95% confidence interval, 64% to 93%) and 66% (95% confidence interval, 51% to 78%), respectively. In five studies with 238 patients on diuretics, the pooled sensitivity and specificity were 80% (95% confidence interval, 69% to 87%) and 54% (95% confidence interval, 31% to 75%), respectively. In eight studies with 264 oliguric patients with no history of CKD or diuretic therapy, the pooled sensitivity and specificity were 95% (95% confidence interval, 82% to 99%) and 91% (95% confidence interval, 83% to 95%), respectively. CONCLUSIONS Fractional excretion of sodium has a limited role for AKI differentiation in patients with a history of CKD or those on diuretic therapy. It is most valuable when oliguria is present.
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Affiliation(s)
- Mohammad Abdelhafez
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Tarek Nayfeh
- Evidence-Based Practice Research Program, Mayo Clinic, Rochester, Minnesota.,Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, Minnesota
| | - Anwar Atieh
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Omar AbuShamma
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Basheer Babaa
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Muath Baniowda
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Alaa Hrizat
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine
| | - Bashar Hasan
- Evidence-Based Practice Research Program, Mayo Clinic, Rochester, Minnesota.,Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, Minnesota
| | - Leslie Hassett
- Mayo Clinic Libraries, Mayo Clinic, Rochester, Minnesota
| | | | - Kamel Gharaibeh
- Department of Internal Medicine, Al-Quds University, Jerusalem, State of Palestine .,Division of Pulmonary & Critical Care, University of Maryland, Baltimore, Maryland
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El-Khoury JM, Hoenig MP, Jones GRD, Lamb EJ, Parikh CR, Tolan NV, Wilson FP. AACC Guidance Document on Laboratory Investigation of Acute Kidney Injury. J Appl Lab Med 2021; 6:1316-1337. [PMID: 33973621 DOI: 10.1093/jalm/jfab020] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/15/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND Acute kidney injury (AKI) is a sudden episode of kidney damage or failure affecting up to 15% of hospitalized patients and is associated with serious short- and long-term complications, mortality, and health care costs. Current practices to diagnose and stage AKI are variable and do not factor in our improved understanding of the biological and analytical variability of creatinine. In addition, the emergence of biomarkers, for example, cystatin C, insulin-like growth factor binding protein 7, and tissue inhibitor of metalloproteinases 2, and electronic notification tools for earlier detection of AKI, highlights the need for updated recommendations to address these developments. CONTENT This AACC Academy guidance document is intended to provide laboratorians and clinicians up-to-date information regarding current best practices for the laboratory investigation of AKI. Topics covered include: clinical indications for further investigating potential AKI, analytical considerations for creatinine assays, the impact of biological variability on diagnostic thresholds, defining "baseline" creatinine, role of traditional markers (urine sodium, fractional excretion of sodium, fractional excretion of urea, and blood urea-to-creatinine ratio), urinary microscopic examination, new biomarkers, improving AKI-associated test utilization, and the utility of automated AKI alerts. SUMMARY The previous decade brought us a significant number of new studies characterizing the performance of existing and new biomarkers, as well as potential new tools for early detection and notification of AKI. This guidance document is intended to inform clinicians and laboratorians on the best practices for the laboratory investigation of AKI, based on expert recommendations where the preponderance of evidence is available.
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Affiliation(s)
- Joe M El-Khoury
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Melanie P Hoenig
- Renal Division, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | - Edmund J Lamb
- Department of Pathology, East Kent Hospitals University NHS Foundation Trust, Kent, UK
| | - Chirag R Parikh
- Division of Nephrology, Johns Hopkins University, Baltimore, MD, USA
| | - Nicole V Tolan
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA, USA
| | - F Perry Wilson
- Program of Applied Translational Research, Yale School of Medicine, New Haven, CT, USA
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