Inhibitor development and mortality in non-severe hemophilia A

Abstract

Background: The life expectancy of non-severe hemophilia A (HA) patients equals the life expectancy of the non-hemophilic population. However, data on the effect of inhibitor development on mortality and on hemophilia-related causes of death are scarce. The development of neutralizing factor VIII antibodies in non-severe HA patients may dramatically change their clinical outcome due to severe bleeding complications.

Objectives: We assessed the association between the occurrence of inhibitors and mortality in patients with non-severe HA.

Methods: In this retrospective cohort study, clinical data and vital status were collected for 2709 non-severe HA patients (107 with inhibitors) who were treated between 1980 and 2011 in 34 European and Australian centers. Mortality rates for patients with and without inhibitors were compared.

Results: During 64,200 patient-years of follow-up, 148 patients died (mortality rate, 2.30 per 1000 person-years; 95% confidence interval (CI), 1.96-2.70) at a median age of 64 years (interquartile range [IQR], 49-76). In 62 patients (42%) the cause of death was hemophilia related. Sixteen inhibitor patients died at a median age of 71 years (IQR, 60-81). In ten patients the inhibitor was present at time of death; seven of them died of severe bleeding complications. The all-cause mortality rate in inhibitor patients was > 5 times increased compared with that for those without inhibitors (age-adjusted mortality rate ratio, 5.6).

Conclusion: Inhibitor development in non-severe hemophilia is associated with increased mortality. High rates of hemophilia-related mortality in this study indicate that non-severe hemophilia is not mild at all and stress the importance of close follow-up for these patients.

Keywords: cause of death; hemophilia A; hemorrhage; mortality; neutralizing antibodies.