Hematologic Indices of Hemoglobin D Co-Inheritance with α and β Thalassemia: A Comparative Study of 202 Patients

To characterize the hematologic effects of hemoglobin D (HbD) alone and in the presence of co-inherited α- or β-thalassemia, and to quantify associations with anemia, microcytosis, and hypochromia relative to normal-CBC controls. This retrospective comparative study included 202 adults with molecularly confirmed HbD-Punjab, HbD only (n = 79), HbD plus β-thalassemia (n = 78), and HbD plus α-thalassemia (n = 45), and 100 normal-CBC controls. Hematologic indices were compared using Welch's one-way ANOVA or the Kruskal-Wallis test, with appropriate post hoc analyses. Case-control analyses evaluated anemia (Hb <12 g/dL), microcytosis (MCV <80 fL), and hypochromia (MCH <26 pg). A post hoc analysis used sex-specific anemia thresholds. WBC, RBC, Hb, MCV, MCH, HCT, and MCHC differed across the four groups (all p ≤ 0.002), whereas HCT did not (p = 0.523). HbD plus β-thalassemia had the lowest MCV (65.67 ± 6.85 fL) and MCH (21.12 ± 2.55 pg), which were significantly lower than in the HbD-only and HbD plus α-thalassemia groups (all p < 0.01). Hemoglobin did not differ significantly among the three HbD subgroups. Compared with controls, anemia was associated with HbD only (OR = 8.3, 95% CI 3.22-25.74), HbD plus β-thalassemia (OR = 11.9, 95% CI 4.68-36.59), and HbD plus α-thalassemia (OR = 11.5, 95% CI 4.16-37.68). Microcytosis and hypochromia also differed significantly between HbD groups and controls (Fisher's exact p < 0.001). Sex-specific sensitivity analyses preserved all associations with anemia. β-Thalassemia co-inheritance produced the most pronounced microcytic-hypochromic phenotype, whereas α-thalassemia had a less pronounced effect. HbD alone was associated with relatively mild changes in red-cell indices, but co-inherited thalassemia, particularly β-thalassemia, substantially altered the hematologic phenotype. Integrated hematologic, electrophoretic, and molecular assessment is important for accurate classification.