The Prevalence of clotting factor inhibitors in patients with hemophilia

Abstract

Background: Hemophilia A and B are X-linked diseases that predominantly affect male patients. Patients can develop coagulation factor inhibitors, which exponentially increases the treatment cost. Objective: This study aimed to determine the prevalence of factor VIII inhibitors. Materials and methods: This was an observational descriptive study. Clotting factor inhibitor screening was performed by activated partial thromboplastin time mixing studies using normal pooled plasma. Bethesda assay for quantitation of factor VIII inhibitors was performed on samples which were positive with screening tests.Results: Study was performed in total of 62 patients with Hemophillia. Out of 62 patients, Hemophilia A and Hemophilia B was observed in 92% cases and 7% cases respectively and 1 case was with Hemophillia and von willebrand disease(1%). Out of 62 patients, 39(63%) had severe hemophilia A, 18(29%) had moderate hemophilia A, and 5(8%) had mild hemophilia A. Mixing based inhibitor screening was positive in total 14 number of patients. Bethesda assay confirmed 10(16%) cases with presence of inhibitor. 4(40%) out of 10 patients were low responders (<5 BU), with mean BU of 2.88, and 6(60%) patients were high responders (>5 BU), with mean BU of 39.2. Diagnostics of mixing based inhibitor screening showed sensitivity and specificity of 75% & 60% at difference of ≥5 seconds and 60% & 100% for difference of ≥10 seconds.Conclusion: Mixing tests are an important first step in the investigation of inhibitors in cases with hemophilia as the follow up investigations are more costly and time consuming than the basic screening tests.