Performance of a clinical risk prediction model for inhibitor formation in severe haemophilia A.

BACKGROUND: There is a need to identify patients with haemophilia who have a very low or high risk of developing inhibitors. These patients could be candidates for personalized treatment strategies. AIMS: The aim of this study was to externally validate a previously published prediction model for inhibitor development and to develop a new prediction model that incorporates novel predictors. METHODS: The population consisted of 251 previously untreated or minimally treated patients with severe haemophilia A enrolled in the SIPPET study. The outcome was inhibitor formation. Model discrimination was measured using the C-statistic, and model calibration was assessed with a calibration plot. The new model was internally validated using bootstrap resampling. RESULTS: Firstly, the previously published prediction model was validated. It consisted of three variables: family history of inhibitor development, F8 gene mutation and intensity of first treatment with factor VIII (FVIII). The C-statistic was 0.53 (95% CI: 0.46-0.60), and calibration was limited. Furthermore, a new prediction model was developed that consisted of four predictors: F8 gene mutation, intensity of first treatment with FVIII, the presence of factor VIII non-neutralizing antibodies before treatment initiation and lastly FVIII product type (recombinant vs. plasma-derived). The C-statistic was 0.66 (95 CI: 0.57-0.75), and calibration was moderate. Using a model cut-off point of 10%, positive- and negative predictive values were 0.22 and 0.95, respectively. CONCLUSION: Performance of all prediction models was limited. However, the new model with all predictors may be useful for identifying a small number of patients with a low risk of inhibitor formation.

Mortality of patients with haemophilia in Brazil: First report.

INTRODUCTION: Brazil has the fourth largest world population of patients with haemophilia. However, mortality rates in this population are unknown. AIM: To analyse mortality and its causes in Brazilian patients with haemophilia from 2000 to 2014. METHODS: The number of deceased patients with haemophilia and causes of death were obtained from the Brazilian National Mortality Information System (SIM), according to the 10th International Classification of Diseases (ICD-10). Standardized mortality ratios (SMR) were calculated to estimate the rate of overall death of patients with haemophilia relative to that of the Brazilian general male population. RESULTS: A total of 784 deaths were identified in the period of 15 years. Mortality of patients with haemophilia was 13% higher when compared with the general male population (SMR 1.13, 95% CI: 1.01-1.16). Haemorrhage was the main cause of death (n = 254; 32.4%) of which 137 (54%) was intracranial haemorrhage. The total number of deaths due to HIV decreased over the years, and an increase in deaths due to cancer and cardiovascular disease was observed. A total of 129 deaths (16.5%) were related to hepatitis infection, of whom, 109 (86.5%) patients also presented with cirrhosis and hepatocellular carcinoma or other liver diseases. CONCLUSION: Mortality rate of Brazilian patients with haemophilia decreased over the evaluated period. Intracranial haemorrhage is still an important cause of death in these patients, which requires major effort for prevention. Death due to age-related cardiovascular disease and cancer has increased over the years, following the same tendency observed in developed countries.