RESEARCH BRIEF

Nutritional Management of HyperkalemicInfants With Chronic Kidney Disease,Using Adult Renal FormulasDavid J. Hobbs, MBSc, Tracy R. Gast, RD, Karen B. Ferguson, RD, CNSD,

Timothy E. Bunchman, MD, and Gina-Marie Barletta, MD

Objective: This study sought to evaluate the use of adult renal formulas in hyperkalemic infants with chronic

kidney disease (CKD).

Design: This was a retrospective, single-center cohort study.

Setting: This study took place at the Department of Pediatric Nephrology, Dialysis, and Transplantation at Helen

DeVos Children’s Hospital (Grand Rapids, MI).

Patients: Seven hyperkalemic infants (mean age, 6.9 months) comprised the study population: 29% with stage

3 CKD, 29% with stage 4 CKD, and 42% with stage 5 CKD.

Intervention: Infants were empirically treated with adult renal formulas for an average duration of 9.6 months. Six

of seven infants were started on breast milk or infant formula (Similac PM 60/40, Abbott Laboratories, Columbus,

OH), but because of inadequate growth and hyperkalemia, were transitioned to adult renal formulas (Suplena, Abbott

Laboratories, Columbus, OH; Nepro, Abbott Laboratories, Columbus, OH; and/or Renalcal, Nestle Nutrition, Minne-

tonka, MN). One infant received adult renal formula at birth.

Main Outcome Measures: The outcome measures included amount of potassium delivered by infant and adult

renal formulas, level of serum potassium, and anthropometric measurements adjusted for age and gender (z-scores).

Results: The transition from infant to adult renal formula resulted in a decrease in mean amount of potassium

delivered by formula (from 2.6 to 1.0 mEq/kg/day, P , .001) and a decrease in mean serum potassium (from 5.1 to

4.0 mmol/L, P , .01). During treatment with adult renal formula, the infants demonstrated a significant increase in

mean weight z-score (from 21.0 to 0.5, P , .01), height z-score (from 21.9 to 20.5, P , .01), and head-circumference

z-score (from 21.5 to 21.0, P 5 .03). Adult renal formulas were well-tolerated.

Conclusions: Hyperkalemic infants with CKD can be nutritionally managed on adult renal formula.

� 2010 by the National Kidney Foundation, Inc. All rights reserved

IN INFANTS WITH chronic kidney disease(CKD), it is often difficult to supply sufficient

calories for growth and development because ofuremia, anorexia, and sometimes gastroesophageal

Department of Pediatric Nephrology, Dialysis, and Transplanta-

tion, Helen DeVos Children’s Hospital and Michigan State Univer-

sity College of Human Medicine, Grand Rapids, Michigan.

Address reprint requests to Timothy E. Bunchman, MD,

Department of Pediatric Nephrology, Dialysis and Transplantation,

Helen DeVos Children’s Hospital, 221 Michigan St. NE, Suite

406, Grand Rapids, MI 49503. E-mail: timothy.bunchman@devoschildrens.org

� 2010 by the National Kidney Foundation, Inc. All rights

reserved.

1051-2276/10/2002-0009$36.00/0

doi:10.1053/j.jrn.2009.06.003

Journal of Renal Nutrition, Vol 20, No 2 (March), 2010: pp 121–126

reflux.1,2 In the lower proportion of infants withanuria as opposed to polyuria, the relative volumeof feeds can be very problematic.3,4 Increased nu-tritional delivery with low-potassium infant renalformula may potentiate hyperkalemia secondaryto underlying renal dysfunction.5

Infant formulas used in the hyperkalemic CKDpopulation have predominantly been limited tobreast milk, Similac PM 60/40 (Abbott Laborato-ries, Columbus, OH), or standard formulas that arepotassium-depleted, using potassium-exchangeresins such as Kayexalate (Sanofi-Aventis, Bridge-water, NJ).6–8 Adult renal formulas are classically2 kcal/mL, and low in electrolytes. We hypothe-sized that the use of adult renal formulas, eitheralone or blended with infant and/or other adult

121

HOBBS ET AL122

renal formulas, may offer an alternative to the useof potassium-exchange resins. This study soughtto evaluate the amount of potassium delivered,and the growth response, among hyperkalemic in-fants with CKD empirically treated with adult re-nal formula.

Methods

The clinical, treatment, and laboratory data ofseven hyperkalemic infants with CKD empiricallytreated with adult renal formulas were retrospec-tively analyzed. The indications for transitionfrom infant to adult renal formula (or the use ofadult formula from birth) were elevated serumpotassium levels and poor growth. Primary out-come measures included the amount of potassiumdelivered by formula, serum potassium levels, andanthropometric measures corrected for age andgender (z-scores). Secondary outcome measuresincluded the volume, calories, protein, osmolality,and minerals delivered with adult renal formula.This study was approved by the Spectrum HealthInstitutional Review Board.

Specified nutritional therapy was based on theindividual needs of hyperkalemic infants withCKD. Infant renal formula consisted of SimilacPM 60/40 (Abbott Laboratories, Columbus,OH). Adult renal formulas consisted of Renalcal(Nestle Nutrition, Minnetonka, MN), Suplena(Ross), and Nepro (Ross). The difference be-tween Suplena and Nepro primarily involvesprotein (44.7 mEq/L vs. 81 mEq/L, respectively),and Renalcal is essentially depleted of Na, K, Ca,and Phos. Overall potassium exposure wasreduced in polyuric infants by blending SimilacPM 60/40, water, and adult renal formula fora high-volume, dilute, low-potassium formula,whereas in anuric infants, adult renal formulaswere blended in the absence of Similac PM 60/40 for a low-volume, highly concentrated, low-potassium formula.

When serum sodium and urinary sodium labo-ratory studies revealed salt-wasting in a polyuricinfant with hyperkalemia, 3.5 to 4.0 mEq/kg ofsodium (either with chloride or bicitrate) wasadded to feeds, which facilitated sodium andpotassium cation balance and a putative reductionin serum potassium.3 Dietary calcium and phos-phorous were routinely adjusted, based on serumstudies (phosphorous, calcium, and intact parathy-roid hormone), using sodium phosphate (NaPhos,

American Regent, Inc., Shirley, NY) and vitaminD supplementation. A water-soluble multivitamin(Strovite, Everett Laboratories, West Orange, NJ)was prescribed to maintain recommended vitamindietary reference intakes. During regular clinicalvisits (biweekly to monthly), the volume of feedswas changed according to gain in body weightand urinary output. Caloric and protein-formulaprescriptions were adjusted up or down dependingon changes in anthropometric indices and bloodurea nitrogen, respectively. No infants receivedgrowth hormone.

Infant and adult renal-formula prescriptions, aswell serum potassium levels and anthropometricz-scores, were compared using a paired t-test.P , .05 was considered statistically significant.Continuous data are described as mean 6 SD.

Results

Patient characteristics are listed in Table 1. Thestudy population consisted of infants with obstruc-tive uropathy, congenital nephrotic syndrome,cortical necrosis, renal dysplasia, polycystic kidneydisease, and branchio-oto-renal syndrome; 57%were polyuric, and 43% were anuric. Six of sevenchildren had received gastrostomy tubes andNissen fundoplication, and one of seven wasadministered formula orally.

Six of seven infants were initially administeredbreast milk and/or Similac PM 60/40, and oneof seven infants was fed formula from birth. Allinfants were administered Strovite multivitaminsupplementation. The mean age at time of transi-tion from infant to adult renal formula was 6.9months, and the mean duration of treatmentwith adult renal formula was 9.6 months.

Adult renal formula prescriptions are alsodescribed in Table 1. The transition from infantto adult renal formula resulted in a significantdecrease in mean amount of potassium deliveredto patients (2.6 6 0.2 mEq/kg/day vs. 1.0 6 0.2mEq/kg/day, P ,.001; Fig. 1A), as well as a signif-icant decrease in mean serum potassium(5.1 6 1.0 mmol/L vs. 4.0 6 0.9 mmol/L, P ,

.01; Fig. 1B). Infant and adult renal-formulaprescriptions were comparable in terms of calories(119 kcal/kg/day vs. 121 kcal/kg/day, P 5.29),protein (3.2 6 0.6 g/kg/day vs. 3.2 6 0.5 g/kg/day, P 5.28), sodium (1.21 6 0.1 mEq/kg/dayvs. 1.1 6 0.6 mEq/kg/day, P 5.71), and magne-sium (4.6 6 0.2 mg/kg/day vs. 6.4 6 9.3 mg/

Table 1. Characteristics and Formula Prescriptions of Hyperkalemic Infants With CKD, Empirically Transitioned From Infant to Adult Renal Formula

Patient

Renal

Diagnosis

CKD

Stage

Formula

Prescription

Volume(mL/kg/

day)

CaloricDensity

(kcal/mL)

Osm(mOsm/

kg H2O)

Calories

(kcal/kg/day)

Protein

(g/kg/day)

K(mEq/kg/

day)

Na(mEq/kg/

day)

Calcium(mEq/kg/

day)

Phosphorus(mEq/kg/

day)

Mg

(mg/kg/day)

1 Obstructive

uropathy

3 (P) 200 mL Suplena,

200 mL Renalcal, and

900 mL H2O

217 0.6 185 127 2.6 1.0 1.1 1.8 2.2 7.0

2 Cortical

necrosis

3 (P) 400 mL Similac,

360 mL Renalcal, and

400 mL H2O

146 0.9 193 124 2.9 0.7 0.3 0.9 0.8 2.0

3 Cortical

necrosis

4 (P) 300 mL Suplena,

300 mL Renalcal,

900 mL H2O, and

ProMod

150 0.8 240 117 2.9 0.9 1.0 1.6 2.0 6.2

4 Renal

dysplasia

4 (P) 240 mL Similac,

180 mL Renalcal,

200 mL H2O,

and ProMod

157 0.9 275 127 2.9 0.8 0.4 1.1 1.0 2.4

5 Congenital

nephrotic

syndrome

5 (A) 240 mL Suplena,

120 mL Renalcal,

60 mL H2O, andProMod

78 1.7 514 130 3.7 1.3 1.5 2.4 2.9 9.3

6 Autosomal-

recessive

PCKD

5 (A) 270 mL Nepro,

120 Renalcal,

60 ml H2O

69 1.6 511 110 3.9 1.1 1.9 2.2 2.7 8.5

7 Brachio-oto-

renal

syndrome

5 (A) 300 ml Suplena,

120 Renalcal,

90 mL H2O,

and ProMod

75 1.5 494 115 3.7 1.3 1.5 2.3 2.9 9.1

PCKD, polycystic kidney disease; P, polyuria; A, anuria; Similac, Similac PM 60/40; ProMod, protein supplementation; Osm, osmolality; K, potassium; Na, sodium; Mg,

magnesium.

AD

ULT

RE

NA

LF

OR

MU

LA

SF

OR

HY

PE

RK

AL

EM

ICC

KD

INFA

NT

S123

0

1

2

3

Infant Formula Adult Formula

Time

Pot

assi

um

del

iver

ed(m

Eq

/kg/

day

) A

**

22.5

33.5

44.5

55.5

66.5

7

Infant Formula Adult Formula

Time

Seru

m p

otas

siu

m(m

mol

/L)

B

*

Figure 1. Changes in (A) meanamounts of potassium deliveredby infant and adult formula pre-scriptions, and (B) changes in se-rum potassium levels ofhyperkalemic infants with CKD,after transitioning from infant toadult renal formula. *P , .01.**P , .001.

HOBBS ET AL124

kg/day, P 5 0.21). Adult renal-formula prescrip-tions delivered significantly less calcium (3.2 6

0.3 mEq/kg/day vs. 1.8 6 0.6 mEq/kg/day,P , .01) and phosphorus (3.2 6 0.3 mEq/kg/dayvs. 2.1 6 0.9 mEq/kg/day, P 5.05), and were ad-justed based on serum studies using NaPhos and vi-tamin D supplementation.

Polyuric infants were administered dilute,high-volume feeds with a mean osmolality of223 6 42 mOsm/kg H2O, whereas anuric infantswere administered concentrated, low-volume feedswith a mean osmolality of 506 6 11 mOsm/kgH2O (Table 1). Despite concerns regarding hyper-osmolar formulas, none of the anuric infantsdemonstrated significant gastrointestinal intoler-ance, as indicated by normal stooling and a lack ofvomiting or signs of gastrointestinal distress.

Before the intervention with adult renal for-mula, the infants demonstrated poor growth rates.The transition from infant to adult renal formularesulted in a significant increase in weight z-score(from 21.0 6 0.5 to 0.5 6 0.6, P ,.01; Fig. 2A),height z-score (from 21.9 6 0.2 to 20.5 6 0.6,P , 0.01; Fig. 2B), and head circumferencez-score (from 21.5 6 1.4 to 21.0 6 1.2,P 5.03; Fig. 2C).

Discussion

One of the major goals in infants with severerenal disease is to achieve an appropriate size (large

enough) for transplantation.9 Meeting normalnutritional requirements in infants with CKDmay be difficult. Often, an increased nutritionaldelivery of infant formula in this population resultsin elevated potassium exposure. Potassium resin-binders such as Kayexalate may be necessary, eitheras an oral medication or as a way to deplete thepotassium in a formula and normalize the serumpotassium of a patient.6–8 In many patients, thisis well-tolerated, yet in some, the vehicle in whichKayexalate is contained can cause diarrhea witha risk of malabsorption, feeding-tube obstruction,and the binding of other cations, includingcalcium and magnesium.6–8,10,11

Many programs use daily growth hormone toenhance growth. This method was shown to bevery effective, yet adequate nutrition is necessaryto maximize growth. Growth hormone shouldnever be used as a substitute for maximum nutri-tion. Although growth hormone is widelypromoted and prescribed by many healthcareproviders, it is often not accepted by familiesbecause of the daily injections.

Anuric and polyuric infants have differentnutritional requirements. Both these subsets ofinfants require adequate nutrition to maximizegrowth. Those who are polyuric may be given,and maintained on, a diluted formula and preemp-tively transplanted, never requiring dialysis. How-ever, it is important to monitor the amount offeeds being delivered to polyuric infants. Even

A

-2-1.5

-1-0.5

00.5

11.5

2

Infant Formula Adult Formula

Time

Wei

ght

Z s

core

**

B

-3-2.5

-2-1.5

-1-0.5

00.5

1

Infant Formula Adult Formula

Time

Hei

ght

Z s

core

**

C

-3-2.5

-2-1.5

-1-0.5

00.5

1

Infant Formula Adult Formula

Time

Hea

d C

ircu

mfe

renc

e Z

sco

re

*

Figure 2. Changes in (A)weight, (B) height, and (C)head-circumference z-scoresamong hyperkalemic infantswith CKD, after transitioningfrom infant to adult renalformula. *P , .05. **P , .01.

ADULT RENAL FORMULAS FOR HYPERKALEMIC CKD INFANTS 125

a low-potassium infant formula such as SimilacPM 60/40 may deliver excessive potassium, basedon an infant’s needs (Fig. 1). Those who are oligu-ric or anuric often require frequent dialysis, e.g.,daily peritoneal or hemodialysis, to offset the vol-ume related to the large-volume feeds that occurwith standard formulas. The use of hyperosmolaradult renal-formula prescriptions in oliguric in-fants facilitates the maximum delivery of nutritionwith reduced potassium exposure and minimalvolume.

The hyperkalemic infants described here dem-onstrated improved growth rates while receivingadult renal formula (Fig. 2). ‘‘Catch-up’’ or im-proved growth was attainable with an average en-ergy intake of 120% to 125% of dietary referenceintakes,12 but this requires further investigation.13

The infant and adult renal formulas involved fairlycomparable caloric and protein prescriptions, butlower potassium, calcium, and phosphorousprescriptions. The improvement in growth waslikely accounted for by a well-sustained deliveryof nutrition without excessive potassium exposureand, perhaps, slightly improved caloric deliverywith adult renal formula. With proper monitoring

of mineral intake and appropriate supplementa-tion, hyperkalemic infants can be nutritionallymaintained on adult renal formulas.

The use of adult formulas in infants with CKDwas not previously demonstrated, perhaps basedon concerns that these formulas may be specializedfor adults. We report that the use of adult renalformulas in infants with CKD is well-toleratedand effective in lowering potassium exposure,while achieving protein and caloric target goals.The use of adult renal formula was well-toleratedin hyperkalemic infants with CKD, but furtherinvestigation is required to determine the safetyof adult renal formulas in this patient population.

Conclusions

Adult renal formulas are low in minerals, andcan be used alone or else blended with other infantrenal formulas to manage the nutrition of hyper-kalemic infants with CKD. Because few infantrenal formulas exist, providers may need to becreative with adult renal formulas to deliver themaximum amount of nutrition without excessivepotassium exposure. A prospective study with

HOBBS ET AL126

a larger sample size is needed for further validationof the use and safety of adult renal formulas ininfants with CKD.

AcknowledgmentsD.J.H. is supported by an American Society of Nephrology

Student Scholar Grant. These data were presented as an

abstract at the 2006 University of Missouri Dialysis Meeting.

References

1. Kari JA, Gonzalez C, Ledermann SE, Shaw V, Rees L:

Outcome and growth of infants with severe chronic renal failure.

Kidney Int 57:1681-1687, 2000

2. Wingen AM, Mehls O: Nutrition in children with preter-

minal chronic renal failure. Myth or important therapeutic aid?

Pediatr Nephrol 17:111-120, 2002

3. Parekh RS, Flynn JT, Smoyer WE, et al: Improved growth in

young children with severe chronic renal insufficiency who use

specified nutritional therapy. J Am Soc Nephrol 12:2418-2426,

2001

4. Bunchman TE: Chronic dialysis in the infant less than 1 year

of age. Pediatr Nephrol 9(Suppl):S18-S22, 1995

5. Yaseen H: Nonoliguric hyperkalemia in neonates: a case-

controlled study. Am J Perinatol 26:185-189, 2009

6. Bunchman TE, Wood EG, Schenck MH, Weaver KA,

Klein BL, Lynch RE: Pretreatment of formula with sodium

polystyrene sulfonate to reduce dietary potassium intake. Pediatr

Nephrol 5:29-32, 1991

7. Fassinger N, Dabbagh S, Mukhopadhyay S, Lee DY: Mineral

content of infant formula after treatment with sodium polysterene

sulfonate or calcium polystyrene sulfonate. Adv Perit Dial 14:

274-277, 1998

8. Rivard AL, Raup SM, Beilman GJ: Sodium polysterene

sulfonate used to reduce the potassium content of a high-protein

enteral formula: a quantitative analysis. J Parenter Enteral Nutr 28:

76-78, 2004

9. Carey WA, Talley LI, Sehring SA, Jaskula JM, Mathias RS:

Outcomes of dialysis initiated during the neonatal period for

treatment of end-stage renal disease: a North American Pediatric

Renal Trials and Collaborative Studies special analysis. Pediatrics

119:e468-e473, 2007

10. Scherr L, Ogden DA, Mead AW, Spritz N, Rubin AL:

Management of hyperkalemia with a cation-exchange resin. N

Engl J Med 264:115-119, 1961

11. Townsend CM Jr, Remmers AR Jr, Sarles HE, Fish JC:

Intestinal obstruction from medication bezoar in patients with

renal failure. N Engl J Med 288:1058-1059, 1973

12. Ledermann SE, Shaw V, Trompeter RS: Long-term enteral

nutrition in infants and young children with chronic renal failure.

Pediatr Nephrol 13:870-875, 1999

13. Reed EE, Roy LP, Gaskin KJ, Knight JF: Nutritional

intervention and growth in children with chronic renal failure.

J Ren Nutr 8:122-126, 1998