PB0195 - Prevalence of Sporadic Haemophilia A: an updated analysis of two cohort studies

Background: Haemophilia A (HA) is an inherited bleeding disorder caused by mutations in the factor VIII (FVIII) coding gene (F8). In Brazil, family structure has undergone great changes in the last decades resulting in reduced childbirth rates with longer life expectancy. Therefore, we have hypothesised that the prevalence of familial HA might have changed over the years.

Aims: The aim of this study was to evaluate the proportion of sporadic and familial HA in two Brazilian studies.

Methods: The HEMFIL Study is a multicentric prospective cohort of previously untreated patients (PUPs) with HA which aims to identify risk factors for inhibitor development. The BrazIT Study is a multicentric cohort study of patients with HA on immune tolerance induction (ITI) which aims to identify predictors of response of ITI. We included patients with HA (PwHA) with FVIII < 2%. We assessed clinical, laboratory and F8 genotype by validated questionnaires and analysis of medical records. We also investigated the inheritance status by assessing the history of HA of each patient’s families. For statistical analysis of non-parametric variables, we used Fisher Exact Test. The participants signed informed consent and the study was approved by the ethics committee.

Results: A total of 264 PwHA were included. Median age was 15 years. The overall prevalence of sporadic HA was 44,3%, without difference between studies (46.5% HEMFIL vs 43.0% BrazIT; p=0,37). To verify whether the prevalence of sporadic HA cases has changed over time, we stratified PwHA into five age ranges (≤10; 10-19,9; 20-29,9; 30-39,9 and ≥ 40 years). The frequency of sporadic PwHA increased from 18,8% in patients ≥ 40 years to 49,7% in PwHA ≤ 10 years (p=0.006).

Conclusion(s): The prevalence of sporadic HA increased about 3 times within the last 40 years in Brazil. This likely reflects the changes in family structure in the country.