Brigitte Tardy-Poncet1, Emmanuel de Maistre2, Claire Pouplard3, Emilie Presles1, Martine Alhenc-Gelas4, Dominique Lasne5,6, Marie-Hélène Horellou7, Christine Mouton8, Anne Serre-Sapin9, Anne Bauters10, Philippe Nguyen11, François Mullier12, Julien Perrin13, Grégoire Le Gal14, Pierre-Emmanuel Morange15, Lélia Grunebaum16, Agnès Lillo-Le Louet17, Ismail Elalamy18, Yves Gruel3, Andreas Greinacher19, Thomas Lecompte20, Bernard Tardy1. 1. CIC 1408, Inserm U1059 SAINBIOSE, F-Crin INNOVTE, Université de Lyon, Saint-Etienne, France. 2. Hemostasis Unit, CHU Dijon, Dijon, France. 3. Division of Hematology - Hemostasis, University Hospital of Tours, Tours, France. 4. Hemostasis Unit, Hopital Européen Georges Pompidou, AP-HP, Paris, France. 5. Hemostasis Unit, Hôpital Necker, AP-HP, Paris, France. 6. Université Paris Sud Paris Saclay, Inserm U1176, Le Kremlin-Bicêtre, France. 7. Hematology Laboratory Unit, Hôpital Universitaire Paris-centre, Paris, France. 8. Hemostasis Unit, CHU Bordeaux, Bordeaux, France. 9. Hemostasis Unit, CHU Clermont-Ferrand, Clermont-Ferrand, France. 10. Hemostasis Unit, CHU Lille, Lille, France. 11. Hemostasis Unit, CHU Reims, Reims, France. 12. Namur Thrombosis and Hemostasis Center, Hematology Laboratory, Université catholique de Louvain, CHU UCL Namur, Yvoir, Belgium. 13. Hemostasis Unit, CHU Nancy, Nancy, France. 14. Department of Medicine, University of Ottawa, Ottawa Hospital Research Institute, Thrombosis Research Group, Ottawa, ON, Canada. 15. C2VN, Aix Marseille University, INSERM, INRA; Laboratory of Hematology, La Timone Hospital, Assistance Publique des Hôpitaux de Marseille, Marseille, France. 16. Laboratory of Hematology, CHU Strasbourg, Strasbourg, France. 17. Pharmacovigilance Center, Georges Pompidou European Hospital, AP-HP, Paris, France. 18. Hematology and Thrombosis Center, Tenon University Hospital, INSERM UMRS 938, Sorbonne University, Paris, France. 19. Institut fuer Immunologie und Transfusionsmedizin, Universitaetsmedizin Greifswald, Greifswald, Germany. 20. Department of Medicine, Geneva University Hospitals, and Geneva Platelet Group (GpG), Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Abstract
BACKGROUND: Diagnosis of heparin-induced thrombocytopenia (HIT) requires pretest probability assessment and dedicated laboratory assays. OBJECTIVE: To develop a pretest score for HIT. DESIGN: Observational; analysis of prospectively collected data of hospitalized patients suspected with HIT (ClinicalTrials.gov NCT00748839). SETTING: Thirty-one tertiary hospitals in France, Switzerland, and Belgium. PATIENTS: Patients tested for HIT antibodies (2280 evaluable), randomly allocated to derivation and validation cohorts. MEASUREMENTS: Independent adjudicators diagnosed HIT based on the prospectively collected data and serotonin release assay results. RESULTS: Heparin-induced thrombocytopenia was diagnosed in 234 (14.7%) and 99 (14.5%) patients in the two cohorts. Eight features were associated with HIT (in brackets, points assigned for score calculation of the score): unfractionated heparin (1); therapeutic-dose heparin (1); cardiopulmonary bypass (cardiac surgery) (2); major trauma (3); 5- to 21-day interval from anticoagulation initiation to suspicion of HIT (4); ≥40% decrease in platelet count over ≤6 days (3); thrombotic event, arterial (3) or venous (3). The C-statistic was 0.79 (95% CI, 0.76-0.82). In the validation cohort, the area under the receiver operating characteristic curve was 0.77 (95% CI, 0.74-0.80). Three groups of scores were defined; HIT prevalence reached almost 30% in the high-probability group. LIMITATION: The performance of the score may depend on settings and practices. CONCLUSION: The objective, easy-to-collect, clinical features of HIT we evidenced were incorporated into a pretest score, which may guide clinical decisions regarding diagnostic testing and anticoagulation.
BACKGROUND: Diagnosis of heparin-induced thrombocytopenia (HIT) requires pretest probability assessment and dedicated laboratory assays. OBJECTIVE: To develop a pretest score for HIT. DESIGN: Observational; analysis of prospectively collected data of hospitalized patients suspected with HIT (ClinicalTrials.gov NCT00748839). SETTING: Thirty-one tertiary hospitals in France, Switzerland, and Belgium. PATIENTS: Patients tested for HIT antibodies (2280 evaluable), randomly allocated to derivation and validation cohorts. MEASUREMENTS: Independent adjudicators diagnosed HIT based on the prospectively collected data and serotonin release assay results. RESULTS: Heparin-induced thrombocytopenia was diagnosed in 234 (14.7%) and 99 (14.5%) patients in the two cohorts. Eight features were associated with HIT (in brackets, points assigned for score calculation of the score): unfractionated heparin (1); therapeutic-dose heparin (1); cardiopulmonary bypass (cardiac surgery) (2); major trauma (3); 5- to 21-day interval from anticoagulation initiation to suspicion of HIT (4); ≥40% decrease in platelet count over ≤6 days (3); thrombotic event, arterial (3) or venous (3). The C-statistic was 0.79 (95% CI, 0.76-0.82). In the validation cohort, the area under the receiver operating characteristic curve was 0.77 (95% CI, 0.74-0.80). Three groups of scores were defined; HIT prevalence reached almost 30% in the high-probability group. LIMITATION: The performance of the score may depend on settings and practices. CONCLUSION: The objective, easy-to-collect, clinical features of HIT we evidenced were incorporated into a pretest score, which may guide clinical decisions regarding diagnostic testing and anticoagulation.