CORRELATION OF SERUM AND URINE SIALIC ACID LEVELS IN THE COURSE OF RENAL INSUFFICIENCY IN SICKLE CELL ANAEMIA PATIENTS

Abstract

BACKGROUND: Renal manifestations of sickle cell anaemia range from
functional abnormalities to gross anatomic alterations of the kidneys. As
people with SCA grow older, the kidneys may progress to end stage renal
disease (ESRD) if proper monitoring of renal function is not done.
AIM: The aim of this study is to assess the status of serum and urinary
sialic acid in sickle cell anaemia patients and correlate with plasma urea
and creatinine in patients with and without renal insufficiency.
METHODOLOGY:Venous blood and fresh urine samples were collected
from participants at about 08:00hrs on the day of their appointment .
The standard Ehrlich method was used in analysis of serum and urinary
sialic acid .The Lowry method was used for analysis of urine albumin ,
the modified Jaffe method for plasma and urinary creatinine and the
Urease Berthelot method for plasma urea.
RESULTS: Ninety eight (98) patients consisting of 68 SCA patients and 30
controls (non-SCA patients) participated in the study. The mean age was

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28.35 ± 3.46 years for SCA patients and 33.12 ± 6.24 years for controls;
withmost of the SCA patientsbeing females (M:F = 1 : 1.6). The SSA level
was 1.88 ± 7.92mmol/L for SCA patients and 1.93 ± 3.67mmol/L for
control. The SSA level was higher in SCA patients with microalbuminuria
(1.89 ± 0.48mmol/L) than in those with normoalbuminuria (1.86 ±
0.46mmol/L), but this was not significant (p=0.81). The mean USACR
was significantly lower (60.52 ± 18.57mmol/mol; p<0.001) for
controlsthan in SCA patients(169.39 ± 42.07mmol/mol).The mean SSA
was significantly higher (p=0.04) in controls (1.93 ±3.67mmol/L) than
inSCA patients in steady state (1.55 ± 0.17mmol/L) while the mean
USACR was significantly (p<0.001) higher in SCA patients in steady state
(111.47 ± 31.11mmol/mol) than in the control (60.52 ±
18.57mmol/mol). There were also positive correlation between USACR
and plasma urea (r=0.27, p=0.05), plasma creatinine (r=0.13, p=0.31),
ACR (r=0.43, p<0.001) and SSA (r=0.37, p<0.001).
CONCLUSION: SSA is low in SCA patients as a result of an increased loss
of sialic acid from haemolysed red blood cells. SSA is also higher in SCA
patients with microalbuminuria than in those with normoalbuminuria.

The mean USACR is higher in SCA patients and is positively correlated
with plasma urea and creatinine and ACR. Monitoring of serum and
urinary sialic acid in patients with sickle cell anaemia will be important
in detecting early onset of sickle cell nephropathy.