Correspondence LETTERS TO THE EDITOR A Perspective From the Baltics Regarding the Canadian Society of Nephrology Commentary on the KDIGO Glomerulonephritis Guideline
4. Meijers B, Maas RJH, Sprangers B, et al. The soluble urokinase receptor is not a clinical marker for focal segmental glomerulosclerosis. Kidney Int. 2014;85(3):636-640. 5. Sinha A, Bajpai J, Saini S, et al. Serum-soluble urokinase receptor levels do not distinguish focal segmental glomerulosclerosis from other causes of nephrotic syndrome in children. Kidney Int. 2014;85(3):649-658. 6. Wada T, Nangaku M, Maruyama S, et al. A multicenter cross-sectional study of circulating soluble urokinase receptor in Japanese patients with glomerular disease. Kidney Int. 2014;85(3): 641-648.
To the Editor: In their commentary on the 2012 KDIGO (Kidney Disease: Improving Global Outcomes) clinical practice guideline recommendations for glomerulonephritis (GN) in adults, Cybulsky et al1 correctly identify gaps in current knowledge regarding GN management. However, their statement that “GNs collectively account for approximately one-quarter of end-stage renal disease (ESRD)”1(p364) is an underestimation. GN-associated ESRD is much more common in sub-Saharan Africa and Asia.2 Further, community-wide incidence or prevalence of GN can be estimated only from kidney biopsy series, which are subject to bias because of differing criteria for biopsy.3 Moreover, the authors state that levels of a soluble form of urokinase-type plasminogen activator receptor (suPAR) are elevated in FSGS [focal segmental glomerulosclerosis] and that suPAR and other “novel biomarkers may provide insights into the pathogenesis of the disease and its activity, predict remission more accurately, and may lead to mechanism-based therapeutics.”1(p366) However, recent data show that serum suPAR levels are not reliable in distinguishing FSGS from other proteinuric glomerular diseases.4,5 Reduced estimated glomerular filtration rate makes suPAR an unreliable diagnostic biomarker in FSGS, and serum suPAR is influenced markedly by systemic inflammation, acute illnesses, cancer, and diabetes.6 Thus, serum suPAR cannot be considered a valid biomarker for either primary or secondary FSGS. Despite these concerns, I generally agree with Cybulsky et al, especially in the section on pauci-immune focal and segmental necrotizing GN, in which the authors point out that the guideline does not discuss glucocorticoids for maintenance therapy or the relative cost-effectiveness of rituximab. I concur that cost should be heeded when considering mycophenolate mofetil treatment for resistant disease. And, the authors’ observation that “[t]he challenge will be how to incorporate.management suggestions into.everyday practice” holds true for Lithuanian clinicians as well.
We appreciate the thoughtful comments from Dr Miglinas1 on the recently published Canadian Society of Nephrology commentary on the recommendations in the 2012 KDIGO clinical practice guideline on glomerulonephritis relevant to management of adult patients.2 The intent of the commentary, as with other CSN commentaries on KDIGO clinical practice guidelines, is to permit Canadian nephrologists to view the KDIGO guidelines through the lens of the Canadian practitioner. The incidence of GN-associated ESRD most assuredly varies by country, as Dr Miglinas correctly points out. The most recent data from Canada indicate that chronic GN accounted for 23.2% of incident and 21.3% of prevalent cases of ESRD in Canada in 2013.3 We agree with Dr Miglinas that recently described biomarkers such as suPAR are not yet ready for prime time. However, we would contend that the continued search for biomarkers that offer important insights into either diagnosis or management is a vital future research direction in glomerular disease. It seems probable that our current understanding of chronic glomerular disease is undergoing a major transformation.
Marius Miglinas, MD, PhD Vilnius University Vilnius, Lithuania
Norman Muirhead, MD, FRCPC, FRCP (Ed) Western University London, Canada
Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2014.04.033
In Reply to ‘A Perspective From the Baltics Regarding the Canadian Society of Nephrology Commentary on the KDIGO Glomerulonephritis Guideline’
Acknowledgements
Acknowledgements
Financial Disclosure: The author declares that he has no relevant financial interests.
Financial Disclosure: The author declares that he has no relevant financial interests.
References
References
1. Cybulsky AV, Walsh M, Knoll G, et al. Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guideline for glomerulonephritis: management of glomerulonephritis in adults. Am J Kidney Dis. 2014;63(3):363-377. 2. Jha V, Garcia-Garcia G, Iseki K, et al. Chronic kidney disease: global dimension and perspectives. Lancet. 2013;382(9888): 260-272. 3. Stewart JH, McCredie MR, Williams SM, et al. Trends in incidence of treated end-stage renal disease, overall and by primary renal disease, in persons aged 20-64 years in Europe, Canada and the Asia-Pacific region, 1998–2002. Nephrology (Carlton). 2007;12(5):520-527.
1. Miglinas M. A perspective from the Baltics regarding the Canadian Society of Nephrology commentary on the KDIGO glomerulonephritis guideline. Am J Kidney Dis. 2014;64(2):315. 2. Cybulsky AV, Walsh M, Knoll G, et al. Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guidelines for glomerulonephritis: management of glomerulonephritis in adults. Am J Kidney Dis. 2014;63(3):363-377. 3. Canadian Institute for Health Information; Statistics Canada. Canadian Organ Replacement Register. 2013.
Am J Kidney Dis. 2014;64(2):315-318
Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2014.05.012
315
4. Meijers B, Maas RJH, Sprangers B, et al. The soluble urokinase receptor is not a clinical marker for focal segmental glomerulosclerosis. Kidney Int. 2014;85(3):636-640. 5. Sinha A, Bajpai J, Saini S, et al. Serum-soluble urokinase receptor levels do not distinguish focal segmental glomerulosclerosis from other causes of nephrotic syndrome in children. Kidney Int. 2014;85(3):649-658. 6. Wada T, Nangaku M, Maruyama S, et al. A multicenter cross-sectional study of circulating soluble urokinase receptor in Japanese patients with glomerular disease. Kidney Int. 2014;85(3): 641-648.
To the Editor: In their commentary on the 2012 KDIGO (Kidney Disease: Improving Global Outcomes) clinical practice guideline recommendations for glomerulonephritis (GN) in adults, Cybulsky et al1 correctly identify gaps in current knowledge regarding GN management. However, their statement that “GNs collectively account for approximately one-quarter of end-stage renal disease (ESRD)”1(p364) is an underestimation. GN-associated ESRD is much more common in sub-Saharan Africa and Asia.2 Further, community-wide incidence or prevalence of GN can be estimated only from kidney biopsy series, which are subject to bias because of differing criteria for biopsy.3 Moreover, the authors state that levels of a soluble form of urokinase-type plasminogen activator receptor (suPAR) are elevated in FSGS [focal segmental glomerulosclerosis] and that suPAR and other “novel biomarkers may provide insights into the pathogenesis of the disease and its activity, predict remission more accurately, and may lead to mechanism-based therapeutics.”1(p366) However, recent data show that serum suPAR levels are not reliable in distinguishing FSGS from other proteinuric glomerular diseases.4,5 Reduced estimated glomerular filtration rate makes suPAR an unreliable diagnostic biomarker in FSGS, and serum suPAR is influenced markedly by systemic inflammation, acute illnesses, cancer, and diabetes.6 Thus, serum suPAR cannot be considered a valid biomarker for either primary or secondary FSGS. Despite these concerns, I generally agree with Cybulsky et al, especially in the section on pauci-immune focal and segmental necrotizing GN, in which the authors point out that the guideline does not discuss glucocorticoids for maintenance therapy or the relative cost-effectiveness of rituximab. I concur that cost should be heeded when considering mycophenolate mofetil treatment for resistant disease. And, the authors’ observation that “[t]he challenge will be how to incorporate.management suggestions into.everyday practice” holds true for Lithuanian clinicians as well.
We appreciate the thoughtful comments from Dr Miglinas1 on the recently published Canadian Society of Nephrology commentary on the recommendations in the 2012 KDIGO clinical practice guideline on glomerulonephritis relevant to management of adult patients.2 The intent of the commentary, as with other CSN commentaries on KDIGO clinical practice guidelines, is to permit Canadian nephrologists to view the KDIGO guidelines through the lens of the Canadian practitioner. The incidence of GN-associated ESRD most assuredly varies by country, as Dr Miglinas correctly points out. The most recent data from Canada indicate that chronic GN accounted for 23.2% of incident and 21.3% of prevalent cases of ESRD in Canada in 2013.3 We agree with Dr Miglinas that recently described biomarkers such as suPAR are not yet ready for prime time. However, we would contend that the continued search for biomarkers that offer important insights into either diagnosis or management is a vital future research direction in glomerular disease. It seems probable that our current understanding of chronic glomerular disease is undergoing a major transformation.
Marius Miglinas, MD, PhD Vilnius University Vilnius, Lithuania
Norman Muirhead, MD, FRCPC, FRCP (Ed) Western University London, Canada
Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2014.04.033
In Reply to ‘A Perspective From the Baltics Regarding the Canadian Society of Nephrology Commentary on the KDIGO Glomerulonephritis Guideline’
Acknowledgements
Acknowledgements
Financial Disclosure: The author declares that he has no relevant financial interests.
Financial Disclosure: The author declares that he has no relevant financial interests.
References
References
1. Cybulsky AV, Walsh M, Knoll G, et al. Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guideline for glomerulonephritis: management of glomerulonephritis in adults. Am J Kidney Dis. 2014;63(3):363-377. 2. Jha V, Garcia-Garcia G, Iseki K, et al. Chronic kidney disease: global dimension and perspectives. Lancet. 2013;382(9888): 260-272. 3. Stewart JH, McCredie MR, Williams SM, et al. Trends in incidence of treated end-stage renal disease, overall and by primary renal disease, in persons aged 20-64 years in Europe, Canada and the Asia-Pacific region, 1998–2002. Nephrology (Carlton). 2007;12(5):520-527.
1. Miglinas M. A perspective from the Baltics regarding the Canadian Society of Nephrology commentary on the KDIGO glomerulonephritis guideline. Am J Kidney Dis. 2014;64(2):315. 2. Cybulsky AV, Walsh M, Knoll G, et al. Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guidelines for glomerulonephritis: management of glomerulonephritis in adults. Am J Kidney Dis. 2014;63(3):363-377. 3. Canadian Institute for Health Information; Statistics Canada. Canadian Organ Replacement Register. 2013.
Am J Kidney Dis. 2014;64(2):315-318
Ó 2014 by the National Kidney Foundation, Inc. http://dx.doi.org/10.1053/j.ajkd.2014.05.012
315
