The Prevalence of and Risk Factors Associated With Development of Factor Viii Inhibitors in Patients With Hemophilia a Seen at the Kenyatta National Hospital

Abstract

Background Hemophilia A is a global challenge affecting 1 in 5000 males. Up to 5% of the hemophiliacs on treatment develop inhibitors which neutralize infused factor concentrates reducing the effectiveness of treatment and predisposing the patient to life threatening complications. Kenyatta National Hospital (KNH) is a major treatment centre nationally attending to two thirds of the hemophilia patients registered in Kenya. Currently, routine screening of factor inhibitors is not practiced in Kenya hence the prevalence and associated risk factors are unknown. The aim of this study was to determine the prevalence of and risk factors associated with the development of Factor VIII inhibitors in patients with Hemophilia A at KNH. This will enable early detection and comprehensive management to avert life threatening bleeds, physical disability and reduce morbidity and mortality. Study Objective To determine the prevalence of and selected risk factors associated with the development of Factor VIII inhibitors in patients with Hemophilia A seen at Kenyatta National Hospital. Methodology This study was cross sectional, done at Kenyatta National Hospital using consecutive sampling. Clinical and socio-demographic data was collected using a questionnaire and blood samples were drawn for inhibitor testing. The study was carried out from January 2021 to January 2022. Data was entered in a secure database prior to exporting to Statistical Package for social Science version 21 for analysis. Prevalence of inhibitors in Hemophilia A patients was reported in proportions and univariate and multivariate analysis was used to analyze the selected risk factors associated with development of FVIII inhibitors in patients with Hemophilia A in KNH. Results The prevalence of FVIII inhibitors in the 61 patients tested with Hemophilia A seen at KNH was found to be 19.7% (n=12). All these patients had low titer inhibitors and severe hemophilia. Half of those with inhibitors were between 10 and 19 years. The risk factors associated with the development of inhibitors found that when age at first treatment was less than one year, one was five times more likely to develop inhibitors compared to those who received treatment for the first time when above fifteen years. Of those who had inhibitors 33.3% had received an average dose of 1000IU of factor. Fifty percent of those who had minor surgery developed inhibitors and had odds of 0.7 times less likely to develop inhibitors. Regarding medical history, 91.7% of those who had trauma and major bleeds were 3.6 times more likely to develop inhibitors. These findings were however not statistically significant. Conclusions The prevalence of Hemophilia A inhibitors in KNH patients is high 19.7% (n=12). Several risk factors were found to be associated with the development of inhibitors in this study are exposure to trauma, major bleeds and age at first treatment less than 1 year. Recommendations Routine testing of inhibitors to be standard of care in Hemophilia management across Kenya. Create more awareness on the existence of inhibitors in Hemophilia to avoid possible triggers by use of unnecessary blood products or unplanned surgeries. There needs to be a multidisciplinary approach in management of hemophiliacs to avoid risk of inhibitor development. Carry out health economic assessments on QALYs and DALYs to determine the actual socioeconomic burden of those with inhibitors to influence policy on affordable care like essential drugs for management of inhibitors in hemophilia A.