Download PDF
Thromb Haemost 2026; 126(01): 078-086
DOI: 10.1055/a-2544-6183
Stroke, Systemic or Venous Thromboembolism

Impact of Obesity and Overweight on Heparin Dosing and Clinical Outcomes in Pediatric Patients with Venous Thromboembolism

Authors

  • Alexandra Larouche

    1   Department of Pediatrics, CHU de Québec, Québec, QC, Canada

  • Valérie Dollo

    1   Department of Pediatrics, CHU de Québec, Québec, QC, Canada

  • Gabriel Mercier

    1   Department of Pediatrics, CHU de Québec, Québec, QC, Canada

  • Narcisse Singbo

    2   Recherche Clinique et Évaluative, Centre de Recherche du CHU de Québec, Québec, QC, Canada

  • Chantal Éthier

    3   Axe Reproduction, Santé de la Mère et de l'Enfant, Centre de Recherche du CHU de Québec, Québec, QC, Canada

  • Marie-Christine Boulanger

    4   Department of Pharmacy, CHU de Québec, Québec, QC, Canada

  • Marie-Claude Pelland-Marcotte 

    1   Department of Pediatrics, CHU de Québec, Québec, QC, Canada
    3   Axe Reproduction, Santé de la Mère et de l'Enfant, Centre de Recherche du CHU de Québec, Québec, QC, Canada

Funding This research was supported by a summer studentship from the Canadian Pediatric Thrombosis and Hemostasis Network. M.C.P.M. is supported by Fonds de Recherche en Santé du Québec Junior 1 Scholars Award.
Further Information
   Permissions and Reprints


Graphical Abstract

Abstract

Background

Dosing guidance for anticoagulation, the mainstay of venous thromboembolism (VTE) treatment, is lacking for obese children. We aimed to compare unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH) dosing requirements and clinical outcomes between obese/overweight and nonobese children.

Methods

This monocentric retrospective cohort study included patients aged < 18 years old receiving anticoagulation for VTE. The outcomes were: (1) number of dose adjustments to reach therapeutic levels, (2) variation from initial dose, (3) thrombotic progression/recurrence, and (4) clinically relevant bleeding. Characteristics and dosing requirements of obese/overweight and nonobese children were compared using Pearson chi-square, Fisher exact, and Wilcoxon Mann–Whitney tests. Kaplan–Meier estimator compared the cumulative incidence of thrombotic recurrence/progression and clinically relevant bleeding between groups.

Results

We included 212 patients (median age: 6.2 years, 23.6% obese/overweight) having 258 anticoagulation encounters (LMWH: 82.6%, UFH: 17.4%). Most children had therapeutic levels following one dosage (66.7% in obese/overweight vs. 51.8% in nonobese, p = 0.201). Dosing requirements significantly differed between obese/overweight and nonobese children (average increase from initial dose: 3.2 vs. 11.3%, p < 0.001). In obese/overweight children, 11.1% of patients required ≥ 10% dose reduction versus 2.1% in nonobese children (p < 0.001). The cumulative incidence of thrombotic progression/recurrence was comparable between groups (obese/overweight: 12.0%, nonobese: 10.5%, p = 0.786). Similarly, clinically significant bleeding was rare for both groups (obese/overweight: 2.0%, nonobese: 3.1%, p = 0.609).

Conclusion

In children treated for VTE, obesity/overweight was associated with lower anticoagulation requirements. Further prospective work is urgently needed to explore alternate regimens, such as dose capping, reduced initial dosing, or the use of fat-free mass.

Keywords

thrombosis - obesity - children - heparin

Authors' Contribution

M.C.P.M., A.L., and M.C.B. designed the study. A.L., V.D., and G.M. collected the data. M.C.P.M., M.N.U.S., and C.E. analyzed the data, and all authors contributed to interpretation of data. M.C.P.M. and C.E. prepared the first version of this manuscript, and all authors provided critical review of drafts and approved the final submitted version.


Supplementary Material



Publication History

Received: 27 November 2024

Accepted: 21 February 2025

Article published online:
24 March 2025

© 2025. Thieme. All rights reserved.

Georg Thieme Verlag KG
Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany