Influence of Hemoglobin E Trait on the Antimalarial Effect of Artemisinin Derivatives

To determine whether hemoglobin E trait influences the antimalarial effect of artemisinin derivatives, we retrospectively compared 32 case patients with hemoglobin E trait to 32 control patients who did not have hemoglobin E, β-thalassemia, glucose-6-phosphate dehydrogenase deficiency, or α-thalassemia trait on the basis of a mean corpuscular volume ⩾78 femtoliters. All patients were admitted to the Hospital for Tropical Diseases in Bangkok, Thailand, with acute falciparum malaria. Control patients were matched to case patients with hemoglobin E trait by treatment with artemisinin derivatives versus other antimalarial drugs, by ethnic group, and by parasite count. Among 38 patients treated with artemisinin derivatives, the presence of hemoglobin E trait was associated with significantly faster parasite clearance (2.9-fold; 95% confidence interval [CI], 1.4–6.3; P = .006). Among 26 patients treated only with other antimalarial drugs, hemoglobin E trait did not significantly enhance parasite clearance (hazards ratio, 1.1; 95% CI, 0.5–2.5; P = .8). Hemoglobin E trait may potentiate the antimalarial effect of artemisinin derivatives.