Primary HBB gene mutation severity and long-term outcomes in a global cohort of ß-thalassaemia.

In ß-thalassaemia, the severity of inherited ß-globin gene mutations determines the severity of the clinical phenotype at presentation and subsequent transfusion requirements. However, data on associated long-term outcomes remain limited. We analysed data from 2109 ß-thalassaemia patients with available genotypes in a global database. Genotype severity was grouped as ß0 /ß0 , ß0 /ß+ , ß+ /ß+ , ß0 /ß++ , ß+ /ß++ , and ß++ /ß++ . Patients were followed from birth until death or loss to follow-up. The median follow-up time was 34·1 years. Mortality and multiple morbidity outcomes were analyzed through five different stratification models of genotype severity groups. Interestingly, ß0 and ß+ mutations showed similar risk profiles. Upon adjustment for demographics and receipt of conventional therapy, patients with ß0 /ß0 , ß0 /ß+ , or ß+ /ß+ had a 2·104-increased risk of death [95% confidence interval (CI): 1·176-3·763, P = 0·011] and 2·956-increased odds of multiple morbidity (95% CI: 2·310-3·784, P < 0·001) compared to patients in lower genotype severity groups. Cumulative survival estimates by age 65 years were 36·8% for this subgroup compared with 90·2% for patients in lower genotype severity groups (P < 0·001). Our study identified mortality and morbidity risk estimates across various genotype severity groups in patients with ß-thalassaemia and suggests inclusion of both ß+ and ß0 mutations in strata of greatest severity.

A complication risk score to evaluate clinical severity of thalassaemia syndromes.

The thalassaemia syndromes (TS) show different phenotype severity. Developing a reliable, practical and global tool to determine disease severity and tailor treatment would be of great value. Overall, 7910 patients were analysed with the aim of constructing a complication risk score (CoRS) to evaluate the probability of developing one or more complications. Nine independent variables were included in the investigation as predictors. Logistic regression models were used for Group A [transfusion-dependent thalassaemia (TDT)], Group B [transfused non-TDT (NTDT)] and Group C (non-transfused NTDT). Statistically significant predictors included age (years), haemoglobin levels, hepatic transaminases [alanine aminotransferase (ALT) and aspartate aminotransferase] and left-ventricular ejection fraction (LVEF) for Group A; age (years), age at first chelation (months), ALT and LVEF for Group B; and age (years), mean serum ferritin (SF) levels and LVEF for Group C. The area under the receiver operating characteristic curve was 84·5%, 82·1% and 80·0% for Groups A, Group B and Group C respectively, suggesting the models had good discrimination. Finally, the CoRS for each group was categorised into four risk classes (low, intermediate, high, and very high) using the centiles of its distribution. In conclusion, we have developed a CoRS for TS that can assist physicians in prospectively tailoring patients' treatment.