ORIGINAL  
Niger J Paed 2013; 40 (1): 75 - 78  
Ogunkunle OO  
Erythrocyte indices of iron status in  
children with cyanotic congenital  
heart disease at the University  
College Hospital, Ibadan.  
DOI:http://dx.doi.org/10.4314/njp.v40i1.14  
Accepted: 30th July 2012  
Abstract Background Iron (Fe) defi-  
ciency is a known feature of cyanotic  
congenital heart disease (CCHD) and  
may worsen symptoms. The preva-  
lence of iron deficiency among chil-  
dren with CCHD at the University  
College Hospital (UCH), Ibadan is  
unknown. Erythrocyte indices of iron  
status are easier and less expensive to  
determine than serum iron, serum  
ferritin and total iron binding capac-  
ity, which are the standard tests of  
iron deficiency.  
Objectives: To examine the erythro-  
cyte indices of iron status in children  
with CCHD in UCH, and determine  
the prevalence of iron deficiency  
among such patients, by comparing  
the values obtained with established  
reference values.  
using a Sysmex 1000X1 Coulter  
counter, were compared with stan-  
dard reference values.  
Ogunkunle OO  
(
)
Department of Paediatrics  
College of Medicine,  
University College Hospital  
Ibadan, Nigeria.  
Email :ooogunkunle2004@yahoo.co.uk  
oogunkunle@comui.edu.ng  
Tel: +234-803-326-6909  
Results: Mean+SD values obtained  
were – PCV: 58.6+11.6%. MCV:  
3
80.7+12.1 µm , MCH: 25.9+9.5g/  
dl, MCHC: 30.9+4.1 and RDW:  
20.5.5+12.6%.  
Lower-than-normal values for  
MCV, MCH and MCHC were  
found in 33.5%, 42.5% and 72.5%  
of patients, respectively, while  
77.5% had higher-than-normal val-  
ues for RDW. However, using the  
criteria based on a combination of  
RDW and MCV, 35% of patients  
were iron deficient.  
Conclusion: A large proportion of  
Nigerian children with CCHD ap-  
pear to be iron deficient and are  
therefore likely to benefit from rou-  
tine iron therapy.  
Subjects and Methods: The packed  
cell volume (PCV), haemoglobin  
(
(
bin concentration (MCHC) and red  
cell distribution width (RDW) of 40  
children with CCHD, determined  
Hb), mean corpuscular volume  
MCV), mean corpuscular haemoglo-  
Key words: Cyanotic Congenital  
Heart Disease; Erythrocyte indices;  
Iron deficiency.  
Introduction  
definitive, is often prolonged for logistic or technical  
reasons. Iron therapy might benefit some of these pa-  
tients, particularly those in whom delays between diag-  
nosis and surgery may be inevitable because of other  
contingencies. A study of the iron status of children with  
CCHD was therefore thought to be germane, in that re-  
sults of the study would stimulate the formulation of  
guidelines as to the need or otherwise for iron therapy in  
patients with CCHD in general, and Fallot’s tetralogy in  
particular.  
Fallot’s tetralogy is the commonest cyanotic congenital  
heart disease (CCHD) worldwide. It is characterised by  
cyanosis of variable severity, associated with symptoms  
such as decreased effort tolerance, squatting, hyper-  
cyanotic spells, and in severely polycythaemic patients,  
bleeding diatheses and cerebrovascular events1,.2Iron (Fe)  
deficiency is known to be a feature of CCHD and may  
worsen symptoms. Iron therapy is therefore recom-  
mended for those who demonstrate this feature. The iron  
status of children with CCHD seen at the University  
College Hospital (UCH), Ibadan, has never been stud-  
ied. Iron therapy is not routinely administered to such  
children at the UCH. Many are extremely polycythae-  
mic, by virtue of either the severity, or the chronicity of  
their hypoxia, together with the fact that the time inter-  
val between diagnosis and surgery, whether palliative or  
Although determination of serum iron, serum ferritin  
and total iron binding capacity are the standard tests of  
iron deficiency, they are expensive and not routinely  
available. We therefore decided to use erythrocyte indi-  
cators of iron status as a starting point.  
7
6
Objectives  
Table 2: Mean age and weight of study patients  
The study aimed to:  
Male (23)  
Mean  
Female (17)  
p
1
.
Examine the erythrocyte indices of iron status in  
children with CCHD in UCH,  
SD  
Mean  
SD  
Mean Age  
(months)  
67.5  
46.4  
54.3  
43.9  
0.402  
2
.
Determine the prevalence of iron deficiency among  
such patients, by comparing the values obtained in  
one with established reference values.  
Mean weight (kg) 15.6  
4.3  
11.9  
9.0  
0.218S  
Fallot’s tetralogy formed the majority - 36 (90 %) of the  
patients, followed by Tricuspid atresia (TA) - 3  
(
7.5%).and Transposition of the Great Arteries (TGA) -  
Materials and methods  
1 (2.5%).  
The patients’ haematological profiles are depicted in  
Table 3  
Forty patients of the Paediatric Cardiology Unit of the  
UCH, Ibadan with a diagnosis of CCHD whose haema-  
tological data were complete were recruited into the  
study. Each patient had undergone a thorough clinical  
evaluation with special reference to the cardiovascular  
system (CVS), along with chest radiography, electrocar-  
diography and 2-dimensional (2-D) echocardiography,  
in order to establish the specific diagnosis. Their packed  
cell volume (PCV), haemoglobin (Hb), mean corpuscu-  
lar volume (MCV), mean corpuscular haemoglobin con-  
centration (MCHC) and red cell distribution width  
Table 3: Haematological profile of study patients  
Mean  
SD  
Median  
Mini-  
mum  
Maximum  
Haematocrit (%)  
Haemoglobin (g)  
Mean corpuscular  
58.6  
17.0  
80.7  
11.6  
4.0  
12.1  
59.0  
16.9  
80.0  
29.0  
7.2  
59.0  
85.0  
22.9  
101.0  
3
volume (µ m )  
Mean corpuscular  
haemoglobin (pg/cell)  
Mean corpuscular  
haemoglobin concen-  
tration (g/dl)  
25.9  
30.9  
9.5  
4.1  
23.8  
29.9  
16.7  
26.4  
74.3  
45.6  
(
Coulter counter. Each patient’s Hb genotype was also  
determined. Normal reference ranges for each parame-  
RDW) were determined using a a Sysmex 1000XI  
Table 4 shows that the frequencies of patients with  
values suggestive of Fe deficiency in each parameter  
were: MCV 37.5%, MCH 42.5%, MCHC 72.5%, and  
RDW 77.5%.  
3
ter were obtained from table 1, (adapted from Pesce. )  
Patients were adjudged to be iron deficient according to  
criteria combining the use of `MCV and RDW, ie if both  
the MCV was lower than normal, and RDW was higher  
Table 4: Distribution of patients’ haematological parameters  
4
than normal for the age .  
Patients’ values  
3
Low  
N
Normal  
High  
N
Table 1: Reference ranges for haematological tests.  
%
N
%
%
Age  
1-  
>14days  
>28days –  
5years  
>5years  
Haematocrit (%)  
Haemoglogbin (g)  
2
7
15  
5.8  
17.5  
37.5  
6
7
24  
15.0  
17.5  
60.0  
32  
26  
1
80.0  
65.0  
2.5  
1
4days  
Mean corpuscular volume  
Haematocrit (%)  
48–65  
14.5–  
28–42  
35–45  
35–45  
3
(
µ m )  
Haemoglogbin (g)  
9.0–14.0  
11.5–15.5  
11.5–15.5  
Mean corpuscular haemo-  
globin (pg/cell)  
Mean corpuscular haemo-  
globin concentration (g/dl)  
Red cell distribution width  
17  
29  
0
42.5  
72.5  
0.0  
20  
11  
9
50.0  
27.5  
22.5  
3
7.5  
2
2.5  
Mean corpuscular volume  
95–121  
70–86  
28–40  
70–86  
24–30  
77–95  
25–33  
0
0.0  
3
(µ m )  
Mean corpuscular haemo-  
globin (pg/cell)  
28–40  
31  
77.5  
(%)  
Mean corpuscular haemo-  
globin concentration (g/dl)  
28–38  
29–37  
30–36  
31–37  
Figures in bold type represent the percentages of patients with values  
suggestive of iron deficiency  
Red cell distribution width  
11 - 14.0  
11- 14.0  
11 - 14.0  
11 - 14.0  
(
%)  
However Table 5 shows that using the classification  
based on RDW and MCV by Bessman et al, which is  
the criterion adopted for this study, only 35% of the pa-  
tients met the criteria for iron deficiency.  
4
Data Handling  
The data were entered into an Excel spread-sheet. and  
analysed using SPSS 17.0 for Windows (SPSS Inc., Chi-  
cago, USA, 2010). Ranges, means and standard devia-  
tions were computed and compared with standard refer-  
ence values using the Students t test. The level of sig-  
nificance was taken as p<0.05.  
Table 5:Distribution of patients by MCV and RDW (indices  
of iron deficiency)  
Mean  
Red cell distribution width (%) Total  
corpuscu-  
Normal  
High  
N
lar volume  
N
% of all  
% of all  
patients  
N
% of all  
patients  
3
(
µm )  
patients  
Low  
Normal  
High  
1
7
1
9
2.5  
17.5  
2.5  
14 35.0  
17 42.5  
15  
24  
1
37.5  
60.0  
2.5  
Results  
0
0.0  
There were 23 males and 17 females and their ages  
ranged from 1 to 162 (median = 48) months. Table 2  
shows that the mean ages and weights of the males did not  
differ significantly from those of the females.  
Total  
22.5  
31 77.5  
40  
100.0  
4
Using the classification based on RDW and MCV from the above  
table 35.0% of the patients met the criteria for iron deficiency.  
7
7
Table 6 shows that 40.6% of patients who had a high  
PCV were also iron deficient, using the criteria of Bess-  
man et al , whereas none of patients with PCVs within  
haematocrit, haemoglobin concentration, MCV, MCHC  
and peripheral blood film examination are easy to per-  
form, relatively inexpensive and are e,f9fective in identi-  
4
1
the normal range, were iron deficient.  
fying iron deficiency when present. These methods  
were employed in this study and in the absence of more  
expensive tests like serum transferrin and serum ferritin,  
14 (35%) of the 40 children with CCHD with iron defi-  
ciency were identified.  
Table 6: Relationship between haematocrit level and  
presence of iron deficiency  
Haematocrit  
Iron defi-  
ciency  
Absent  
Iron defi-  
ciency  
Present  
Total  
The prevalence obtained in this study is similar to the  
37% prevalence reported by Kaemmerer, et al in 52  
7
N
%
N
%
N
2
%
German adults with CCHD. The figure is however much  
higher than the 16.9% quoted in anoth2er report from  
Kenya among 112 children with CCHD. The findings  
in this study are therefore consistent with previous re-  
ports showing that iron deficiency is a common feature  
in patients with CCHD. Notably, iron deficiency was  
present in 40.6% of children in the present study with  
high PCV levels but in none of the 6 patients whose  
PCVs were normal. This proportion is high enough for  
concern and might justify a practice of instituting judi-  
cious iron therapy in patients with high PCVs , on the  
assumption that deficiency is likely to be present.  
Low  
1
50.0  
1
50.0  
100.0  
Normal  
High  
6
100.0  
59.4  
0
0.0  
6
100.0  
100.0  
19  
13  
40.6  
32  
Total  
26  
65.0  
14  
35.0  
40  
100.0  
Chi square = 0.271, p = 0.603  
Discussion  
CCHD is known to be associated with a reduction in  
oxygen delivery to the tissues. Iron deficiency in CCHD  
has been shown to be associated w0ith a further reduction  
The subjects of this study were majorly patients with  
Fallot’s tetralogy, which is to be expected, being the  
most common CCHD. The apparent ‘under-  
representation’ of TGA and TA, though indeed known  
to be much less common than Fallot’s tetralogy, may be  
because some whose data were not complete were ex-  
cluded from analysis.  
1
in oxygen delivery to the tissues. This further worsens  
the tissue hypoxaemia in individuals with CCHD. Clear  
recommendations for the supplementation of iron in  
children with CCHD are lacking. Our findings suggest  
that iron deficiency is common in Nigerian children with  
CCHD. Further studies using the gold-standard tests  
would still be required in order to verify the figures ob-  
tained in this study. In the interim, it is recommended  
that all children with CCHD should have routine assess-  
ment of the simple haematological indices for prompt  
detection and judicious treatment of iron deficiency.  
Children with CCHD often experience severe hypoxae-  
mia which may cause damage to the organs, particularly;  
the lungs, kidneys, musculoskeletal system and the cen-  
tral nervous system (CNS). A major compensatory  
mechanism to combat tissue hypoxaemia is secondary  
erythro, p6 oiesis with consequent increase in the red cell  
5
mass. This study showed that 32 (80.0%) of the cases  
had high haematocrit values. Iron deficiency is reported  
to be common in individuals with 2C,7,C8HD even in the  
Conflict of Interest: None  
Funding: None  
presence of high haematocrit levels.  
These groups of  
children are often assumed not to be iron deficient be-  
cause of the elevated red cell mass.  
Acknowledgement  
The use of simple red cell indices has been shown to be  
effective in identifying iron deficie1ncy in individuals  
suspected to be deficient in iron. Measurement of  
I wish to acknowledge Dr AE Orimadegun for assis-  
tance in the preparation of the manuscript.  
References  
1
2
.
.
Onur CB, Sipahi T, Tavil B,  
Karademir S, Yoney A. Diagnos-  
ing iron deficiency in cyanotic  
heart disease. Indian J Pediatr  
3. Pesce MA. Reference Ranges for  
5. O’Brien P, Smith PA. Chronic  
hypoxemia in children with cya-  
notic heart disease. Crit Care Nurs  
Clin North Am 1994; 6:215-6  
6. West DW, Scheel JN, Stover R,  
Kan J, DeAngelis C. Iron defi-  
ciency in children with cyanotic  
congenital heart disease. J Pediatr  
1990; 117: 266-8  
Laboratory Tests and Procedures.  
In: Kliegman RM, Behrman RE,  
Jenson HB, Stanton BF (eds) Nthel-  
son Textbook of Pediatrics, 18  
ed. Philadelphia : Saunders,  
2
003; 70: 29-31  
Lang’o MO, Githanga JN, Yuko-  
Joni CA. Prevalence of iron defi-  
cieny in children with cyanotic  
heart disease at Kenyatta National  
Hospital and Mater Hospital, Nai-  
robi. East Afr Med J 2009; 86:  
S47-51  
2007:2939-54  
4. Bessman JD, Gilmer PR Jr, Gard-  
ner FH. Improved classification of  
anemias by MCV and RDW. Am J  
ClinPathol1983; 8:322-6.  
7
8
7
.
Kaemmerer H, Fratz S, Braun SL,  
et al. Erythrocyte indexes, iron  
metabolism, and hyperhomocys-  
teinemia in adults with cyanotic  
congenital heart disease. Am J  
Cardiol 2004; 94: 825-8  
8. Broberg CS, Bax BE, Okonko DO,  
et al. Blood viscosity and its rela-  
tionship to iron deficiency, symp-  
toms and exercise capacity in  
adults with cyanotic congenital  
heart disease. J Am Coll Cardiol  
9. Olcay L, Ozer S, Gurgey A, et al.  
Parameters of iron deficiency in  
children with cyanotic congenital  
heart disease. PediatrCardiol  
1996; 17: 150-4.  
10. Gidding SS, Stockman JA. Effect  
of iron deficiency on tissue oxygen  
delivery in cyanotic congenital  
heart disease. Am J Cardiol 1988;  
2
006; 48: 356-65  
6
1: 605-7