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Risks of post-colonoscopic polypectomy bleeding and thromboembolism with warfarin and direct oral anticoagulants: a population-based analysis
  1. Louis HS Lau1,2,
  2. Cosmos LT Guo1,
  3. Terry CF Yip2,3,
  4. Joyce WY Mak1,2,
  5. Sunny H Wong1,2,4,
  6. Kelvin LY Lam1,
  7. Grace LH Wong1,2,3,
  8. Siew C Ng1,2,4,
  9. Francis KL Chan1,2
  1. 1Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
  2. 2Institute of Digestive Diseases, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
  3. 3Medical Data Analytic Centre, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
  4. 4State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
  1. Correspondence to Professor Francis KL Chan, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong 999077, Hong Kong; fklchan{at}


Background There were limited data on the risk of post-polypectomy bleeding (PPB) in patients on direct oral anticoagulants (DOAC). We aimed to evaluate the PPB and thromboembolic risks among DOAC and warfarin users in a population-based cohort.

Methods We performed a territory-wide retrospective cohort study involving patients in Hong Kong from 2012 to 2020. Patients who received an oral anticoagulant and had undergone colonoscopy with polypectomy were identified. Propensity-score models with inverse probability of treatment weighting were developed for the warfarin-DOAC and between-DOAC comparisons. The primary outcome was clinically significant delayed PPB, defined as repeat colonoscopy requiring haemostasis within 30 days. The secondary outcomes were 30-day blood transfusion requirement and new thromboembolic event.

Results Apixaban was associated with lower PPB risk than warfarin (adjusted HR (aHR) 0.39, 95% CI 0.24 to 0.63, p<0.001). Dabigatran (aHR 2.23, 95% CI 1.04 to 4.77, adjusted p (ap)=0.035) and rivaroxaban (aHR 2.72, 95% CI 1.35 to 5.48, ap=0.002) were associated with higher PPB risk than apixaban. In subgroup analysis, apixaban was associated with lower PPB risk in patients aged ≥70 years and patients with right-sided colonic polyps.

For thromboembolic events, apixaban was associated with lower risk than warfarin (aHR 0.22, 95% CI 0.11 to 0.45, p<0.001). Dabigatran (aHR 2.60, 95% CI 1.06 to 6.41, ap=0.033) and rivaroxaban (aHR 2.96, 95% CI 1.19 to 7.37, ap =0.013) were associated with higher thromboembolic risk than apixaban.

Conclusions Apixaban was associated with a significantly lower risk of PPB and thromboembolism than warfarin, dabigatran and rivaroxaban, particularly in older patients with right-sided polyps.

  • colonoscopy
  • endoscopic polypectomy
  • gastrointestinal bleeding
  • cardiovascular complications
  • coagulation

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  • Contributors LHSL was responsible for conception and design of study, data retrieval and drafting of manuscript; CLTG and TCFY were involved in data retrieval and statistical analysis; JWYM, SHW, KLYL, GLHW and SCN provided critical comments and review of manuscript; FKLC was involved in conception and supervision of study.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study was approved by the Joint Chinese University of Hong Kong—New Territories East Cluster Clinical Research Ethics Committee (CREC Reference Number: 2017.335).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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