Perioperative Outcomes Associated with Inhibitor Status in Patients with Hemophilia - a Retrospective Cohort Study
Authors: Olasupo Omotola O. , Nakar Charles , Iorio Alfonso , Haddix Craig , Mathew Thushara , Malec Lynn M , Matino Davide , Mbuagbaw Lawrence , Tarride Jean-Eric , Shapiro Amy D. 
Published: November 2021

Abstract
Background
The development of antibodies (inhibitors) to clotting factors compromises the treatment of people with Hemophilia A (HA) and B (HB), and results in ineffective clotting-factor therapy, higher risk of complications, and need for bypassing agents to achieve hemostatic control.
Objectives
To evaluate the association between presence of inhibitors and peri-operative hemostatic control, complications, and deviations from pre-surgery plans.
Methods
We conducted a retrospective study using data from the Indiana Hemophilia and Thrombosis Center (IHTC) surgical database (1998 - 2019). Association between specified outcomes and inhibitor status at surgery was assessed using generalized linear models while controlling for patient and procedural characteristics.
Results
A total of 1,492 surgeries were conducted in 539 patients with HA or HB, 4.8%(72/1492) of which were conducted in 20 (15 HA; 5HB) patients with inhibitors. Of the 72 surgeries involving inhibitors, 30 were high-titer, 10 low-titer and 32 with unreported inhibitor titers.
Adjusting for patient's age, hemophilia diagnosis, surgery setting, and surgery type, the risk of achieving perioperative hemostasis was lower in surgeries involving inhibitors compared to non-inhibitor surgeries (65.6% vs 91.4%; aRR=0.78; 95% CI= 0.61-0.99; p=0.038). Complications including hemorrhage, fever, pain, thrombosis, and infections occurred more frequently in surgeries involving inhibitors (31.7% vs 14.6%; aRR= 1.67, 95% CI= 1.07 - 2.63; p=0.025). Deviation from pre-surgical plans, usually due to the development of complications including lack of effective hemostatic control, also occurred more frequently in surgeries involving inhibitors compared to those without inhibitors (70.8 vs 39.5%; aRR= 1.63, 95% CI= 1.33 - 2.01; p&lt;0.001).
Conclusion
Procedures involving patients with inhibitors have increased risk of adverse perioperative outcomes compared to those without inhibitors.
Key Words: Inhibitors, Hemophilia, Surgery, Perioperative outcomes, Database.

Disclosures
Iorio: McMaster University: Current Employment; Bayer (funding to the institution): Research Funding; BioMarin (funding to the institution): Research Funding; NovoNordisk (funding to the institution): Research Funding; Octapharma (funding to the institution): Research Funding; Pfizer (funding to the institution): Research Funding; Roche (funding to the institution): Research Funding; Sanofi (funding to the institution): Research Funding; Sobi (funding to the institution): Research Funding; Takeda (funding to the institution): Research Funding. Malec: CSL Behring: Consultancy; Genentech: Consultancy; HEMA Biologics: Consultancy; Pfizer: Consultancy; Sanofi: Consultancy, Research Funding; Takeda: Consultancy. Matino: Bayer: Membership on an entity's Board of Directors or advisory committees, Other: research grants and personal fees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: research grants and personal fees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Other: research grants and personal fees; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: research grants and personal fees; Spark: Other: research grants; Octopharma: Membership on an entity's Board of Directors or advisory committees, Other: research grants and personal fees; Sobi: Membership on an entity's Board of Directors or advisory committees, Other: personal fees. Shapiro: Pfizer: Research Funding; Novartis: Research Funding; Sangamo: Other: Advisory board fees, Research Funding; Sigilon Therapeutics: Other: Advisory board fees, Research Funding; Bioverativ (a Sanofi company): Other: Advisory board fees, Research Funding; Daiichi Sankyo: Research Funding; Genentech: Other: Advisory board fees, Research Funding, Speakers Bureau; Glover Blood Therapeutics: Research Funding; Kedrion Biopharma: Research Funding; Novo Nordisk: Other: Advisory board fees, Research Funding, Speakers Bureau; Prometric BioTherapeutics: Research Funding; Octapharma: Research Funding; OPKO: Research Funding; Agios: Research Funding; BioMarin: Research Funding; Takeda: Research Funding.