Ban, L, Abdul Sultan, A, West, J, Tata, LJ, Riley, RD, Nelson-Piercy, C and Grainge, MJ (2021) External validation of a model to predict women most at risk of postpartum venous thromboembolism: Maternity clot risk. Thrombosis Research, 208. pp. 202-210. ISSN 0049-3848

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INTRODUCTION: Venous thromboembolism (VTE) is the leading cause of direct maternal mortality in high-income countries. We previously developed a risk prediction score for postpartum venous thromboembolism (VTE) in women without a previous VTE. In this paper, we provide further external validation and assess its performance across various groups of postpartum women from England. MATERIALS AND METHODS: Cohort study using primary and secondary care data covering England. We used data from QResearch comprising women with pregnancies ending in live birth or stillbirth recoded in Hospital Episodes Statistics between 2004 and 2015. Outcome was VTE in the 6 weeks postpartum. Our predictor variables included sociodemographic and lifestyle characteristics, pre-existing comorbidities, and pregnancy and delivery characteristics. RESULTS: Among 535,583 women with 700,185 deliveries, 549 VTE events were recorded (absolute risk of 7.8 VTE events per 10,000 deliveries). When we compared predicted probabilities of VTE for each woman from the original model with actual VTE events, we obtained a C-statistic of 0.67 (95% CI 0.65 to 0.70). However, our model slightly over-predicted VTE risk for the higher risk women (calibration slope = 0.84; 95% CI 0.74 to 0.94). Performance was similar across groups defined by calendar time, socioeconomic status, age group and geographical area. The score performed comparably with the existing algorithm used by the UK Royal College of Obstetrician and Gynaecologists. CONCLUSIONS: Our model enables flexibility in setting new treatment thresholds. Adopting it in clinical practice may help optimise use of low-molecular-weight heparin postpartum to maximise health gain by better targeting of high-risk groups.

Item Type: Article
Additional Information: The final version of this accepted article and all relevant information related to it can be found online at;
Uncontrolled Keywords: Electronic health data; Venous thromboembolism; Childbirth; Risk prediction score; Thromboprophylaxis; Cohort study
Subjects: R Medicine > RC Internal medicine > RC666 Diseases of the circulatory (Cardiovascular) system
Divisions: Faculty of Medicine and Health Sciences > School of Primary, Community and Social Care
Related URLs:
Depositing User: Symplectic
Date Deposited: 21 Jul 2021 11:03
Last Modified: 08 Jun 2022 01:30

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