Background and Objectives: Vaso-occlusive crisis, a common clinical presentation of sickle cell disease is a major cause of morbidity. It has been observed in some cases of sickle cell trait also. Hydroxyurea exerts beneficial effect primarily by increasing fetal hemoglobin and also through other mechanisms. The Arabian-Indian haplotype of Hemoglobin S is associated with moderate form of disease and high fetal hemoglobin level. This study was conducted to assess the clinical and hematological response of homozygous and heterozygous cases of Hemoglobin S to hydroxyurea therapy. The adverse reactions to the drug were also observed.

Material and Methods: The study, an interventional case series, was conducted at a teaching hospital in Central India during January 2013 to December 2014.A total of 54 cases satisfying eligibility criteria were recruited. 9 cases (2 due to severe reaction and 7 due to poor compliance) were excluded. Thus study comprised of 45 cases of sickle cell disease (36 homozygous and 9 heterozygous). Detailed clinical examination, baseline investigations and HPLC were performed. Cases received 10 mg/kg/ day of Hydroxyurea and were followed up weekly in sickle-cell opd for compliance, effectiveness and adverse reactions. At the end of one year of hydroxyurea therapy, baseline investigations and HPLC were repeated. Appropriate statistical analysis was done using STATA version 13.1.

Results: Statistically significant clinical response, namely decrease in the frequency of vaso-occlusive crises and duration of hospitalization and improvement of clinical score was observed (p<0.0001)in homozygous and heterozygous cases of sickle cell disease. Statistically significant hematological response (p<0.0001) namely, increase in  hemoglobin, mean corpuscular volume of red cell and fetal hemoglobin level, decrease in total leukocyte count was observed in homozygous and heterozygous cases of sickle cell disease. Hydroxyurea was well tolerated.

Conclusion: Hydroxyurea is effective in homozygous cases of sickle cell disease. Hydroxyurea is effective in HPLC proven heterozygous cases of sickle cell; however, detailed hemoglobin structure and genetic studies recruiting larger number of these cases is recommended. Hydroxyurea is effective despite high level of fetal hemoglobin. Hydroxyurea is well tolerated and must be administered with regular monitoring.

Keywords: Sickle cell disease (SS), sickle cell trait (AS), hydroxyurea, fetal hemoglobin, clinical response, hematological response, adverse reactions.

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Dr Mrinalini Hardas

Assistant Professor, Dept.of. Medicine IGGMC, Nagpur, India