Disease-related complications and risk factors in hemoglobin H disease in a Thai multicenter registry.

Hemoglobin H (Hb H) disease is a prevalent hereditary hemolytic anemia worldwide. Clinical severity varies by genotype, particularly between deletional and non-deletional forms, as well as the presence of co-inherited Hb E. However, disease-related complications remain underreported. We analyzed a Thai multicenter registry of 1,298 patients with Hb H disease to evaluate disease-related complications and risk factors. Deletional Hb H disease accounted for 55.9% of cases, whereas 44.1% had non-deletional disease. Hb E co-inheritance was present in 253 patients (19.5%). Patients with non-deletional Hb H disease and co-inherited Hb E had lower hemoglobin, higher ferritin levels, and greater transfusion requirements. Gallstones, pulmonary hypertension, extramedullary hematopoiesis, osteoporosis, and fractures were more frequent in non-deletional Hb H disease. After adjustment, increasing age (AOR 1.5; 95% CI 1.3-1.6; p<0.001), non-deletional Hb H disease (AOR 2.3; 95% CI 1.5-3.5; p<0.001), and transfusion dependency (AOR 2.7; 95% CI 1.4-5.3; p=0.003) were independently associated with overall complications. Splenectomy showed a marginal association (AOR 2.0; 95% CI 0.9-4.2; p=0.06). Gallstones were independently associated with non-deletional Hb H disease, splenectomy, and higher ferritin levels. Hyperuricemia was independently associated with increasing age and higher hemoglobin levels. These findings support genotype-informed monitoring in Hb H disease.