ESTABLISHING A RELATIONSHIP BETWEEN SERUM HOMOCYSTEINE LEVELS AND DISEASE SEVERITY IN ADULTS WITH SICKLE CELL ANAEMIA IN LAGOS UNIVERSITY TEACHING HOSPITAL (LUTH), LAGOS, NIGERIA

Abstract

The aim of this study was to determine serum homocysteine levels in Nigerian adults
with sickle cell anaemia (SCA), evaluate the relationship between serum homocysteine and
folate and vitamin B12 levels as well as to assess the effects of homocysteine on sickle cell
disease (SCD) severity, frequency of painful (vaso-occlusive) crisis and markers of
haemolysis.
This was a cross-sectional study conducted on adult subjects with SCA in Lagos
University Teaching Hospital, Lagos, Nigeria; from December 2014 to April 2015.
Sickle cell anaemic subjects were recruited purposively from the adult haematology out
patient clinic and the emergency unit of the hospital. One hundred and ten (110)
participants consisting of 84 subjects with SCA and 26 Hb AA controls were recruited into
the study. Of subjects with SCA, 25 were in the steady state (Group A), 30 in vaso-occlusive
crisis (Group B) and 29 in hyperhaemolytic crisis (Group C). Serum homocysteine, folate
and vitamin B12 levels of all participants were determined using ELISA test kits. Full
blood count including red cell indices and reticulocyte count together with serum
bilirubin and lactate dehydrogenase (LDH) were determined. The statistical package for
social science software (SPSS) 2012, version 21 was used to assess the means and perform
correlation analysis. The level of statistical significance was defined as p – value ≤ 0.05.
The mean age of participants in the control group was 27.5 ± 6.6 years (14 males, 12
females), that of Group A was 24.9 ± 5.2 years (10 males, 15 females), Group B was 24.8
± 5.9 years (17 males, 13 females) and Group C was 24.9 ± 5.3 years (16 males, 13
females). There was no significant difference between the mean age of controls and that of
the subjects (Groups A, B and C had p-values of 0.116, 0.142 and 0.110 respectively).
The mean serum homocysteine level of group A (10.3 ± 2.3 µmol/L) and group B (11.9 ± 4.5
µmol/L) were not significantly different from that of controls (10.2 ± 2.9 µmol/L) but, Group
C (13.1 ± 5.5 µmol/L) was significantly higher (p < 0.01). In addition, the mean
serum homocysteine of Group C was significantly higher than that of Group A (p < 0.01).
The mean serum folate level of Group C (9.9 ± 5.5 nmol/L) was significantly lower than that
of controls (12.9 ± 6.8 nmol/L; p = 0.042), however, there was no demonstrable difference
in the mean serum folate level of Groups A and B (A = 11.8 ± 4.1 nmol/L, B = 12.7 ± 2.1
nmol/L) when compared with controls. The mean serum vitamin B12 level in each of the
three groups (A = 99.1 ± 30.3 pmol/L; B = 104.9 ± 51.2 pmol/L; C = 91.2 ± 38.5 pmol/L)
was not significantly different from that of controls (97.8 ± 29.5 pmol/L; p > 0.05). There
was a significant negative correlation between serum homocysteine level and serum folate
level in Groups B and C (r = – 0.705; p < 0.001 and r = – 0.747; p < 0.001) respectively.
There was no significant correlation between serum vitamin B12 and serum homocysteine
in each of the groups; (A= r -0.346; B = r -0.214; C = r -0.081; p > 0.05). The mean values
for markers of haemolysis for subjects were: reticulocyte production index (RPI) (A = 2.2 ±
1.1; B = 2.2 ± 1.1; C = 4.6 ± 1.0), absolute reticulocyte count (A = 198.3 ± 93.2 x 109/L;
B = 197.4 ± 83.9 x 109/L; C = 471 ± 103.5 x 109/L), LDH (A = 688.8 ± 238.5 U/L; B =
569.7 ± 325.1 U/L; C = 863.3 ± 98.0 U/L) and indirect bilirubin (A = 21.9 ± 23.1 mg/dl; B
= 31.1 ± 12.6 mg/dl; C = 47.9 ± 23.6 mg/dl). The mean disease severity score for subjects
in Group A was 3.0 ± 1.4. There was no significant correlation between serum
homocysteine and markers of haemolysis (RPI- r = -0.240; absolute reticulocyte count- r =
0.241; LDH- r = 0.016; indirect bilirubin- r = 0.145) and between serum homocysteine and
disease severity score (rs = 0.102) in Group A (p > 0.05). The mean value for severity of
VOC and frequency of VOC per year in Group B were 6.6 ± 1.4 and 2.5 ± 1.6
respectively. There was no significant correlation between serum homocysteine and
severity of VOC and between serum homocysteine frequency of painful crisis per year
in Group B (rs = 0.116; p > 0.05 and rs = 0.181; p > 0.05 respectively). There was no
significant difference in mean serum folate and mean serum homocysteine levels of
compliant subjects (A = folate -11.4 ± 4.7 nmol/L, homocysteine- 10.5 ± 2.5 µmol/L; B =
folate -12.8 ± 6.2 nmol/L, homocysteine- 13.4 ± 5.3 µmol/L; C = folate -10.3 ± 5.6
nmol/L, homocysteine- 11.0 ± 4.2 µmol/L) and non-compliant subjects (A = folate -11.9 ±
2.5 nmol/L, homocysteine- 9.8 ± 1.7 µmol/L; B = folate -12.6 ± 7.4 nmol/L,
homocysteine- 12.8 ± 5.7 µmol/L; C = folate -9.5 ± 5.7 nmol/L, homocysteine- 12.7 ± 4.8
µmol/L; p > 0.05).
This study demonstrated that the mean serum homocystene level in hyperhaemolytic crisis
was significantly higher when compared with those of the steady state and controls
respectively. However, the significant negative relationship between serum homocysteine
and serum folate in both vaso-occlussive and hyperhaemolytic crises was not mirrored in
the steady state. Therefore, the use of higher doses of folate supplement is being advocated
in subjects with these types of crises.

ESTABLISHING A RELATIONSHIP BETWEEN SERUM HOMOCYSTEINE LEVELS AND DISEASE SEVERITY IN ADULTS WITH SICKLE CELL ANAEMIA IN LAGOS UNIVERSITY TEACHING HOSPITAL (LUTH), LAGOS, NIGERIA