Prevalence of β-haemoglobinopathies in Eastern India and development of a novel formula for carrier detection

Beta thalassemia is the commonest inherited monogenic disorder and India forms a major part of the thalassemia belt in the world. Effective screening programmes and proper prenatal diagnosis are the only ways to eradicate the disease. Haemoglobin high-pressure liquid chromatography (HPLC) is the screening method employed for detection of thalassemia carriers. The aim of this paper was to investigate the prevalence and demographic profiles of thalassemia carriers in Eastern India. Haemogram data was used to develop a novel haematological index for thalassemia carrier detection. This was a retrospective analysis of data collected from 21,695 individuals at thalassemia screening camps. The prevalence of the common hemoglobinopathies and their regional variations were noted. Using stepwise discriminant analysis, RBC indices were analysed to develop a novel formula to help distinguish β-thalassemia carriers from normal individuals. Out of the total population analysed, β-hemoglobinopathy carrier prevalence was around 10%. HbE was the commonest hemoglobinopathy in the region. There was no difference in the prevalence rates of thalassemia carriers amongst religious communities. The formula generated was expressed as outcome = RBCx6.59 + MCHx0.527 − (HCTx0.782 + MCHCx0.395 + RDWx0.02 + 1.365). Any integer value more than 0.5 indicated the probability of carrier status while a value less than 0.5 was normal. The formula had a negative predictive value of > 96% and an accuracy of 89%. This study provides an audit of the common β-hemoglobinopathies in Eastern India. The regional variations and prevalence of hemoglobinopathies highlighted here may guide public health efforts. The formula generated from RBC indices can be used to screen individuals prior to HPLC testing, thereby reducing overall costs of thalassemia screening in the country.