Simple clotting tests may help speed diagnosis of acquired hemophilia A
Singapore study ties later diagnosis to longer stays and greater transfusion needs
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- Early recognition of acquired hemophilia A (AHA) is especially important in older patients with unexplained bruising or anemia.
- Ordering simple blood clotting tests at the first hospital contact may help prevent diagnostic delays.
- Later diagnosis was associated with longer hospital stays and greater red blood cell transfusion needs.
Recognizing acquired hemophilia A (AHA) early and ordering simple blood clotting tests in older patients with unexplained bruising or anemia — a low number of red blood cells — may help shorten diagnostic delays, according to a Singapore study in which the median time to diagnosis was four days, shorter than typically reported internationally.
Researchers said the shorter diagnostic interval may reflect access to blood specialists, called hematologists, and rapid coagulation-factor testing. The study, “Predictors and Clinical Impact of Time to Diagnosis in Acquired Haemophilia A: An 11-Year Retrospective Cohort Study,” was published as a letter to the editor in Haemophilia.
AHA often first appears outside hematology care
AHA occurs when the immune system mistakenly attacks factor VIII, a blood-clotting protein. Without sufficient factor VIII, the blood cannot clot properly, increasing the risk of excessive bleeding, as in other forms of hemophilia. Because AHA is uncommon, it is often first seen by doctors who are not blood specialists, which can delay diagnosis.
The researchers wanted to identify the factors that affect how quickly AHA is diagnosed and whether delays are associated with worse outcomes. They reviewed medical records of 90 patients treated at Singapore General Hospital and two affiliated hospitals over 11 years. More than half (53.3%) were age 75 or older, and the median age was 76.
Most patients (84.4%) were first admitted under general medicine rather than hematology, underscoring that most patients in this study initially presented outside hematology care. The median time to diagnosis, defined as the time between a patient’s first hospital contact and laboratory confirmation of AHA, was four days. The authors said this compared favorably with the seven to 30 days reported in international registries, although those studies measured diagnostic delay differently.
The strongest predictor of delayed diagnosis was failing to order simple blood clotting tests, which measure how well the blood clots, at the patient’s first hospital contact. About one in five patients did not receive these tests initially, which was associated with a nearly fivefold increase in time to diagnosis.
Patients with clear signs of bleeding were diagnosed more quickly. In contrast, those with subtler signs, including superficial bruising, unexplained anemia, or only a prolonged activated partial thromboplastin time — a test that measures part of the blood-clotting process — experienced longer delays.
Patients living in nursing homes and those with severe anemia at presentation also experienced longer delays. Among patients with severe anemia but no overt bleeding, the median time to diagnosis was 22 days, compared with four days for those who had severe anemia and overt bleeding.
Diagnostic delays tied to longer stays, greater transfusion needs
However, patients diagnosed four or more days after their first hospital contact stayed in the hospital longer and required more than twice as many units of transfused red blood cells as those diagnosed sooner, even after researchers accounted for factor VIII levels, inhibitor levels, and other clinical factors.
Most patients (70%) received immunosuppressive treatment with prednisolone, a corticosteroid, and cyclophosphamide. More than 80% achieved complete remission, meaning the disease became inactive, after a median of 72 days, or about 2.5 months. However, sepsis during immunosuppressive treatment was a major contributor to illness and death.
Overall, the study found that later diagnosis was associated with longer hospital stays and greater need for red blood cell transfusions. The findings suggest that educating non-specialist doctors to recognize AHA symptoms earlier and consider clotting tests in older patients with bruising or unexplained anemia may help reduce diagnostic delays and improve outcomes.
“Two targets emerge most clearly from our data: identifying groups of patients at risk of diagnostic delay, and improving recognition of AHA among the non-specialists who first encounter it through targeted clinician education,” the researchers concluded, noting that these represent “modifiable” targets.
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