Beneficial Effect of Low Fixed Dose of Hydroxyurea in Vaso-occlusive Crisis and Transfusion Requirements in Adult HbSS Patients: A Prospective Study in a Tertiary Care Center.

Abstract

Significant reduction in morbidity and mortality have been documented in patients with sickle cell disease (HbSS) by most of the studies using hydroxyurea at a dose of 25-35mg/kg/day or maximum tolerated dose. But toxicities, need for frequent monitoring, compliance and cost are important hurdles particularly in Indian set up. We undertook this study to find out the efficacy, safety compliance rate of low fixed dose of hydroxyurea (10mg/kg/day) in patients presenting to our hospital and its impact on clinical profile and laboratory parameters. A cohort of 128 (82 males, 46 females) confirmed HbSS cases (each >18years age, vaso-occlusive crisis >2/years and/ or rate of transfusion 1-2units/month) with no disease related end organ damage were assessed prospectively between 2013 and 2016. They were started on 10mg/kg/day hydroxyurea along with other supportive care and followed up monthly for 1year. Clinical and laboratory parameters before and after therapy were reviewed and compared. In 92% of cases presenting with repeated vaso-occlusive crisis, VOC disappeared completely during follow up and in 8% we found significant reduction in severity as well as frequency of attacks (p<0.01). Again in 87%, no further transfusion was required during follow up and in 13%, it further reduced the rate of transfusion (p<0.01). The median time of response for VOC was 3months and in transfusion requirement was 5months. There was also significant reduction in S.Billirubin, S.LDH, disease related complications and rate of hospitalisation with significant improvement in Hb, MCV, and MCH. There is insignificant increase in HbF with median (1.5-2.4)% and in 5 cases >5%. We did not find any remarkable adverse effect of the drug during the study period. Low fixed dose hydroxyurea (10mg/kg/day) is beneficial in reducing the vaso-occlusive crisis and transfusion requirement in adult HbSS Patients (Arab-Indian Haplotype). It is safe, suitable and is a effective mode of treatment in resource poor setting like India.