Role of Absolute Reticulocyte Count in the Assessment of Renal Function and Erythropoietin Response in Adults with Sickle Cell Anemia Seen at the Lagos University Teaching Hospital
Date
2018
Authors
Anyanwu, U
Ogbenna, A
Journal Title
Journal ISSN
Volume Title
Publisher
American Society for Clinical Pathology
Abstract
Objectives: To compare absolute reticulocyte count (ARC)
and serum erythropoietin (EPO) to established markers
of renal impairment (eGFR-creatinine and cystatin C) in
steady-state adult SCA patients and HbAA control.
Methods: This was a cross-sectional study conducted in
LUTH. Eighty participants comprising 40 SCA patients
and 40 HbAA who met the inclusion criteria were
recruited. Reticulocyte counts and automated FBC were
done and ARC was calculated. Serum creatinine was
done by Jaffe’s method while EPO and cystatin C assays
were done using ELISA techniques. Creatinine- and cystatin
C–based eGFR was estimated using the CKD-EPI
formula. Participants with ARC <250 × 109/L with concomitant
Hb <9 g/dL were reinvited after 4 weeks, and
those who had chronic relative reticulocytopenia (ChRR)
were noted. Data were analyzed with IBM SPSS version
21. P value was set at .05.
Results: There was no difference between the study
(n = 40) and the control (n = 40) groups in median ARC
(P = .260) or mean eGFR-creatinine (P = .054). There was
a difference between study and control groups in median
EPO levels (98.45 vs 16.43 U/L; P < .001) and mean
eGFR-cystatin C (99.0 ± 35.12 vs 120.78 ± 21.38 mL/
min/1.73 m2, P = .001). ARC correlated with EPO
(r = 0.716, P = .009) in SCA patients with impaired
eGFR-cystatin C. There was no correlation between
ARC and EPO in SCA patients with normal renal status
(r = 0.327, P = .09). There was a difference between
the SCA group with ChRR (n = 8) and those without
ChRR (n = 32) in median ARC (54.30 [34.75–62.75] vs 103.0 [62.75–182.25] × 109/L, P = .002), median EPO
(29.30 [17.68–35.65] vs 103.45 [89.99–116.18] U/L, P
< .001), and mean eGFR-cystatin (51.75 ± 23.11 vs
112.22 ± 24.27 mL/min/1.73 m2, P < .001). ChRR was
more sensitive (63.6%) than eGFR-creatinine (18.2%)
with similar specificity (96.6%) in detecting renal impairment
in SCA patients. Conclusion: Our study identified ARC and ChRR as
potential routine biomarkers for renal damage and suggests
longitudinal validation of these biomarkers for early
detection of renal insufficiency so that therapeutic interventions
can be applied before the renal damage becomes
irreversible.
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Citation
Anyanwu, U. and Ogbenna, A. (2018). Role of Absolute Reticulocyte Count in the Assessment of Renal Function and Erythropoietin Response in Adults with Sickle Cell Anemia Seen at the Lagos University Teaching Hospital. American Society for Clinical Pathology, 150(1), S114-S115.