Clinical trial NCT00946400: Validating 4Ts for Heparin Induced Thrombocytopenia (HIT)
Official title: Prospectively Validating the 4Ts and Chong Score for Heparin Induced Thrombocytopenia
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Heparin-Induced Thrombocytopenia
Keywords: Heparin-induced thrombocytopenia
HIT
4Ts
Chong scale
interobserver variability
Lead sponsor: Medstar Health Research Institute
Sponsor class: OTHER
Collaborators: name: GlaxoSmithKline
First posted: 2009-07-27
Enrollment: 500
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: For this study, patients already admitted to the hospital whose physician suspects the presence of HIT will be recruited for this study. Specifically, the trigger for recruitment include patients who have a HIT antibody test ordered.

Brief summary: The purpose of this study is to evaluate a scoring tool to help determine the presence of Heparin Induced Thrombocytopenia (HIT), which is an adverse reaction to heparin. We hypothesize that this scoring tool will be very useful in excluding patients who are suspected of having HIT.

Detailed description: HIT is an immune response to heparin that can result in thrombogenic thrombocytopenia. It is often a difficult diagnosis to make, and its diagnosis is dependent upon both clinical and serologic criteria. Due to this ambiguity, increased testing and treatment may occur until serologic test results return. Recently, scoring tools have been developed to assist with the diagnosis of this disease. However, these scoring tools have yet to be validated. Thus, we plan to conduct a prospective, observational study to validate two scoring tools, the 4Ts and the Chong scale, in the diagnosis of HIT.

In order to validate these scoring tools, two physicians will independently score the 4Ts and the Chong scale for all patients suspected of having HIT. These patients will be identified if a physician has ordered HIT antibody testing using the enzyme immunoassay (EIA) method. Confirmatory testing with a serotonin release assay (SRA) will also be performed.

Eligibility criteria: Inclusion Criteria:

* Patients with suspected HIT.

Exclusion Criteria:

* None.

Primary outcomes:
measure: To validate the 4Ts as a pretest probability tool for HIT.
timeFrame: End of study.
measure: To validate the Chong scale as a tool to determine the post-test probability for HIT.
timeFrame: End of study.
Secondary outcomes:
measure: To determine the inter-rater variability for scoring the 4Ts.
timeFrame: End of study.
measure: To determine the inter-rater variability for scoring the Chong scale.
timeFrame: End of study.
Other outcomes:
Locations:
city: Washington
country: United States
facility: Washington Hospital Center
state: District of Columbia
Study officials:
affiliation: Medstar Health Research Institute
name: Chee M Chan, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Medstar Health Research Institute
name: Andrew F Shorr, MD, MPH
role: STUDY_DIRECTOR
References:
citation: Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A. Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. J Thromb Haemost. 2006 Apr;4(4):759-65. doi: 10.1111/j.1538-7836.2006.01787.x.
citation: Chong BH, Chong JJ. Heparin-induced thrombocytopenia. Expert Rev Cardiovasc Ther. 2004 Jul;2(4):547-59. doi: 10.1586/14779072.2.4.547.
citation: Chan CM, Woods CJ, Warkentin TE, Sheppard JI, Shorr AF. The Role for Optical Density in Heparin-Induced Thrombocytopenia: A Cohort Study. Chest. 2015 Jul;148(1):55-61. doi: 10.1378/chest.14-1417.