Inhibitor epidemiology in a cohort of South African people with haemophilia-A
Date
2016
Authors
Mafika, Ziphozonke
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Abstract
Background
There are currently no published data about inhibitor epidemiology in the South African haemophilia population. International published studies suggest that people of African descent may have a higher risk of developing inhibitors than other ethnic groups. The uncertainty about an associated risk to and inhibitor risk in the South African patient population motivated the research question in this study. The majority of patients with haemophilia in South Africa are black. We set out to examine the relationship between inhibitor development and the presence of risk factors in our patient population.
Materials and Methods:
We conducted asingle center retrospective study at the Haemophilia Comprehensive Care Center of the Charlotte Maxeke Johannesburg Academic Hospital, South Africa, between January 1989 and January 2010. The study was approved by the University of the Witwatersrand Human Research Ethics Committee. People with haemophilia (PWH) born in the study period were identified in the centre database. All previously untreated patients (PUPs) with severe haemophilia A born betweenJanuary 1st1989 and January 1st 2010 were included. Data on treatment upto and ≥ 50 exposure days(ED) or inhibitor development were collected. All data on every reason for treatment and the clotting factor (CFC) used were
collected. Demographic information, family history of inhibitors, exposure days, type of treatment given, inhibitor test results, inhibitor risk factors, genetic analyses were extracted from the hospital patient records, clinical laboratory information system and genetic counselling files. Data was anonymized and coded prior to analysis.
Results:
Of the 117 files screened, 85 met the eligibility criteria. The race breakdown/ethnicity of the 85 was 67% black, 29% white and 3% mixed race. The mean number of EDs was 143for the entire group while the mean number of EDs was 114 for the inhibitor patients with a range of 30 to 498. Just over 17.6 %(15/85) developed inhibitors of which 80% were black, 13% white and 7% mixed race. From the 85 patients 15/85 developed an inhibitor of which 80% were low titre and 20% were high titre inhibitors. A positive family history of haemophilia was present in 60% of inhibitor patients. In the 37/85 patients with mutation results, 16 had Inversion 22 and 21 had other mutations. In this PUP cohort, none of the PWH with inversion 22 developed inhibitors. None of the cohort patients were on CFC prophylaxis, used recombinant CFCs or switched CFCs during the study period.
Conclusion
The inhibitor incidence of 17.6% in ourblack patient cohort is similar to other studies and does not support the suggestion that patients from black ancestry have a higher inhibitor incidence when compared to other ethnic groups.
Description
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Haematology,
Johannesburg, 2016