VPB0746 - Alterations in Coagulation Profiles and Bleeding Rates in Patients with Acute Myeloid Leukemia/Myelodysplastic Syndrome on Prophylactic Anti-Bacterials

Background: Patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) often receive anti-bacterial prophylaxis. Anti-bacterials are shown in other populations to interfere with vitamin K metabolism and induce elevations in international normalized ratio (INR). The impact these agents have on the coagulation profiles and bleeding risk in patients with AML/MDS, who are subject to additional acquired coagulopathy and disease-related challenges, is unknown.

Aims: To compare the coagulation profiles and bleeding rates of patients with AML/MDS on and off prophylactic anti-bacterials.

Methods: With institutional review board approval, we conducted a retrospective cohort study of adult patients with active AML/MDS and were admitted to Yale-New Haven Hospital between 2015-2019. The cohort was divided into patients on and off prophylactic anti-bacterials. Patients with acute/chronic liver disease, with disseminated intravascular coagulation, on anticoagulation or current/recent therapeutic anti-bacterials were excluded. Demographic/admission laboratory parameters and bleeding rates were extracted. Pearson’s χ2 tests and Wilcoxon rank tests were used for bivariate analyses.

Results: Among 759 unique patient hospital encounters, 28 occurred while on and 99 were off anti-bacterial prophylaxis (Table 1). Median duration of pre-admission anti-bacterial exposure was 3 (range: 0.06-24) months. Patients on anti-bacterial prophylaxis had higher INR (p=0.0001), and rates of partial thromboplastin time (PTT) prolongation (60.7% vs. 12.1%, p=0.0001); isolated INR elevation was also more common (46.4% vs. 9.1%, p< 0.0001). Patients off anti-bacterial prophylaxis had higher rates of bleeding (26.3% vs. 7.1%, p=0.031), including a numerically higher rate of major/clinically relevant bleeding (Table 2).

Conclusion(s): Patients with AML/MDS on anti-bacterial prophylaxis were more likely to have an abnormal coagulation profile when compared with their counterparts not on prophylaxis. However, rates of bleeding were higher in patients not on prophylaxis and this requires further study. These data demonstrate that recommended anti-bacterials do not appear to increase the bleeding risk in patients with AML/MDS.