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Clinical Trial Details — Status: Completed

Administrative data

NCT number NCT01178333
Other study ID # 678
Secondary ID U01HL072268
Status Completed
Phase N/A
First received August 6, 2010
Last updated May 6, 2015
Start date June 2010
Est. completion date December 2010

Study information

Verified date March 2013
Source New England Research Institutes
Contact n/a
Is FDA regulated No
Health authority United States: Federal Government
Study type Observational

Clinical Trial Summary

HIT-RADIO is a study of patients who had a positive heparin PF-4 antibody test between 1/21/2008 and 9/25/2008 at selected hospitals. The study will collect and analyse information that is already in the patients' medical records. Information about laboratory values (such as platelet counts), treatments (such as medications), and outcomes (such as blood clots, amputation, and death) will be included.


Description:

HIT-RADIO is a retrospective chart-review study of patients who had a positive heparin PF-4 antibody test between 1/21/2008 and 9/25/2008 at selected hospitals associated with the Transfusion Medicine/Hemostasis Clinical Trials Network .

Heparin-induced thrombocytopenia (HIT) is a major complication of the administration of heparin and can result in life-threatening thrombosis with or without thrombocytopenia (HIT-T) or can produce thrombocytopenia without clinically symptomatic thrombosis ("isolated" HIT). Isolated heparin-induced thrombocytopenia is defined as a fall in platelet count associated with a positive heparin PF-4 antibody test, in the absence of clinically overt thrombosis. While the treatment of HIT-T (HIT with thrombosis) with anticoagulation is well established, the risks and treatment of isolated HIT are unclear.

It is anticipated that this data analysis will provide a current overview of the implications of a positive heparin PF-4 antibody test in clinical practice. It should determine the percentage of positive heparin PF-4 antibody tests that are associated with thrombocytopenia and thrombosis (HIT-T) or "isolated" HIT at diagnosis and the subsequent major clinical outcomes of death, limb amputation/gangrene, and new thrombosis. No "snapshot" of such HIT patients has been conducted in the past decade and the results will be important in assessing the impact of HIT in current medical care as well as documenting current treatment strategies.


Recruitment information / eligibility

Status Completed
Enrollment 668
Est. completion date December 2010
Est. primary completion date December 2010
Accepts healthy volunteers No
Gender Both
Age group N/A and older
Eligibility Inclusion Criteria:

- All subjects with a positive heparin PF-4 antibody test occurring between 1/21/2008 and 9/25/2008

- Medical record available for the admission during which the positive heparin PF-4 antibody test was obtained

Exclusion Criteria:

Study Design

Observational Model: Case-Only, Time Perspective: Retrospective


Locations

Country Name City State
United States Johns Hopkins Baltimore Maryland
United States University of Maryland Greenebaum Cancer Center Baltimore Maryland
United States Beth Israel Deaconess Medical Center Boston Massachusetts
United States Brigham and Women's Hospital Boston Massachusetts
United States Children's Hospital, Boston Boston Massachusetts
United States Massachusetts General Hospital Boston Massachusetts
United States University of North Carolina, Chapel Hill Chapel Hill North Carolina
United States Case Western Reserve University School of Medicine Cleveland Ohio
United States Cleveland Clinic Cleveland Ohio
United States Duke University Medical Center Durham North Carolina
United States University of Iowa Iowa City Iowa
United States Gunderson Clinic LaCrosse Wisconsin
United States University of Wisconsin Comprehensive Cancer Center Madison Wisconsin
United States Froedtert Milwaukee Wisconsin
United States St. Luke's Medical Center Milwaukee Wisconsin
United States University of Minnesota Minneapolis Minnesota
United States Tulane University New Orleans Louisiana
United States Cornell University New York New York
United States University of Pennsylvania Philadelphia Pennsylvania
United States University of Pittsburgh Pittsburgh Pennsylvania
United States Fred Hutchinson Cancer Research Center Seattle Washington

Sponsors (2)

Lead Sponsor Collaborator
New England Research Institutes National Heart, Lung, and Blood Institute (NHLBI)

Country where clinical trial is conducted

United States, 

Outcome

Type Measure Description Time frame Safety issue
Primary Time to Occurrence of a Composite Triple Endpoint Consisting of Death, Limb Amputation/Gangrene, and New Thrombosis The mean time to an event is estimated by the area under the survival function. If the largest time is an event time, then the survival function goes to zero at that time, and the mean survival estimate is finite. Otherwise, the mean time cannot be estimated and may lead to a bias. From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge or day 45, whichever occurred first. No
Primary Time to Occurrence of a Composite Triple Endpoint Consisting of Death, Limb Amputation/Gangrene, and New Thrombosis The median survival time is reported by each group for the time to occurrence of a composite triple endpoint consisting of death, limb amputation/gangrene, and new thrombosis. From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge or day 45, whichever occurred first. No
Secondary Time to Death The mean time to an event is estimated by the area under the survival function. If the largest time is an event time, then the survival function goes to zero at that time, and the mean survival estimate is finite. Otherwise, the mean time cannot be estimated and may lead to a bias. From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Death The median survival time is reported by each group for the time to death. From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Occurrence of Limb Amputation or Limb Gangrene Due to the small number of events, the median or mean survival time could not be defined. Therefore, the number of subjects with limb amputation or limb gangrene was reported in "Outcome Measure Data Table". From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Occurrence of Radiographically Confirmed Thromboembolism The mean time to an event is estimated by the area under the survival function. If the largest time is an event time, then the survival function goes to zero at that time, and the mean survival estimate is finite. Otherwise, the mean time cannot be estimated and may lead to a bias. However, the median survival times could not be defined for all three groups, so the mean time was reported in "Outcome Measure Data Table". From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Occurrence of Major Bleeding The mean time to an event is estimated by the area under the survival function. If the largest time is an event time, then the survival function goes to zero at that time, and the mean survival estimate is finite. Otherwise, the mean time cannot be estimated and may lead to a bias. From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Occurrence of Major Bleeding The median survival time is reported by each group for the time to occurrence of major bleeding. From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Proportion of Subjects With HIT With Thrombosis (HIT-T) and Isolated HIT Proportion of subjects who, at the time the positive heparin PF-4 antibody test was drawn, were in each of the following categories:
Group 1: Those with thrombosis and or without thrombocytopenia (HIT-T): 16% of 442 subjects.
Group 2: Those with thrombocytopenia but not thrombosis (Isolated HIT): 64% of 442 subjects.
Group 3: Those with neither thrombocytopenia nor thrombosis (Neither HIT-T nor Isolated HIT): 20% of 442 subjects.
From the date 5 days before the positive heparin PF-4 antibody test was drawn to the date it was drawn No
Secondary Type of Heparin Exposure - Unfractionated Heparin (UFH) Two types of heparins are commonly used as anticoagulants - unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH). UFH has been used for the prevention and treatment of thrombosis for several decades. Hospital admission to date the positive heparin PF-4 antibody test was drawn, or 28 days prior to the date it was drawn, whichever is later, through the date it was drawn No
Secondary Type of Heparin Exposure - Low Molecular Weight Heparin (LMWH) Two types of heparins are commonly used as anticoagulants - unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH). LMWHs are derived from UFH by depolymerization. Each LMWH product has a specific molecular weight distribution that determines its anticoagulant activity and duration of action. Hospital admission to date the positive heparin PF-4 antibody test was drawn, or 28 days prior to the date it was drawn, whichever is later, through the date it was drawn No
Secondary Relationship of the Heparin PF-4 (Platelet Factor 4) Antibody Titer to the Clinical Diagnosis Heparin PF-4 (platelet factor 4) optical density (OD) test results were the dichotomous outcome (<1.0 vs. >=1.0). Clinical diagnosis was three groups (HIT-T, Isolated HIT and No HIT). The Heparin PF-4 optical density test looks for antibodies to complexes of heparin combined with platelet factor 4. Higher optical density indicates higher antibody concentration. We could say that generally OD values above 0.4 are considered a positive result, and that the higher the OD, the greater the concentration of antibodies in the patient's blood. From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Relationship of the Heparin PF-4 Antibody Titer to the Degree of Thrombocytopenia Heparin PF-4 optical density (OD) test results were the dichotomous outcome (<1.0 vs. >=1.0). Nadir Platelet Count (x10^9 / L) was used for the degree of thrombocytopenia. The Heparin PF-4 optical density test looks for antibodies to complexes of heparin combined with platelet factor 4. Higher optical density indicates higher antibody concentration. We could say that generally OD values above 0.4 are considered a positive result, and that the higher the OD, the greater the concentration of antibodies in the patient's blood. From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Relationship of the Heparin PF-4 Antibody Titer to the Primary Endpoint Heparin PF-4 OD test results were the dichotomous outcome (<1.0 vs. >=1.0). Primary endpoint was the composite endpoint of death, limb amputation/gangrene, or new thrombosis. From the time the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Use of Treatment (Non-heparin Anticoagulant) Used in Hospital Types of treatment (direct thrombin inhibitor, fondaparinux, warfarin, no treatment) provided to subjects in hospital From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Use of Treatment (Non-heparin Anticoagulant) Used at the Time of Discharge From the time that the positive heparin PF-4 antibody test was drawn until hospital discharge, death, or day 45, whichever occurred first No
Secondary Time to Platelet Recovery, Among Subjects With a Low Platelet Count When the Positive PF4 Antibody Test Was Drawn From the time that the nadir platelet count was drawn until hospital discharge, death, or day 45, whichever occurred first No
See also
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Recruiting NCT05785819 - A Phase 2 Study of VLX-1005 Versus Placebo in Suspected Heparin Induced Thrombocytopenia Phase 2