Clinical Features and Morbidities of Hb H Disease in Taiwan

Introduction Patients with non-transfusion-dependent thalassemia experience a wide array of clinical complications despite their independence from frequent, regular red blood cell transfusions. They have the higher incidence of osteoporosis, extramedullary hematopoeisis (EMH), hypogonadism, cholelithiasis, thromboembolic disease, pulmonary hypertension, silent cerebral ischemia, and leg ulcers. Thalassemia is highly prevalent in Taiwan and Hb H disease is predominant. But limited data are available about clinical features and morbidities. Here, we studied clinical features and morbidities in Taiwanese patients with Hb H disease.

Methods & Results We collected 90 patients with Hb H disease in three hospitals since 2014 Nov till 2016 July. Male to female were 43/59. The mean age was 33.1 years ( from 0.5 to 92.3 years). Two cases died of pulmonary hypertension and old age at 31 years old and 87 years old. Alfa-globin gene genotype studies were done in 44 cases. The (- -(SEA)) type of α(0)-thalassemia mutation was detected in all patients. Twenty- four (57.1%) cases were deletional (α(3.7)/ α(4.2)/unknown 19/4/1) and 20 (42.9%) were nondeletional (CS/RS 18/2) type. The mean of Hemoglobin (Hb) and serum ferritin level were 8.7 g/dL and 730 ng/mL. We also revealed the positive correlation between age and serum ferritin level. The liver iron concentration (LIC) were 6.694 mg Fe/g dw (n=35). The Hb, ferritin and LIC level were not different between deletional and non- deletional groups. They received the transfusion management : 1 with regular transfusion ≦ 6 weeks interval, 5 with irregular transfusion ≧ 6 weeks interval, 27 with occasional transfusion and 57 without transfusion. Fifteen cases received splenectomy. There were significantly higher prevalence for transfusion frequency and splenectomy in non-deletional group. The prevalence of morbidities were 16/79 for cholelithiasis, 12/90 for thromboembolic event, 4/90 for heart failure symptoms ( 2 for pulmonary hypertension), 5/90 for arrhythmia, 3/90 for bone fracture, 5/20 for osteoporosis and 0 for renal stone. There were non-significantly higher prevalence for morbidities in non-deletional group.

Discussion & Conclusion The study provides the clinical features and the prevalence of morbidities in Hb H disease in Taiwan. Surprisingly, the prevalence of thromboembolic event and pulmonary hypertension are overlooked in our routine Hb H disease care. We need to schedule close and careful clinical follow up of Hb H patients as they get older, they get some morbidities or they are non-deletional genotype.