Serum Ferritin Levels of Steady State Sickle Cell Anaemia Children in Enugu Southeast Nigeria

Background: Serum ferritin(SF), an indicator of body iron stores may be elevated for reasons such as inflammation, chronic haemolysis, and multiple transfusions which all occur frequently in sickle cell anaemia (SCA) patients. Serum ferritin values above 30 µg/dl(300ng/ml) have been said to signify an increase in iron stores. Hyperferritinemia up to ≥500 ng/ml predisposes an individual to haemachromatosis / iron overload. SF values ≥500 ng/ml have been found detectable after twenty blood transfusions and is an indication for iron chelation therapy. The aim of this study is to ascertain the prevalence of elevated SF and identify associated risk factors in a set of Southeast Nigerian SCA children in a steady state.

Methods: This study regarded elevated iron stores as SF level ≥ 200 ng/ml and classified this as mild (200 to 500ng/ml), moderate (>500 to 1000ng/ml) and severe(>1000ng/ml). Normal values are between (10 and 150 ng/ml) and ≥500 ng/ml as a predisposition to iron overload. SCA children aged 10 months to 17 years in steady state and without notable confounding variables were recruited. Participants were classified into socio-economic classes (SEC), according to Oyedeji. The protocols of research ethics were duly followed. SF was assayed by the enzyme immunoassay using a Mini vidas® device (BioMérieux, France). Standard specimen handling and laboratory operating procedures and the machine and reagent manufacturers’ guidelines were adhered to. The Chi Square test or Fisher Exact test were used to compare the categorical variables while the Student’s t-tests was used for the numerical variables. The associated risk factors were identified using univariate analysis at 5% level of significance (p < 0.05).

Results: Participants were 27 male and 35 female SCA patients who were in steady state. Their mean age was 9.06±4.97 years and 50% were in middle SEC.(50.0%). Mean SF was 517.53±696.78, majority 27(43.5%) had mildly elevated SF levels, 7(11.3%) markedly elevated levels, 17(27.4%) had normal levels but no participant had lower than normal SF levels. Majority (50%) of the participants had haemoglobin F (HbF) levels below 10 while 67.7% had haemoglobin S (HbS) levels above 80%. There was no correlation between SF and HbS, haemoglobin concentration [Hb] or packed cell volume (PCV) but a significant negative correlation existed between SF and and HbF. On comparing the SF of all participants, no statistically significant differences existed between the sexes, SEC, those with frequent (≥3) crises or periodic blood transfusions (≥3) annually, [all (p = >0.05)]. For participants with elevated SF (Table 6), SF levels were more markedly elevated in females, among the lower SEC, and among those with frequent crises and blood transfusion but these differences were also not statistically significant.

Conclusions: In steady state SCA children on periodic blood transfusion, serum ferritin is mostly mildly elevated despite age, gender, socioeconomic class and HbS levels. Low HbF levels may be a risk for elevated serum ferritin.