The Comparative Safety and Effectiveness of Warfarin and Dabigatran Prescribed in the Non-valvular Atrial Fibrillation Population With Humana Healthcare Coverage

Atrial Fibrillation Clinical Trial

Official title:

The Comparative Safety and Effectiveness of Warfarin and Dabigatran Utilized in the Humana Non-Valvular Atrial Fibrillation (NVAF) Patient Population-A Retrospective Database Analysis

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02061748
• Other study ID #: 1160.192
• Status: Completed
• Phase: N/A
• First received: February 12, 2014
• Last updated: June 7, 2017
• Start date: October 28, 2014
• Est. completion date: March 15, 2016

Study information

• Verified date: June 2017
• Source: Boehringer Ingelheim
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

This study is an opportunity for Boehringer Ingelheim to collaborate with Humana to conduct comparative safety and effectiveness studies of dabigatran and warfarin using real world data from Humana's health plan operations.

Description:

Study Design:

Recruitment information / eligibility

• Status: Completed
• Enrollment: 38499
• Est. completion date: March 15, 2016
• Est. primary completion date: March 15, 2016
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 89 Years

Eligibility

Inclusion criteria:

• Patient must have at least one inpatient, one physician office visit, or one emergency room visit with a diagnosis of AF on the index date or during the pre-index period.

• Patients must be continuously enrolled in a health plan during the pre-index period

• Patient must have a prescription for dabigatran or warfarin

• Patient must be treatment naive from all oral anticoagulant (OAC) use prior to first OAC prescription

• Aged 18-89 years on the index date. The index date is defined as the date of the first OAC prescription

Exclusion criteria:

• Diagnosis of hyperthyroidism during the pre-index period,

• Having claims for any of the following within 3 months prior to the first diagnosis of AF: cardiac surgery, pericarditis, myocarditis, pulmonary embolism.

• Any patients with at least one medical claim for valvular heart disease.

Related Conditions & MeSH terms

• Atrial Fibrillation

Intervention

Drug:
• Observational
Retrospective Chart Review

Locations

Country	Name	City	State
United States	Comprehensive Health Insights, Louisville	Louisville	Kentucky

Sponsors (1)

Lead Sponsor	Collaborator
Boehringer Ingelheim

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Stroke (Primary Analysis)	This outcome measure describes the incidence of stroke (hemorrhagic and ischemic) for dabigatran and warfarin in the primary analysis.; Ischemic stroke includes: Occlusion and stenosis of precerebral arteries with cerebral infarction, Occlusion of cerebral arteries with cerebral infarction and Acute, but ill-defined, cerebrovascular disease but excludes above diagnosis if hospitalization lasted less than 48 hours and was accompanied by carotid endarterectomy.; Hemorrhagic stroke includes: Subarachnoid hemorrhage (SAH) and Intracerebral hemorrhage (ICH) but excludes previous listed diagnoses if "traumatic brain injury" or "rehabilitation care" is present.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Primary	Stroke (Post-hoc Analysis)	This outcome measure describes the incidence of stroke (hemorrhagic and ischemic) for dabigatran and warfarin in the post-hoc analysis. A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Primary	Major Bleeding (Primary Analysis)	This outcome measure describes the incidence of major bleeding (hemorrhagic stroke, major intracranial bleeding and major extracranial bleeding) for dabigatran and warfarin in the primary analysis.; Major Intracranial Bleeding includes subarachnoid hemorrhage, intracerebral hemorrhage, other and unspecified intracranial hemorrhage, subarachnoid hemorrhage following injury without mention of open intracranial wound, subdural hemorrhage following injury without mention of open intracranial wound, extradural hemorrhage following injury without mention of open intracranial wound, other and unspecified intracranial hemorrhage following injury without mention of open intracranial wound but excludes these codes if major trauma was present. Major extracranial bleeding includes major gastrointestinal (GI) bleeding, major urogenital bleeding and major other bleeding. Either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization were used.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Primary	Major Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major bleeding (Inclusive of hemorrhagic stroke, major intracranial bleeding and major extracranial bleeding) for dabigatran and warfarin in the post-hoc analysis. A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Ischemic Stroke (Primary Analysis)	This outcome measure describes the incidence of ischemic stroke for dabigatran and warfarin in the primary analysis. Ischemic stroke includes: Occlusion and stenosis of precerebral arteries with cerebral infarction, Occlusion of cerebral arteries with cerebral infarction and Acute, but ill-defined, cerebrovascular disease but excludes above diagnosis if hospitalization lasted less than 48 hours and was accompanied by carotid endarterectomy.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Ischemic Stroke (Post-hoc Analysis)	This outcome measure describes the incidence of ischemic stroke for dabigatran and warfarin in the post-hoc analysis. Ischemic stroke includes: Occlusion and stenosis of precerebral arteries with cerebral infarction, Occlusion of cerebral arteries with cerebral infarction and Acute, but ill-defined, cerebrovascular disease but excludes above diagnosis if hospitalization lasted less than 48 hours and was accompanied by carotid endarterectomy.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Hemorrhagic Stroke (Primary Analysis)	This outcome measure describes the incidence of hemorrhagic stroke for dabigatran and warfarin in the primary analysis. Hemorrhagic stroke includes: subarachnoid hemorrhage, intracerebral hemorrhage but excludes these codes if "traumatic brain injury" or "rehabilitation care" as primary code is present.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Hemorrhagic Stroke (Post-hoc Analysis)	This outcome measure describes the incidence of hemorrhagic stroke for dabigatran and warfarin in the post-hoc analysis. Hemorrhagic stroke includes: Subarachnoid hemorrhage and intracerebral hemorrhage but excludes these codes if "traumatic brain injury" or "rehabilitation care" as primary code is present.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Intracranial Bleeding (Primary Analysis)	This outcome measure describes the incidence of major intracranial bleeding for dabigatran and warfarin in the primary analysis. Major intracranial bleeding includes: Subarachnoid hemorrhage, intracerebral hemorrhage, other and unspecified intracranial hemorrhage, subarachnoid, subdural or extradural hemorrhage following injury without mention of open intracranial wound other and unspecified intracranial hemorrhage following injury without mention of open intracranial wound but excludes these codes if concomitant discharge diagnosis of major trauma was present.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Intracranial Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major intracranial bleeding for dabigatran and warfarin in the post-hoc analysis. Major intracranial bleeding includes: Subarachnoid hemorrhage, intracerebral hemorrhage, other and unspecified intracranial hemorrhage, subarachnoid, subdural or extradural hemorrhage following injury without mention of open intracranial wound other and unspecified intracranial hemorrhage following injury without mention of open intracranial wound but excludes these codes if concomitant discharge diagnosis of major trauma was present.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Extracranial Bleeding (Primary Analysis)	This outcome measure describes the incidence of major extracranial bleeding for dabigatran and warfarin in the primary analysis. Major extracranial bleeding includes: major gastrointestinal (GI) bleeding, major urogenital bleeding and major other bleeding.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Extracranial Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major extracranial bleeding for dabigatran and warfarin in the post-hoc analysis. Major extracranial bleeding includes: major gastrointestinal (GI) bleeding, major urogenital bleeding and major other bleeding.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major GI Bleeding (Primary Analysis)	This outcome measure describes the incidence of major GI bleeding for dabigatran and warfarin in the primary analysis. Major GI bleeding includes major upper GI bleeding and major lower GI bleeding.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major GI Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major GI bleeding for dabigatran and warfarin in the post-hoc analysis. Major GI bleeding includes major upper GI bleeding and major lower GI bleeding.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Upper GI Bleeding (Primary Analysis)	This outcome measure describes the incidence of major upper GI bleeding for dabigatran and warfarin in the primary analysis. Major upper GI bleeding includes acute gastric ulcer, chronic or unspecified gastric ulcer, acute duodenal ulcer, chronic or unspecified duodenal ulcer, acute, chronic or unspecified peptic ulcer, acute gastrojejunal ulcer, chronic or unspecified gastrojejunal ulcer with hemorrhage with/without obstruction and with hemorrhage and perforation with/without obstruction, hematemesis, endoscopic control of gastric or duodenal bleeding, upper gastrointestinal endoscopy including esophagus, stomach, and either the duodenum and/or jejunum as appropriate with control of bleeding, any method. Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Upper GI Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major upper GI bleeding for dabigatran and warfarin in the post-hoc analysis. Major upper GI bleeding includes acute, chronic or unspecified gastric ulcer, acute duodenal ulcer, chronic or unspecified duodenal ulcer, acute, chronic or unspecified peptic ulcer, acute, chronic or unspecified gastrojejunal ulcer with hemorrhage with/without (w/wo) obstruction and with hemorrhage and perforation w/wo obstruction, hematemesis, endoscopic control of gastric or duodenal bleeding, upper gastrointestinal endoscopy including esophagus, stomach, and either the duodenum and/or jejunum as appropriate with control of bleeding, any method. A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. This was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Lower GI Bleeding (Primary Analysis)	This outcome measure describes the incidence of major lower GI bleeding for dabigatran and warfarin in the primary analysis. Major lower GI bleeding includes diverticulosis or diverticulitis of small intestine or of colon with hemorrhage, hemorrhage of rectum and anus, angiodysplasia of intestine with hemorrhage, blood in stool and hemorrhage of GI tract (unspecified).; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Lower GI Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major lower GI bleeding for dabigatran and warfarin in the post-hoc analysis.; Major lower GI bleeding includes diverticulosis or diverticulitis of small intestine or of colon with hemorrhage, hemorrhage of rectum and anus, angiodysplasia of intestine with hemorrhage, blood in stool and hemorrhage of GI tract (unspecified).; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Urogenital Bleeding (Primary Analysis)	This outcome measure describes the incidence of major urogenital bleeding for dabigatran and warfarin in the primary analysis. Major urogenital bleeding includes hematuria and excessive/frequent menstruation and secondary diagnosis indicating acute bleeding (anemia).; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Major Urogenital Bleeding (Post-hoc Analysis)	This outcome measure describes the incidence of major urogenital bleeding for dabigatran and warfarin in the post-hoc analysis.; Major urogenital bleeding includes hematuria and excessive/frequent menstruation and secondary diagnosis indicating acute bleeding (anemia).; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Other Major Bleeds (Primary Analysis)	This outcome measure describes the incidence of other major bleeds for dabigatran and warfarin in the primary analysis. Other major bleeds includes hemarthrosis, hemopericardium, hemoptysis, epistaxis, hemorrhage (not specified) and acute posthemorrhagic anemia.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Other Major Bleeds (Post-hoc Analysis)	This outcome measure describes the incidence of other major bleeds for dabigatran and warfarin in the post-hoc analysis.; Other major bleeds includes hemarthrosis, hemopericardium, hemoptysis, epistaxis, hemorrhage (not specified) and acute posthemorrhagic anemia.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Transient Ischemic Attack (TIA) (Primary Analysis)	This outcome measure describes the incidence of TIA for dabigatran and warfarin in the primary analysis. TIA includes transient cerebral ischemia as the principal (primary) discharge diagnosis.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	TIA (Post-hoc Analysis)	This outcome measure describes the incidence of TIA for dabigatran and warfarin in the post-hoc analysis.; TIA includes transient cerebral ischemia as the principal (primary) discharge diagnosis.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Myocardial Infarction (MI) (Primary Analysis)	This outcome measure describes the incidence of MI for dabigatran and warfarin in the primary analysis. MI includes the acute myocardial infarction. Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	MI (Post-hoc Analysis)	This outcome measure describes the incidence of MI for dabigatran and warfarin in the post-hoc analysis.; MI includes the acute myocardial infarction. A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Venous Thromboembolism (Primary Analysis)	This outcome measure describes the incidence of venous thromboembolism for dabigatran and warfarin in the primary analysis. Venous thromboembolism includes the deep vein thrombosis and the pulmonary embolism.; Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Venous Thromboembolism (Post-hoc Analysis)	This outcome measure describes the incidence of venous thromboembolism for dabigatran and warfarin in the post-hoc analysis.; Venous thromboembolism includes the deep vein thrombosis and the pulmonary embolism.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Deep Vein Thrombosis (Primary Analysis)	This outcome measure describes the incidence of deep vein thrombosis for dabigatran and warfarin in the primary analysis. Deep vein thrombosis includes phlebitis and thrombophlebitis and other venous embolism and thrombosis. Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Deep Vein Thrombosis (Post-hoc Analysis)	This outcome measure describes the incidence of deep vein thrombosis for dabigatran and warfarin in the post-hoc analysis.; Deep vein thrombosis includes phlebitis and thrombophlebitis and other venous embolism and thrombosis.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Pulmonary Embolism (Primary Analysis)	This outcome measure describes the incidence of pulmonary embolism for dabigatran and warfarin in the primary analysis. Pulmonary embolism includes acute pulmonary heart disease. Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	Pulmonary Embolism (Post-hoc Analysis)	This outcome measure describes the incidence of pulmonary embolism for dabigatran and warfarin in the post-hoc analysis.; Pulmonary embolism includes acute pulmonary heart disease. A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	All-cause Death (Primary Analysis)	This outcome measure describes the incidence of death for dabigatran and warfarin in the primary analysis. Study outcomes for this analysis were identified using either the admitting diagnoses or on any of the service lines associated with an inpatient hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)
Secondary	All-cause Death (Post-hoc Analysis)	This outcome measure describes the incidence of death for dabigatran and warfarin in the post-hoc analysis.; A post-hoc analysis was conducted that measured outcomes using an algorithm to define the principal diagnosis. The principal diagnosis was defined as the primary diagnosis on the first room and board charge record within a hospital admission. This method results in identification of a single outcome for a hospitalization.	From 1 October 2010 to 30 April 2013 identified with index date (first prescription of dabigatran or warfarin) plus a follow-up period of 12 months (up to 42 months)

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