A Prospective Analysis for Prevalence of Complications in Thai Nontransfusion-dependent Hb E/β-thalassemia and α-thalassemia (Hb H Disease)

Recently, complications in patients with nontransfusion-dependent thalassemia (NTDT), in particular those with β-thalassemia intermedia (β-TI), were found to be significantly different from those in patients with transfusion dependent thalassemia (TDT), mainly β-thalassemia major (β-TM). However, this information is rather limited in other forms of NTDT. In this prospective study, adult Thai NTDT patients were interviewed and clinically evaluated for thalassemia related complications. Fifty-seven NTDT patients (age 18-74 years), 59.6% Hb E/β-thalassemia and 40.4% Hb H disease, were recruited; 26.4% were splenectomized. The most common complications were gallstones (68.4%), osteoporosis (26.3%), and pulmonary hypertension (15.8%). Splenectomy was associated with higher rate of gallstones and serious infection (P = .001 and .052, respectively), consistent with a multivariate analysis (RR = 9.5, P = .044, and RR = 15.1, P = .043, respectively). In addition, a higher hemoglobin level was inversely associated with gallstones in both univariate and multivariate analyses (P = .01 and .022, respectively). Serum ferritin was associated with abnormal liver function (P = .002). In contrast to the previous study, the prevalence of thrombosis was less common in our population (1.7%), probably due to differences in transfusion therapy, ethnicity, and underlying genotypes. For the first time, this prospective study provided the current prevalence of NTDT related complications in a Southeast Asian population with a different underlying genetic basis compared with previous studies. Although individual prevalence of each complication might differ from other studies, several important clinical factors such as splenectomy, degree of anemia, and iron overload seem to be determining risks of developing these complications consistently across different ethnicities.