Outcome Measures Used to Report Kidney Function in Studies Investigating Surgical Management of Kidney Tumours: A Systematic Review

Most practice decisions relevant to preserving kidney function in patients managed surgically for kidney tumours are driven by observational studies. A wide range of outcome measures are used in these studies, which reduces comparability and increases the risk of reporting bias.

To comprehensively and succinctly describe the outcomes used to evaluate kidney function in studies evaluating surgical management of kidney tumours.

Electronic search of the PubMed database was conducted to identify studies with at least one measure of kidney function in patients managed surgically for kidney tumours, published between January 2000 and September 2017. Abstracts were initially screened for eligibility. Full texts of articles were then evaluated in more detail for inclusion. A narrative synthesis of the evidence was conducted.

A total of 312 studies, involving 127905 participants, were included in this review. Most were retrospective (n=274) studies and conducted in a single centre (n=264). Overall, 78 unique outcome measures were identified, which were grouped into six outcome categories. Absolute postoperative kidney function (n=187), relative kidney function (n=181), and postoperative chronic kidney disease (n=131) were most frequently reported. Kidney function was predominantly quantified using estimated glomerular filtration rate or creatinine clearance (n=255), most using the modification of diet in renal disease equation (n=182). Only 70 studies provided rationale for specific outcome measures used.

There is significant variability in the reporting and quantification of kidney function in studies evaluating patients managed surgically for kidney tumours. A standardised approach to measuring and reporting kidney function will increase the effectiveness of outcomes reported and improve relevance of research findings within a clinical context.

Although we know that the removal of a kidney can reduce kidney function, clinical significance of various approaches is a matter of debate. This article demonstrates significant variability in the way kidney function was reported across all studies of patients with kidney cancer undergoing surgery, indicating a need for standardisation.

European urology focus. 2018 May 01 [Epub ahead of print]

Robert J Ellis, Yeoungjee Cho, Sharon J Del Vecchio, Megan McStea, Christudas Morais, Jeff S Coombes, Simon T Wood, Glenda C Gobe, Ross S Francis

Centre for Kidney Disease Research, University of Queensland Faculty of Medicine, Translational Research Institute, Brisbane, Australia; Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia. Electronic address: ., Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia; Australasian Kidney Trials Network, University of Queensland, Brisbane, Australia., Centre for Kidney Disease Research, University of Queensland Faculty of Medicine, Translational Research Institute, Brisbane, Australia; Department of Urology, Princess Alexandra Hospital, Brisbane, Australia., Australasian Kidney Trials Network, University of Queensland, Brisbane, Australia., Centre for Kidney Disease Research, University of Queensland Faculty of Medicine, Translational Research Institute, Brisbane, Australia., School of Human Movement and Nutrition Science, University of Queensland, Brisbane, Australia; NHMRC Chronic Kidney Disease Centre for Research Excellence, University of Queensland, Brisbane, Australia., Centre for Kidney Disease Research, University of Queensland Faculty of Medicine, Translational Research Institute, Brisbane, Australia; NHMRC Chronic Kidney Disease Centre for Research Excellence, University of Queensland, Brisbane, Australia., Centre for Kidney Disease Research, University of Queensland Faculty of Medicine, Translational Research Institute, Brisbane, Australia; Department of Nephrology, Princess Alexandra Hospital, Brisbane, Australia.

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