Effect of α Thalassemia on the Severity of Malaria in Different Sickle Cell Genotypes in Indian Adults: A Hospital-Based Study.

There is a paucity of literature on the association of α-thalassemia, sickle-cell hemoglobin disorders, and malaria in India. This study aimed to understand the effect of α-thalassemia on the severity of malaria in adults with respect to sickle-cell genotypes. The study subjects were categorized into 'severe-malaria' and 'uncomplicated-malaria' and age-gender matched 'control' groups. Sickle-cell and α-thalassemia were investigated in all the recruited subjects. The effect of α-thalassemia on the severity of malaria was analyzed in HbAA and sickle-cell genotypes (HbAS and HbSS) separately. The prevalence of α-thalassemia in various groups ranged from 41.5% to 81.8%. The prevalence of α-thalassemia was lower (OR = 1.64;  0.0013) in severe malaria (41.5%) as compared to healthy controls (53.8%) with HbAA genotype. In contrast, in HbAS genotype, the prevalence of α-thalassemia was higher (OR = 4.11;  0.0002) in severe malaria (81.8%) compared to controls (52.2%). In severe malaria with HbAA genotype, there was a significantly higher hemoglobin level and low MCV and MCH level in patients with α-thalassemia compared to the normal α-globin genotype. Further, the incidence of cerebral malaria, hepatopathy, and mortality was lower in patients (HbAA) with α-thalassemia as compared to normal α-globin genotype (HbAA). In severe malaria with either HbAS or HbSS genotype, only a few parameters showed statistical differences with respect to α-thalassemia. Low prevalence of α-thalassemia in severe malaria with HbAA genotype compared to healthy controls with HbAA genotype indicates the protective effect of α-thalassemia against severe malaria. However, the high prevalence of α-thalassemia in patients with HbAS genotype depicts its interference in the protective effect of sickle-cell against severe malaria.