Journal of the Formosan Medical Association (2015) 114, 94
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.jfma-online.com
LETTER TO THE EDITOR
Renoprotective effect of pentoxifylline in advanced chronic kidney disease KEYWORDS ACE inhibitor; angiotensin II receptor blocker; chronic kidney disease; pentoxifylline
progression risk factors not obtained for comparison, including hypertension, smoking history, HbA1c, the “mean” blood pressure and daily urine protein amount during follow up. The above nonmentioned risks may have impacts on the final results. Thirdly, different classes, doses, and duration of ACEI and ARB use may still be an important factor to attend to.
References I read with interest the article: “Renoprotective effect of combining pentoxifylline with angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker in advanced chronic kidney disease.”1 Based on this finding, add-on therapy pentoxifylline with angiotensin converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) is associated with better renal outcome in moderate to severe [estimated glomerular filtration rate (eGFR) < 45 mL/minute/1.73 m2] chronic kidney disease (CKD) patients. The benefit was especially prominent in high proteinuria (1 g/day) patients. However, no benefit of reducing proteinuria was found in the study group, which is different from several previous studies.2 As proteinuria is commonly used as a surrogate outcome for renal function, there was a discrepancy between renal outcome and proteinuria. Perkins et al3 hypothesized pentoxifylline has a greater impact on anti-inflammation of the tubuleintestinal fibrosis than protein filtration. It may warrant further studies to clarify the effects of this drug. As the authors reported, the strength of this study was the largest sample size to date. However, I still want to point out several caveats. Firstly, “initiation of dialysis” is the only primary end point. I wonder if the end point set as “eGFR declining rate” or “doubling of serum creatinine” will carry out similar results. Secondly, as a retrospective design, there are several confounding factors, such as CKD
1. Chen PM, Lai TS, Chen PY, Lai CF, Wu V, Chiang WC, et al. Renoprotective effect of combining pentoxifylline with angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker in advanced chronic kidney disease. J Formos Med Assoc 2014;113(4):219e26. 2. McCormick BB, Sydor A, Akbari A, Fergusson D, Doucette S, Knoll G. The effect of pentoxifylline on proteinuria in diabetic kidney disease: a meta-analysis. Am J Kidney Dis 2008;52(3):454e63. 3. Perkins RM, Aboudara MC, Uy AL, Olson SW, Cushner HM, Yuan CM. Effect of pentoxifylline on GFR decline in CKD: a pilot, double-blind, randomized, placebo-controlled trial. Am J Kidney Dis 2009;53(4):606e16.
Chih-Chin Kao Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan Mai-Szu Wu* Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan Department of Internal Medicine, School of Medicine, Taipei Medical University, Taipei 110, Taiwan *Corresponding author. Taipei Medical University, Number 252, Wu Hsing Street, Taipei 110, Taiwan. E-mail address: [email protected]
Conflicts of interest: The authors declare that there is no conflict of interest regarding the publication of this article. http://dx.doi.org/10.1016/j.jfma.2014.05.005 0929-6646/Copyright ª 2014, Elsevier Taiwan LLC & Formosan Medical Association. All rights reserved.
17 April 2014
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.jfma-online.com
LETTER TO THE EDITOR
Renoprotective effect of pentoxifylline in advanced chronic kidney disease KEYWORDS ACE inhibitor; angiotensin II receptor blocker; chronic kidney disease; pentoxifylline
progression risk factors not obtained for comparison, including hypertension, smoking history, HbA1c, the “mean” blood pressure and daily urine protein amount during follow up. The above nonmentioned risks may have impacts on the final results. Thirdly, different classes, doses, and duration of ACEI and ARB use may still be an important factor to attend to.
References I read with interest the article: “Renoprotective effect of combining pentoxifylline with angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker in advanced chronic kidney disease.”1 Based on this finding, add-on therapy pentoxifylline with angiotensin converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) is associated with better renal outcome in moderate to severe [estimated glomerular filtration rate (eGFR) < 45 mL/minute/1.73 m2] chronic kidney disease (CKD) patients. The benefit was especially prominent in high proteinuria (1 g/day) patients. However, no benefit of reducing proteinuria was found in the study group, which is different from several previous studies.2 As proteinuria is commonly used as a surrogate outcome for renal function, there was a discrepancy between renal outcome and proteinuria. Perkins et al3 hypothesized pentoxifylline has a greater impact on anti-inflammation of the tubuleintestinal fibrosis than protein filtration. It may warrant further studies to clarify the effects of this drug. As the authors reported, the strength of this study was the largest sample size to date. However, I still want to point out several caveats. Firstly, “initiation of dialysis” is the only primary end point. I wonder if the end point set as “eGFR declining rate” or “doubling of serum creatinine” will carry out similar results. Secondly, as a retrospective design, there are several confounding factors, such as CKD
1. Chen PM, Lai TS, Chen PY, Lai CF, Wu V, Chiang WC, et al. Renoprotective effect of combining pentoxifylline with angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker in advanced chronic kidney disease. J Formos Med Assoc 2014;113(4):219e26. 2. McCormick BB, Sydor A, Akbari A, Fergusson D, Doucette S, Knoll G. The effect of pentoxifylline on proteinuria in diabetic kidney disease: a meta-analysis. Am J Kidney Dis 2008;52(3):454e63. 3. Perkins RM, Aboudara MC, Uy AL, Olson SW, Cushner HM, Yuan CM. Effect of pentoxifylline on GFR decline in CKD: a pilot, double-blind, randomized, placebo-controlled trial. Am J Kidney Dis 2009;53(4):606e16.
Chih-Chin Kao Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan Mai-Szu Wu* Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan Department of Internal Medicine, School of Medicine, Taipei Medical University, Taipei 110, Taiwan *Corresponding author. Taipei Medical University, Number 252, Wu Hsing Street, Taipei 110, Taiwan. E-mail address: [email protected]
Conflicts of interest: The authors declare that there is no conflict of interest regarding the publication of this article. http://dx.doi.org/10.1016/j.jfma.2014.05.005 0929-6646/Copyright ª 2014, Elsevier Taiwan LLC & Formosan Medical Association. All rights reserved.
17 April 2014
