An Observational Study on Incidence, Natural History and Treatment Patterns of Venous Thromboembolism in Taiwan

Study Overview
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Brief Summary
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The research question addressed by this study is primarily on the clinical epidemiology of VTE in Taiwan. The study aims to estimate the incidence of VTE and describe natural history of VTE, including long term clinical outcomes in adult Taiwanese population, utilizing population-based electronic health data in Taiwan.

Official Title
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An Observational Study on Incidence, Natural History and Treatment Patterns of Venous Thromboembolism in Taiwan

Conditions
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Venous Thromboembolism

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The source population was the adult population in Taiwan. The legal age for definition as an adult (without additional research ethics review requirement) in Taiwan is 20; therefore all National Health Insurance (NHI) enrollees age 20 or older at any time during the study period were evaluated for VTE. Exclusion Criteria: Person-time before an eligible subject turned 20 were not evaluated. Study subjects having inconsistent data on gender and unrealistic date of birth (birth year before 1890 and after 2015) were identified and excluded from the analysis.

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incident VTE | Incident VTE cases were those who had a first VTE diagnosis after 1 January 2005 and with at least 5 years of look-back period. Those with a first VTE diagnosis less than 5 years of look-period were considered as undetermined VTE cases. | 4 years | 
| Potential risk factors that occurred before the incident VTE events | Events during the 3 months before the first VTE recurrence will be described. Potential risk factors that will be evaluated include age, gender, and treatment regimen for VTE, adherence to treatment regimen, concomitant medications, and comorbidity. The analysis will be stratified by the nature of the first VTE (provoked and unprovoked). Due to the unknown number of repeated recurrence and complex clinical nature of patients with multiple VTE recurrence, risk factors for multiple recurrences will be evaluated at a less detailed level than that for the first recurrence. | 4 years | 
| Usage patterns of anticoagulants among incident VTE patients were evaluated during incident VTE hospital admission and after discharge |  | 4 years | 
| All-cause mortality | All deaths before 31 December 2014 among the incident VTE patients were identified through the mortality records. Patients were followed from incident VTE index date, and the patients were censored on 31 December 2014 or termination of NHI coverage without further medical or mortality records. If the patient died during the same hospitalization during the incident VTE, the death date was defined as the discharge date of that specific hospitalization. | 4 years | 
| Major bleeding | Major bleeding (intracranial bleed and gastrointestinal bleed) was the major morbidity of interest and incident VTE patients were followed from incident VTE index date till 31 December 2014, death or termination of NHI coverage without any further medical records. Patients died during the incident VTE hospitalization were excluded for major bleeding follow up. | 4 years | 
| Recurrent VTE | Recurrent VTE events after the incident VTE diagnosis were evaluated during the follow-up period through 31 December 2014 or until the patient died or NHI coverage terminated without any further medical records after the termination. The same VTE operational definitions according to different algorithm in incident VTE were consistently applied in recurrent VTE. | 4 years | 
| Adherence of oral anticoagulant treatment was also evaluated with the calculation of MPR within 6 months and 12 months after discharge. |  | Up to 6 and 12 month |