Effect of genotype on pulmonary hypertension risk in patients with thalassemia

Pulmonary hypertension is one of the major complications in patients with non-transfusion-dependent thalassemia (NTDT). Patients with NTDT have distinct genetic subgroups. Therefore, the effects of different genotype groups on pulmonary hypertension risk in patients with NTDT were assessed.

A cross-sectional study was conducted in patients with NTDT aged ≥ 10 yr old at Srinagarind University Hospital and Udonthani Hospital, Thailand. Pulmonary hypertension risk was defined as peak tricuspid regurgitation velocity > 2.9 m/s by trans-thoracic echocardiography. Clinical characteristics and laboratory data that literature has indicated as risk factors for pulmonary hypertension were collected. The effect of genotype group on pulmonary hypertension risk was evaluated by using multivariate logistic regression analysis.

Of 219 patients, pulmonary hypertension risk was found in 24 patients (10.96%). All patients were categorized into two groups according to genetic data that included: (i) β-thalassemia (139, 63.5%), (ii) α-thalassemia and combined α and β-thalassemia (80, 36.5%). Genotype groups were statistically and significantly associated with pulmonary hypertension risk based on the adjusted odds ratios after adjustment for other factors. Patients with β-thalassemia had a statistically significant higher risk for pulmonary hypertension risk (odds ratio = 9.47, P = 0.036) compared to patients with α-thalassemia and patients with combined α and β-thalassemia.

The genotype group is an independent risk factor for pulmonary hypertension in patients with NTDT. Echocardiography should be routinely recommended for all patients with β-thalassemia. Routine screening in patients with α-thalassemia and combined α and β-thalassemia, however, may not be necessary or should focus on the older population.