Treatment Patterns and Bleeding Risk of Anticoagulants in Patients With Venous Thromboembolism in Korea

Treatment Patterns and Clinical Outcomes Among Venous Thromboembolism Patients Treated With Anticoagulants After the Entry of Non-vitamin K Antagonist Oral Anticoagulants in Korea

This study is a retrospective, observational, nationwide population-based cohort study utilizing the South Korea's Health Insurance and Review Assessment Service (HIRA) database. The aims of this study are to describe the sociodemographic and clinical characteristics of patients with venous thromboembolism according to their anticoagulant treatment (parenteral anticoagulants, warfarin, or non-vitamin K antagonist oral anticoagulants), to describe the treatment patterns related to anticoagulants, and to examine the risk of major bleeding according to the specific type of oral anticoagulants. The study will be conducted in two phases: Phase I for descriptive study and Phase II for comparative study.

Study Overview

• Status: Completed
• Conditions: Venous Thromboembolism
• Intervention / Treatment: Drug: Parenteral anticoagulant; Drug: Warfarin; Drug: Apixaban; Drug: Rivaroxaban; Drug: Dabigatran; Drug: Edoxaban

• Study Type: Observational
• Enrollment (Actual): 55759

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seongnam-si, Korea, Republic of
    • Seoul National University Bundang Hospital
  • Suwon-si, Korea, Republic of
    • Sungkyunkwan University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Patients diagnosed with venous thromboembolism from the South Korea's Health Insurance Review and Assessment Service (HIRA) database between Mar 1, 2013 and Jun 30, 2019

Description

Inclusion Criteria:

1. Incident VTE diagnosis in an inpatient or outpatient setting between 1 Mar 2013 and 30 Jun 2019
2. Received anticoagulation therapy (all medication codes for anticoagulants approved for VTE in Korea; UFH, LMWH, warfarin, and NOACs) within 30 days of their VTE diagnosis (the index date will be defined as the date of treatment initiation with anticoagulants)
3. Aged ≥18 years at index date

Exclusion Criteria:

1. Had a record of VTE diagnosis within the 12-month period prior to the index VTE encounter.
2. Diagnosed with atrial fibrillation/flutter, mechanical heart valve replacement or mitral stenosis anytime prior to index date
3. Had a record of Inferior Vena Cava filter anytime prior to index date
4. Received anticoagulatory therapy within the 12-month period prior to index VTE encounter
5. Prescribed two different anticoagulants on the same index date
6. Had a record of pregnancy within the 9-month period prior to index date
7. Had a record of active cancer within the past 6 months of period prior to index date

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Parenteral anticoagulant only; LMWH, UFH	Drug: Parenteral anticoagulant; Parenteral anticoagulant only
Warfarin-based; Warfarin only + parenteral anticoagulant bridged warfarin	Drug: Warfarin; Warfarin-based
NOAC-based; NOAC only + parenteral anticoagulant bridged NOAC NOAC: apixaban, rivaroxaban, dabigatran, edoxaban	Drug: Apixaban; Apixaban; Drug: Rivaroxaban; Rivaroxaban; Drug: Dabigatran; Dabigatran; Drug: Edoxaban; Edoxaban

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Interruption in Index Anticoagulant Treatment	Treatment interruption was defined as when a participant had a gap with no new treatment within 30 days of the estimated end of supply of index treatment, but subsequently restarted the index treatment after this period of 30 days. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment interruption, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Time to Treatment Interruption	Treatment interruption was defined as when a participant had a gap with no new treatment within 30 days of the estimated end of supply of index treatment, but subsequently restarted the index treatment after this period of 30 days. The time to treatment interruption was defined as the period from the index date to the date of treatment interruption. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment interruption, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants Who Switched to Another Anticoagulant Therapy	Treatment switching was defined as a prescription of another anticoagulant therapy that was started after the treatment initiation of the index anticoagulant treatment and within 30 days after the estimated end of supply of the index anticoagulant drug (exposure to the new anticoagulant treatment must last for at least 30 days to be considered as a treatment switch). The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment switch, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Time to Treatment Switch	Treatment switching was defined as a prescription of another anticoagulant therapy that was started after the treatment initiation of the index anticoagulant treatment and within 30 days after the estimated end of supply of the index anticoagulant drug (exposure to the new anticoagulant treatment must last for at least 30 days to be considered as a treatment switch). The time to treatment switch was defined as the period from the index date to the date of treatment switch. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment switch, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants Who Completely Discontinued Index Anticoagulant Treatment	Treatment discontinuation (complete discontinuation; no reinitiation) was defined as when a participant who ended their first continuous treatment episode with the index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment discontinuation, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Time to Treatment Discontinuation	Treatment discontinuation (complete discontinuation; no reinitiation) was defined as when a participant who ended their first continuous treatment episode with the index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time. The time to treatment discontinuation was defined as the period from the index date to the date of treatment discontinuation. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to treatment discontinuation, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Overall Index Anticoagulant Treatment Duration	Overall anticoagulant treatment duration was defined as the time period from the index date to the earliest of treatment interruption, switch, or discontinuation. Treatment interruption: when a participant had a gap with no new treatment within 30 days of estimated end of supply of index treatment, but subsequently restarted index treatment after this period of 30 days. Treatment switching: a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Treatment discontinuation: when a participant who ended their first continuous treatment episode with index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time. The index date was defined as the date of first prescription for anticoagulants within 30 days after the index VTE event.	From index date up to the earliest of treatment interruption, switch, or discontinuation; during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants Who Were Persistent on Index Anticoagulant Treatment for 3 Months	Participants were considered to be persistent on index anticoagulant treatment if a participant had evidence of a repeat prescription within 30 days of the end of their prescription and does not experience any of the events that included treatment interruption (participant had a gap with no new treatment within 30 days of estimated end of supply of index treatment, but subsequently restarted index treatment after 30 days), switch (prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug), or discontinuation (participant ended their first continuous treatment episode with index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time). Index date: date of first prescription for anticoagulants within 30 days after the index VTE event.	Within 3 months of index date, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants Who Were Persistent on Index Anticoagulant Treatment for 6 Months	Participants were considered to be persistent on index anticoagulant treatment if a participant had evidence of a repeat prescription within 30 days of the end of their prescription and does not experience any of the events that included treatment interruption (participant had a gap with no new treatment within 30 days of estimated end of supply of index treatment, but subsequently restarted index treatment after 30 days), switch (prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug), or discontinuation (participant ended their first continuous treatment episode with index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time). Index date: date of first prescription for anticoagulants within 30 days after the index VTE event.	Within 6 months of index date, during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Index Anticoagulant Treatment Interruption	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment interruption. Treatment interruption was defined as when a participant had a gap with no new treatment within 30 days of the estimated end of supply of index treatment, but subsequently restarted the index treatment after this period of 30 days. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event.	Within 30 days before treatment interruption during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Major Bleeding	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "major bleeding" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Complications of VTE	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "complications of VTE" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Thromboembolism	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "thromboembolism" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Major Surgery	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "major surgery" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Cancer-related Event	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "cancer-related event" are reported among participants without active cancer. Data not collected and reported for participants with active because all participants already had cancer.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Kidney Function Change	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "kidney function change" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Switch From Index Anticoagulant Treatment: Liver Function Change	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment switch. Treatment switching was defined as a prescription of another anticoagulant therapy that was started after treatment initiation of index anticoagulant treatment and within 30 days after estimated end of supply of index anticoagulant drug. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event. In this outcome measure, results for event "liver function change" are reported.	Within 30 days before treatment switch during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)
Number of Participants With Clinical Events Preceding Index Anticoagulant Treatment Discontinuation	Clinical event preceding first treatment change was defined as occurrence of any event (major bleeding, complications of VTE, thromboembolism, major surgeries, cancer-related event, kidney function change, liver function change) within 30 days before treatment discontinuation. Treatment discontinuation (complete discontinuation; no reinitiation) was defined as when a participant who ended their first continuous treatment episode with the index anticoagulant treatment without switching, and subsequently have no further prescriptions for that respective anticoagulant treatment during all available follow-up time. Index date was defined as date of first prescription for anticoagulants within 30 days after index VTE event.	Within 30 days before treatment discontinuation during observation period of maximum up to 88 months (retrospective data was retrieved and observed during 1 month of this study)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical events preceding first treatment change	Clinical event preceding first treatment change will be defined as occurrence of any event - major bleeding, complication of VTE, thromboembolism, major surgery, new diagnosis of cancer, kidney function change, or liver function change - within 30 days before treatment interruption, switch, or discontinuation.	From index date to follow-up period (up to maximum duration of 81 months)

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): August 31, 2021
• Primary Completion (Actual): September 30, 2021
• Study Completion (Actual): September 30, 2021

Study Registration Dates

• First Submitted: August 20, 2021
• First Submitted That Met QC Criteria: August 20, 2021
• First Posted (Actual): August 26, 2021

Study Record Updates

• Last Update Posted (Actual): August 3, 2023
• Last Update Submitted That Met QC Criteria: September 15, 2022
• Last Verified: September 1, 2022

More Information

Terms related to this study

• Keywords: anticoagulant; Venous thromboembolism; treatment pattern; bleed
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Embolism and Thrombosis; Thromboembolism; Venous Thromboembolism; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Protease Inhibitors; Factor Xa Inhibitors; Antithrombins; Serine Proteinase Inhibitors; Rivaroxaban; Dabigatran; Apixaban; Edoxaban; Warfarin; Anticoagulants
• Other Study ID Numbers: X9001305; VTE HIRA Study (Other Identifier: Alias Study Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes