Coagulation factor V (FV) inhibitor is a rare disease with a mortality rate of nearly 15%. Increased mortality was significantly associated with the incidence of major bleeding, according to a review of PubMed case reports published in Thrombosis Update.
FV autoantibodies are most often detected in patients in the postoperative state, in those who have received a blood transfusion, in patients treated with antibiotics, and in those with immune diseases, according to the online report by Hideo Wada, MD, PhD, of the Mie Prefectural General Medical Center, Yokkaichi, Japan, and colleagues. These patients who acquired immune FV inhibitor (AIFVD) vary widely in symptoms from asymptomatic to mild or severe hemorrhagic manifestations, with some reports of thrombotic complications, the authors added.
Their review assessed the PubMed literature from Jan. 1, 1968, to July 31, 2020, and found 212 case reports on acquired FV deficiency. Of these, 150 cases with confirmed FV inhibitor positivity were included. The 150 reported cases of FV inhibitor were primarily from the United States (n = 48) and Japan (n = 43). The median patient age was 68.0 years, and the female to male ratio of patients was 0.47, according to the authors. The largest associated percentage of underlying conditions were postoperative state (25.3%), idiopathic (18.7%), infection (12.7%) and malignant neoplasms and autoimmune disease, at 7.3% each.
Major bleeds
A total of 73 cases were positive for major bleeding (48.7%) and 30 cases were negative (20.0%), while the rest were undetermined (31.3%). The FV activity was ≤ 28% in all patients with FV inhibitor.
The overall mortality rate was 14.6%, with half of the nonsurvivors dying of major bleeding. The mortality rate was more than twofold higher in the group with major bleeding (23.3% mortality) compared to the group without major bleeding (10.0%), yielding an odds ratio of 2.73 of death because of a major bleed. The most frequent types of fatal bleeding were intracranial bleeding and gastrointestinal bleeding. Of the 20 deaths reported in 135 patients with data, the causes of death were major bleeding (12 patients), infection (6 patients) and thrombosis (2 patients). Remission was observed in three of the nonsurvivors, indicating that even after remission, patients with FV inhibitor might still be susceptible to infection or thrombosis, according to the authors.
“[Major bleeding] should be treated aggressively; however, the best treatment is not clear and even patients in remission should be followed closely due to the risk of death from infection or thrombosis,” the authors concluded.
They reported having no conflicts of interest.