Cystatin C as an Early Marker of Glomerular Dysfunction in Children with Beta Thalassemia Major

Background and aim of work: Reports investigating renal dysfunction in beta
thalassemia major (β-TM) patients have been limited in number, mainly studying
adult patients. Additionally, most of them had not assessed early markers of
glomerular dysfunction such as cystatin C. Early identification of patients at high risk
is of great importance as it may allow specific measures to be taken to delay renal
impairment. The present work aimed to estimate the frequency of glomerular
dysfunction in children with β-TM by using different markers and to correlate these
markers to serum ferritin and iron chelation therapy. Patients and Methods: The
study included one hundred patients with β-TM (Group Ι) which was subdivided into;
groups: I-a included 62 patients (62%) with iron chelation therapy (deferoxamine)
and group I-b included 38 patients (38%) without iron chelation therapy and Group
II (control group) included fifty apparently healthy volunteers age and sex matched to
the diseased groups. Members of the two groups were subjected to; history taking,
clinical examination and laboratory investigations including determination of: Serum
ferritin, albumin/creatinine ratio in urine, eGFR by both Schwartz formula and
creatinine clearance; blood urea and serum creatinine and finally serum cystatin C.
Results: Group I showed significant higher levels of Cystatin C, serum creatinine,
serum ferritin, albumin /creatinine ratio in urine than group II. Furthermore, they
had significantly lower eGFR and creatinine clearance than group II (p<0.05).
Moreover, group Ι-a had significant lower eGFR and creatinine clearance than group
I-b. Also, cystatin C had highly significant strong negative correlation with eGFR and
creatinine clearance and significant strong positive correlation with serum ferritin.
Finally, cystatin C had higher sensitivity and specificity than serum creatinine and
creatinine clearance for small changes in GFR. Conclusion: Glomerular dysfunction
in β-TM is not a rare complication so, the use of early markers such as cystatin C is
useful for the early detection of small changes in GFR. Periodic renal assessment of
those patients is mandatory where many of them may had hidden renal affection