title: Benefits of chronic blood transfusion in hemoglobin E/β thalassemia with pulmonary arterial hypertension.
abstract: OBJECTIVE
  The aim of the research reported here was to compare pulmonary artery systolic pressure (PASP) and 6-minute walk distance after 1 year of follow-up in hemoglobin E/β thalassemia (E/β-Thal) with pulmonary arterial hypertension (PAH) patients who received chronic blood transfusions versus those who received occasional transfusions.
  
  
  METHODS
  A nonrandomized clinical trial was conducted at the Hematological Outpatient Clinic of Chiang Rai Hospital, Thailand. All adult cases of E/β-Thal with PAH (defined as PASP >35 mmHg by Doppler echocardiography) were evaluated and followed for the next 12 months. The patients were classified into two groups by patient preference. Group 1 patients received chronic blood transfusions - one to two units of leukocyte-poor packed red cells every 2-4 weeks - over 1 year to maintain pre-transfusion hemoglobin levels of ≥7.0 g/dL. Group 2 patients received occasional transfusions over the course of 1 year, with more than 4 weeks between transfusions. All patients were treated with iron chelation when serum ferritin levels were ≥1,000 μg/dL. PASP and the 6-minute walk distance were evaluated at baseline and at 6 and 12 months. Propensity score adjustment was used to control for confounding by indication and contraindication. Multivariable regression analysis was used to evaluate the effects of chronic blood transfusion.
  
  
  RESULTS
  There were 16 (53.3%) patients in Group 1 and 14 (46.7%) in Group 2. At 12 months, patients in Group 1 had a greater reduction in PASP than those in Group 1 (adjusted mean difference, -16.83; 95% confidence interval, -26.35 to -7.32; P=0.001). The 6-minute walk distance at 12 months in Group 1 patients was greater than that in Group 2 patients (adjusted mean difference, 46.55; 95% confidence interval, 18.08 to 75.02; P=0.001).
  
  
  CONCLUSIONS
  This study found evidence that chronic blood transfusions may have beneficial effects in PAH in thalassemia patients over 1 year.
authors.affiliation: Clinical Epidemiology Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand ; Department of Medicine, Chiang Rai Hospital, Chiang Rai, Thailand.
authors.forename: Nonlawan
authors.initials: N
authors.lastname: Chueamuangphan
authors.affiliation: Clinical Epidemiology Program, Faculty of Medicine, Thammasat University, Bangkok, Thailand.
authors.forename: Jayanton
authors.initials: J
authors.lastname: Patumanond
authors.affiliation: Department of Medicine, Chiang Rai Hospital, Chiang Rai, Thailand.
authors.forename: Wattana
authors.initials: W
authors.lastname: Wongtheptien
authors.affiliation: Department of Medicine Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Weerasak
authors.initials: W
authors.lastname: Nawarawong
authors.affiliation: Department of Medicine Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Apichard
authors.initials: A
authors.lastname: Sukonthasarn
authors.affiliation: Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Suporn
authors.initials: S
authors.lastname: Chuncharunee
authors.affiliation: Clinical Epidemiology Society at Chiang Mai, Chiang Mai, Thailand.
authors.forename: Chamaiporn
authors.initials: C
authors.lastname: Tawichasri
keywords: 6-minute walk distance; Thailand; leukocyte-poor packed red cells; pulmonary artery systolic pressure