A Multicenter Retrospective Study of HbH in China Including 1421 Patients Over a 12-Year Timespan

Abstract

Background

Hemoglobin H (HbH) disease is a relatively common genetic disorder worldwide. However, the lack of long-term follow-up studies involving large patient cohorts has limited our understanding of its clinical features, disease progression, and outcomes.

Methods

We conducted a retrospective study of 1421 patients diagnosed with HbH disease who were admitted to six hospitals in the Guangxi Zhuang Autonomous Region, China, between 2010 and 2022. We analyzed hemoglobin levels and their association with different genotypes and ages. Key hematological parameters, serum ferritin levels, and visit frequency were compared between patients with HbH-constant spring (HbH-CS) and those with deletional HbH. Additionally, we assessed the survival status of 117 patients over 30 years of age and examined complications and causes of death in four patients who died during the study period.

Results

In the cohort, 73.0% of patients had HbH-CS, while 24.2% had deletional HbH. Patients with HbH-CS exhibited a significantly younger average age, lower mean and minimum hemoglobin (Hb) levels, and higher visit frequencies and serum ferritin levels compared with those with deletional HbH. Iron overload was common in HbH-CS patients, with a mean serum ferritin level of 1284 ± 1231 ng/mL (measured in 671 patients). Among the four deceased patients (aged 44.8 to 68.5 years), at least two deaths were attributed to severe anemia and related complications.

Conclusion

This study provides valuable insights into the natural history, clinical progression, and long-term outcomes of HbH disease in a large patient cohort over the past decade. It highlights key differences between HbH-CS and deletional HbH, particularly in terms of disease severity, iron overload, and survival outcomes.

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