letter to the editor
1 0.8 0.6 HD pts group 0.4
PD pts group CPH pts group
0.2 0 0
20
40
60
80
100
120
Time (months)
Figure 1 | Three groups were matched with age, gender, underlying disease, and prevalence of cardiovascular disease. The cumulative survival rate did not differ significantly between groups (log-rank P = 0.20).
technique survival for some PD patients by permitting those struggling to maintain adequate solute and water clearance to continue PD. A single weekly HD session could optimize dialysis for marginal PD patients, including larger patients, low transporters, and those without significant residual renal function. The downside of CPD would be the requirement for dual PD and vascular access, potentially increasing risk of infection. Alternatively, the presence of an arteriovenous graft or fistula would ease the transition to HD when the time came for a permanent switch. In the United States and countries with diverse demographics, larger observational studies are needed to determine whether CPD would be an acceptable alternative to PD or HD alone, and to determine whether CPD is associated with a survival benefit. 1.
2.
In 2013, approximately 1900 patients (20% of all PD patients) were receiving this therapy in Japan (Japanese Society for Dialysis Therapy, unpublished data). CPH may increase the indications for PD in the United States. 1.
2.
3.
Kumar VA, Sidell MA, Jones JP et al. Survival of propensity matched incident peritoneal and hemodialysis patients in a United States health care system. Kidney Int 2014; 86: 1016–1022. Matsuo N, Yokoyama K, Maruyama Y et al. Clinical impact of a combined therapy of peritoneal dialysis and hemodialysis. Clin Nephrol 2010; 74: 209–216. Kimura K, Ogura M, Yokoyama K et al. A reason for choosing peritoneal dialysis: lessons after the Japan earthquake and the Fukushima nuclear accident. Am J Kidney Dis 2012; 60: 327.
1
1
Matsuo N, Yokoyama K, Tanno Y et al. Combined therapy using peritoneal dialysis and hemodialysis may increase the indications for peritoneal dialysis in the United States. Kidney Int 2015; 87: 1267–1268. Agarwal M, Clinard P, Burkart JM. Combined peritoneal dialysis and hemodialysis: our experience compared to others. Perit Dial Int 2003; 23: 157–161.
Victoria A. Kumar1, Margo A. Sidell2, Jason P. Jones2 and Edward F. Vonesh3 1 Division of Nephrology, Department of Internal Medicine, Southern California Permanente Medical Group, Los Angeles, California, USA; 2Research and Evaluation, Southern California Permanente Medical Group, Pasadena, California, USA and 3Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Correspondence: Victoria A. Kumar, Division of Nephrology, Department of Internal Medicine, Southern California Permanente Medical Group, 4700 Sunset Boulevard, Los Angeles, California 90027, USA. E-mail: [email protected].
Kidney International (2015) 87, 1260; doi:10.1038/ki.2015.55
1
Nanae Matsuo , Keitaro Yokoyama , Yudo Tanno , Izumi Yamamoto1 and Takashi Yokoo1 1
Division of Nephrology and Hypertension, Department of Internal Medicine, Tokyo, Japan Correspondence: Keitaro Yokoyama, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University Schoool of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8471, Japan. E-mail: [email protected] Kidney International (2015) 87, 1259–1260; doi:10.1038/ki.2015.56
The Authors Reply: We thank Matsuo et al.1 for their comment regarding combined peritoneal and hemodialysis (CPD). The simultaneous use of peritoneal (PD) and hemodialysis (HD) offers a viable solution in emergency situations and may afford potential benefits to a subgroup of PD patients2. The current US shortage of PD solutions has been a challenge for PD programs, many of which have struggled to place new patients on PD in the latter half of 2014. CPD could have alleviated the situation by permitting flexibility in the dialysis prescription for new and existing patients. CPD could be considered a self-care dialysis option augmented by in-center HD. It could potentially increase 1260
Regarding mini-review on bicarbonate therapy for prevention of chronic kidney disease progression To the Editor: The mini-review on bicarbonate therapy for prevention of chronic kidney disease progression1 was a much-needed, well-written, and informative review. It has long been known that chronic acidosis seen in chronic kidney disease (CKD) 4 and 5 has a deleterious effect on digestion and general nutrition. The recommendation of rigorous treatment to prevent progression of CKD was well explained by various recently reported pathophysiological mechanisms that support the urgency of treatment. However, there was a recommendation in the management that is a cause of concern. Because of the probability of poor compliance and intolerance with administration of NaHCO3 compounds, the authors recommend other alkali products—e.g., Shohl’s solution (sodium citrate and citric acid) or polycitra (citric acid, potassium citrate, and sodium citrate)—as alternatives. They do issue a warning of the dangers of increased Kidney International (2015) 87, 1258–1264
letter to the editor
aluminum (Al) absorption in patients taking Al-containing phosphate binders but did not elaborate on this point. We showed that ingestion of a low dose of citrate contained in a well-known effervescent calcium supplement taken by normal volunteers as well as subjects with stable chronic renal failure resulted in an increase in the excretion of urinary Al in normal individuals and an increase in both serum and urine Al in those with CKD.2 The experiments showing this were accompanied by a low dose of Al hydroxide supplementation. The point of the research, however, was to alert medical practitioners that, even without Al supplementation, patients with CKD 3b, 4, and 5 may experience an increase in serum and urine Al if receiving compounds containing citrate. This is because all foodstuffs in a powdery form contain Al to prevent them from congealing, as AL has hydrophobic properties. For this reason we believe that all citratecontaining preparations are totally contraindicated because of the Al contained in, e.g., flour, custard powder, salt, sugar, etc. Although the bicarbonate powder may occasionally be unpleasant to take, it is safe and inexpensive, and the unpleasant taste can be disguised. 1.
2.
Łoniewski I, Wesson DE. Bicarbonate therapy for prevention of chronic kidney disease progression. Kidney Int 2014; 85: 529–535. Nestel AW, Meyers AM, Paiker J et al. Effect of calcium supplement preparation containing small amounts of citrate on the absorption of aluminium in normal subjects and in renal failure patients. Nephron 1994; 68: 197–201.
Anthony M. Meyers1,2
diet alone4,5 or in combination with sodium bicarbonate6 might be an effective alternative approach. Ongoing clinical studies of sodium bicarbonate therapy in CKD patients should also bring more light on the efficacy and tolerability of alkali therapy.7 1. 2.
3.
4.
5.
6.
7.
Meyers A. Regarding mini-review on bicarbonate therapy for prevention of chronic kidney disease progression. Kidney Int 2015; 87: 1268–1269. Breitkreutz J, Gan TG, Schneider B et al. Enteric-coated solid dosage forms containing sodium bicarbonate as a drug substance: an exception from the rule? J Pharm Pharmacol 2007; 59: 59–65. Rossier A, Bullani R, Burnier M et al. Bicarbonate de sodium pour ralentir la progression de la maladie rénale chronique. Rev Med Suisse 2011; 7: 478–482. Goraya N, Simoni J, Jo CH et al. A comparison of treating metabolic acidosis in CKD stage 4 hypertensive kidney disease with fruits and vegetables or sodium bicarbonate. Clin J Am Soc Nephrol 2013; 8: 371–381. Goraya N, Simoni J, Jo CH et al. Treatment of metabolic acidosis in patients with stage 3 chronic kidney disease with fruits and vegetables or oral bicarbonate reduces urine angiotensinogen and preserves glomerular filtration rate. Kidney Int 2014; 86: 1031–1038. Loniewski I. Combining a fruit and vegetable diet with sodium bicarbonate supplementation seems the best dietary option for chronic kidney disease patients. Kidney Int. 2012; 82: 937. Dobre M, Rahman M, Hostetter TH. Current status of bicarbonate in CKD. J Am Soc Nephrol 2014; 26: 515–523.
Igor Łoniewski1 and Donald E. Wesson2,3 1
Sanum Polska Sp. z o.o. ul. Kurza Stopka 5/c, Szczecin, Poland; 2Departments of Internal Medicine, Baylor Scott and White Health, Temple, Texas, USA and 3 Texas A&M Health Sciences Center College of Medicine, Temple, Texas, USA Correspondence: Donald E. Wesson, Texas A&M Health Sciences Center College of Medicine, Baylor Scott and White Health, 2401 South 31st Street, Temple 76508, Texas, USA. E-mail: [email protected] Kidney International (2015) 87, 1261; doi:10.1038/ki.2015.84
1
Dialysis Unit, WITS Donald Gordon Medical Centre, Johannesburg, South Africa and 2Division of Nephrology, Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa Correspondence: Anthony M. Meyers, Division of Nephrology, Department of Medicine, University of the Witwatersrand, 402 Waterfall Hills, Private Bag x 5, SunnighHill, Johannesburg 2157, South Africa. E-mail: [email protected]
Intravenous iron dose and mortality in hemodialysis patients
Kidney International (2015) 87, 1260–1261; doi:10.1038/ki.2015.81
The Authors Reply: We thank Professor Meyers for his welcomed comment that citrate intake is responsible for increase in blood and urine aluminum concentration and therefore should be avoided in chronic treatment of metabolic acidosis.1 We agree and suggest that sodium bicarbonate is preferable to sodium citrate as alkali therapy. Galenic forms of sodium bicarbonate should be palatable, easy to swallow, and have pharmaceutical purity and quality. Interestingly, the galenic form of sodium bicarbonate is available as an enteric capsule, which dissolves in intestines.2,3 As such, bicarbonate anions are directly absorbed into the blood. Although we are not aware of clinical studies testing this in CKD patients, it seems that this strategy for sodium bicarbonate administration should yield good clinical efficacy and few if any side effects (e.g., carbon dioxide will not be produced in the stomach). In addition, alkali therapy with fruit and vegetable Kidney International (2015) 87, 1258–1264
To the Editor: There is an important misunderstanding evident in the commentary by Weiss and Kronenberg1 addressing our article2 describing an association between high-dose intravenous iron and mortality in hemodialysis patients. The editorialists state that ‘patients receiving higher dosages of iron also received higher dosages of erythropoiesisstimulating agent (ESA), pointing to bone marrow hyporesponsiveness. It is therefore also conceivable that higher ESA rather than increased iron dosages contribute to mortality in such subjects …’.1 As shown in Table 2 of the manuscript, however, even after adjustment for ESA dose and hemoglobin concentration, average monthly intravenous iron doses ⩾ 400 mg/month were associated with significantly increased mortality compared with the most common doses of 100–199 mg/month (hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.0–1.28) and intravenous iron doses ⩾ 300 mg/ month were associated with significantly increased mortality compared with doses o300 mg/month (HR 1.10; 95% CI 1.03–1.17).2 It is therefore incorrect to ascribe to concomitant ESA administration the observed mortality 1261
1 0.8 0.6 HD pts group 0.4
PD pts group CPH pts group
0.2 0 0
20
40
60
80
100
120
Time (months)
Figure 1 | Three groups were matched with age, gender, underlying disease, and prevalence of cardiovascular disease. The cumulative survival rate did not differ significantly between groups (log-rank P = 0.20).
technique survival for some PD patients by permitting those struggling to maintain adequate solute and water clearance to continue PD. A single weekly HD session could optimize dialysis for marginal PD patients, including larger patients, low transporters, and those without significant residual renal function. The downside of CPD would be the requirement for dual PD and vascular access, potentially increasing risk of infection. Alternatively, the presence of an arteriovenous graft or fistula would ease the transition to HD when the time came for a permanent switch. In the United States and countries with diverse demographics, larger observational studies are needed to determine whether CPD would be an acceptable alternative to PD or HD alone, and to determine whether CPD is associated with a survival benefit. 1.
2.
In 2013, approximately 1900 patients (20% of all PD patients) were receiving this therapy in Japan (Japanese Society for Dialysis Therapy, unpublished data). CPH may increase the indications for PD in the United States. 1.
2.
3.
Kumar VA, Sidell MA, Jones JP et al. Survival of propensity matched incident peritoneal and hemodialysis patients in a United States health care system. Kidney Int 2014; 86: 1016–1022. Matsuo N, Yokoyama K, Maruyama Y et al. Clinical impact of a combined therapy of peritoneal dialysis and hemodialysis. Clin Nephrol 2010; 74: 209–216. Kimura K, Ogura M, Yokoyama K et al. A reason for choosing peritoneal dialysis: lessons after the Japan earthquake and the Fukushima nuclear accident. Am J Kidney Dis 2012; 60: 327.
1
1
Matsuo N, Yokoyama K, Tanno Y et al. Combined therapy using peritoneal dialysis and hemodialysis may increase the indications for peritoneal dialysis in the United States. Kidney Int 2015; 87: 1267–1268. Agarwal M, Clinard P, Burkart JM. Combined peritoneal dialysis and hemodialysis: our experience compared to others. Perit Dial Int 2003; 23: 157–161.
Victoria A. Kumar1, Margo A. Sidell2, Jason P. Jones2 and Edward F. Vonesh3 1 Division of Nephrology, Department of Internal Medicine, Southern California Permanente Medical Group, Los Angeles, California, USA; 2Research and Evaluation, Southern California Permanente Medical Group, Pasadena, California, USA and 3Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Correspondence: Victoria A. Kumar, Division of Nephrology, Department of Internal Medicine, Southern California Permanente Medical Group, 4700 Sunset Boulevard, Los Angeles, California 90027, USA. E-mail: [email protected].
Kidney International (2015) 87, 1260; doi:10.1038/ki.2015.55
1
Nanae Matsuo , Keitaro Yokoyama , Yudo Tanno , Izumi Yamamoto1 and Takashi Yokoo1 1
Division of Nephrology and Hypertension, Department of Internal Medicine, Tokyo, Japan Correspondence: Keitaro Yokoyama, Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University Schoool of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8471, Japan. E-mail: [email protected] Kidney International (2015) 87, 1259–1260; doi:10.1038/ki.2015.56
The Authors Reply: We thank Matsuo et al.1 for their comment regarding combined peritoneal and hemodialysis (CPD). The simultaneous use of peritoneal (PD) and hemodialysis (HD) offers a viable solution in emergency situations and may afford potential benefits to a subgroup of PD patients2. The current US shortage of PD solutions has been a challenge for PD programs, many of which have struggled to place new patients on PD in the latter half of 2014. CPD could have alleviated the situation by permitting flexibility in the dialysis prescription for new and existing patients. CPD could be considered a self-care dialysis option augmented by in-center HD. It could potentially increase 1260
Regarding mini-review on bicarbonate therapy for prevention of chronic kidney disease progression To the Editor: The mini-review on bicarbonate therapy for prevention of chronic kidney disease progression1 was a much-needed, well-written, and informative review. It has long been known that chronic acidosis seen in chronic kidney disease (CKD) 4 and 5 has a deleterious effect on digestion and general nutrition. The recommendation of rigorous treatment to prevent progression of CKD was well explained by various recently reported pathophysiological mechanisms that support the urgency of treatment. However, there was a recommendation in the management that is a cause of concern. Because of the probability of poor compliance and intolerance with administration of NaHCO3 compounds, the authors recommend other alkali products—e.g., Shohl’s solution (sodium citrate and citric acid) or polycitra (citric acid, potassium citrate, and sodium citrate)—as alternatives. They do issue a warning of the dangers of increased Kidney International (2015) 87, 1258–1264
letter to the editor
aluminum (Al) absorption in patients taking Al-containing phosphate binders but did not elaborate on this point. We showed that ingestion of a low dose of citrate contained in a well-known effervescent calcium supplement taken by normal volunteers as well as subjects with stable chronic renal failure resulted in an increase in the excretion of urinary Al in normal individuals and an increase in both serum and urine Al in those with CKD.2 The experiments showing this were accompanied by a low dose of Al hydroxide supplementation. The point of the research, however, was to alert medical practitioners that, even without Al supplementation, patients with CKD 3b, 4, and 5 may experience an increase in serum and urine Al if receiving compounds containing citrate. This is because all foodstuffs in a powdery form contain Al to prevent them from congealing, as AL has hydrophobic properties. For this reason we believe that all citratecontaining preparations are totally contraindicated because of the Al contained in, e.g., flour, custard powder, salt, sugar, etc. Although the bicarbonate powder may occasionally be unpleasant to take, it is safe and inexpensive, and the unpleasant taste can be disguised. 1.
2.
Łoniewski I, Wesson DE. Bicarbonate therapy for prevention of chronic kidney disease progression. Kidney Int 2014; 85: 529–535. Nestel AW, Meyers AM, Paiker J et al. Effect of calcium supplement preparation containing small amounts of citrate on the absorption of aluminium in normal subjects and in renal failure patients. Nephron 1994; 68: 197–201.
Anthony M. Meyers1,2
diet alone4,5 or in combination with sodium bicarbonate6 might be an effective alternative approach. Ongoing clinical studies of sodium bicarbonate therapy in CKD patients should also bring more light on the efficacy and tolerability of alkali therapy.7 1. 2.
3.
4.
5.
6.
7.
Meyers A. Regarding mini-review on bicarbonate therapy for prevention of chronic kidney disease progression. Kidney Int 2015; 87: 1268–1269. Breitkreutz J, Gan TG, Schneider B et al. Enteric-coated solid dosage forms containing sodium bicarbonate as a drug substance: an exception from the rule? J Pharm Pharmacol 2007; 59: 59–65. Rossier A, Bullani R, Burnier M et al. Bicarbonate de sodium pour ralentir la progression de la maladie rénale chronique. Rev Med Suisse 2011; 7: 478–482. Goraya N, Simoni J, Jo CH et al. A comparison of treating metabolic acidosis in CKD stage 4 hypertensive kidney disease with fruits and vegetables or sodium bicarbonate. Clin J Am Soc Nephrol 2013; 8: 371–381. Goraya N, Simoni J, Jo CH et al. Treatment of metabolic acidosis in patients with stage 3 chronic kidney disease with fruits and vegetables or oral bicarbonate reduces urine angiotensinogen and preserves glomerular filtration rate. Kidney Int 2014; 86: 1031–1038. Loniewski I. Combining a fruit and vegetable diet with sodium bicarbonate supplementation seems the best dietary option for chronic kidney disease patients. Kidney Int. 2012; 82: 937. Dobre M, Rahman M, Hostetter TH. Current status of bicarbonate in CKD. J Am Soc Nephrol 2014; 26: 515–523.
Igor Łoniewski1 and Donald E. Wesson2,3 1
Sanum Polska Sp. z o.o. ul. Kurza Stopka 5/c, Szczecin, Poland; 2Departments of Internal Medicine, Baylor Scott and White Health, Temple, Texas, USA and 3 Texas A&M Health Sciences Center College of Medicine, Temple, Texas, USA Correspondence: Donald E. Wesson, Texas A&M Health Sciences Center College of Medicine, Baylor Scott and White Health, 2401 South 31st Street, Temple 76508, Texas, USA. E-mail: [email protected] Kidney International (2015) 87, 1261; doi:10.1038/ki.2015.84
1
Dialysis Unit, WITS Donald Gordon Medical Centre, Johannesburg, South Africa and 2Division of Nephrology, Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa Correspondence: Anthony M. Meyers, Division of Nephrology, Department of Medicine, University of the Witwatersrand, 402 Waterfall Hills, Private Bag x 5, SunnighHill, Johannesburg 2157, South Africa. E-mail: [email protected]
Intravenous iron dose and mortality in hemodialysis patients
Kidney International (2015) 87, 1260–1261; doi:10.1038/ki.2015.81
The Authors Reply: We thank Professor Meyers for his welcomed comment that citrate intake is responsible for increase in blood and urine aluminum concentration and therefore should be avoided in chronic treatment of metabolic acidosis.1 We agree and suggest that sodium bicarbonate is preferable to sodium citrate as alkali therapy. Galenic forms of sodium bicarbonate should be palatable, easy to swallow, and have pharmaceutical purity and quality. Interestingly, the galenic form of sodium bicarbonate is available as an enteric capsule, which dissolves in intestines.2,3 As such, bicarbonate anions are directly absorbed into the blood. Although we are not aware of clinical studies testing this in CKD patients, it seems that this strategy for sodium bicarbonate administration should yield good clinical efficacy and few if any side effects (e.g., carbon dioxide will not be produced in the stomach). In addition, alkali therapy with fruit and vegetable Kidney International (2015) 87, 1258–1264
To the Editor: There is an important misunderstanding evident in the commentary by Weiss and Kronenberg1 addressing our article2 describing an association between high-dose intravenous iron and mortality in hemodialysis patients. The editorialists state that ‘patients receiving higher dosages of iron also received higher dosages of erythropoiesisstimulating agent (ESA), pointing to bone marrow hyporesponsiveness. It is therefore also conceivable that higher ESA rather than increased iron dosages contribute to mortality in such subjects …’.1 As shown in Table 2 of the manuscript, however, even after adjustment for ESA dose and hemoglobin concentration, average monthly intravenous iron doses ⩾ 400 mg/month were associated with significantly increased mortality compared with the most common doses of 100–199 mg/month (hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.0–1.28) and intravenous iron doses ⩾ 300 mg/ month were associated with significantly increased mortality compared with doses o300 mg/month (HR 1.10; 95% CI 1.03–1.17).2 It is therefore incorrect to ascribe to concomitant ESA administration the observed mortality 1261
