Incidence and Outcomes of Heparin-Induced Thrombocytopenia Associated with a Heparin Shortage at a Large Academic Medical Center

Heparin-induced thrombocytopenia (HIT) is a life-threatening complication associated with significant morbidity and mortality in hospitalized patients. The 2019 African swine fever outbreak in China resulted in a critical national shortage of porcine-derived heparin products in the United States. As a result, our institution implemented a multitude of mitigation strategies to reduce heparin utilization by >80% and optimize safe and effective alternative therapies. The aim of this study was to determine whether this change in clinical practice impacted the incidence of HIT and associated outcomes.

A single-center, retrospective cohort study was performed on patients admitted to Massachusetts General Hospital who were ≥ 18 years of age and had a positive platelet factor 4 (PF4) drawn between February 2019 and January 2020. Patient demographics, comorbidities, baseline labs, serotonin release assay results, timing and magnitude of platelet count fall, and characteristics of heparinoid and non-heparinoid anticoagulant use were collected from the medical record. Thrombotic and hemorrhagic outcomes were characterized.

Seventy-five patients were included in the final analysis, of which 56 (75%) were critically-ill. Baseline characteristics were similar between groups including median age 66.8 years, 49% male, 80% Caucasian. Forty-four (59%) patients underwent surgery, 23 (31%) required continuous renal replacement therapy, and 13 (17%) underwent extracorporeal membrane oxygenation. Incidence of HIT with any exposure to heparinoid product was 0.3% and 0.15% (p=0.002) in the pre-shortage and shortage periods, respectively. In those who received therapeutic dose unfractionated heparin, incidence of HIT was 1.26% and 1.05% (p=0.63) in the pre-shortage and shortage groups, respectively. Thrombotic complications were observed in 19 (41%) patients in the pre-shortage group and 11 (38%) in the post-shortage group (p=0.77). Bleeding events were observed in 8 (17%) and 5 (17%) (p=0.99).

We observed a lower incidence of HIT resulting from our institution's efforts to conserve unfractionated heparin supply and utilize alternative anticoagulants during a critical national drug shortage. There were no significant differences in associated thrombotic and bleeding events.

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