Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse drug reaction to heparin products which results in a prothrombotic state. Heparin-induced thrombocytopenia generally occurs several days after the start of unfractionated heparin or low molecular weight heparin and is diagnosed based on clinical presentation, and presence of thrombocytopenia. HIT has an incidence of 0.1% to 5% and if recognized early can help prevent major complications. As of November 2014, the responsibility for documenting heparin allergies in the electronic medical record (EMR) has shifted from the physician/medical resident to the pharmacy resident. The purpose of this study is to compare the number, rate, and appropriateness of heparin allergy documentation in order to help decrease adverse medical events related to heparin.
Heparin-induced thrombocytopenia is a unique form of drug induced thrombocytopenia associated with increased clotting risk. The incidence of HIT ranges from 0.1% to 5%. Heparin-induced thrombocytopenia occurs when an antibody forms a complex with platelet factor 4 and heparin. This complex activates platelets which increases the risk of thrombus formation. Normally, HIT presents 5 to 14 days after exposure, but can occur with heparin exposure within the past 100 days. The presentation of HIT is often first suspected secondary to a decrease in platelet counts of 50% or more from baseline. At Rush University Medical Center (RUMC), HIT is diagnosed through a combination of clinical factors and laboratory tests. When HIT is first suspected, a 4T HIT score, which is used to estimate the probability of true HIT, is calculated. The following score ranges correspond to the probability of true HIT; score of 0-3 indicates a low probability, score of 4-5 indicates an intermediate probability, and a score of 6-8 indicates a high probability of true HIT. If the score indicates a likelihood of HIT, a HIT-Ab is sent off. This test has a sensitivity of more than 95% and a specificity of 74% to 86%. Accordingly, if this HIT-Ab test result is negative, HIT is ruled out. If the result is equivocal or positive, a confirmatory Serotonin Release Assay (SRA) test should be performed (sensitivity of 89% to 100% and a specificity of 88 % to 100%). Prior to 2014, there was no formal process for evaluation of patients with HIT. In November of 2014, an EMR tool was created in an effort to improve heparin allergy documentation and HIT management. This EMR tool prompts the medical team to perform the 4T score, displays the appropriate HIT labs, alternative anticoagulation strategies, instructs the nurse to apply an allergy bracelet, and notifies the pharmacy resident through the order verification queue. The pharmacy resident then performs an independent 4T score, discontinues all heparin products, documents the heparin allergy in the medical record, and assesses the need for alternative anticoagulation. Many studies have shown the value of the 4T HIT scoring system and the use of pharmacists in reducing the inappropriate use of alternative anticoagulation and unnecessary testing. Pharmacists have helped to improve patient outcomes and decrease costs associated with HIT. The purpose of this study is to evaluate the impact of an EMR tool and pharmacy residents on allergy documentation and the management of HIT.
Study Type
OBSERVATIONAL
Enrollment
128
Prior to 2014, there was no formal process for evaluation of patients with HIT. In November of 2014, an EMR tool was created in an effort to improve heparin allergy documentation and HIT management. This EMR tool prompts the medical team to perform the 4T score, displays the appropriate HIT labs, alternative anticoagulation strategies, instructs the nurse to apply an allergy bracelet, and notifies the pharmacy resident through the order verification queue. The pharmacy resident then performs an independent 4T score, discontinues all heparin products, documents the heparin allergy in the medical record, and assesses the need for alternative anticoagulation.
Rush University Medical Center
Chicago, Illinois, United States
Assess appropriate allergy documentation
1\. Completion of appropriate allergy documentation will include all of the following: a. Heparin allergy documented i. Pending result ii. Positive result b. Heparin allergy removed i. Negative result
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Administration of heparin products with pending HIT-Ab
a. Defined as ordering of HIT-Ab or 4T score greater than 5 i. Low Probability: 0-3 ii. Intermediate Probability: 4-5 iii. High Probability: 6-8
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Documentation of 4T HIT score in patient medical record
Defined as documentation in a patient medical note, i-vent, or lab result
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Initiation or withholding of Direct Thrombin Inhibitor (DTI) appropriate based on probability of HIT as scored by the 4T HIT score
1. Initiation appropriate for 4T HIT score of greater than 5 2. Withholding appropriate for 4T HIT score of 3 or less (in absence of clot)
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Number of Serotonin Release Assay labs drawn appropriately
1. Appropriate defined as drawn secondary to a positive HIT-Ab 2. Inappropriate defined as drawn prior to ordering a HIT-Ab
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Positive and negative predictive value of 4T score when performed by medical resident
1. The percent of all positive tests that are true positives is the Positive Predictive Value. 2. The percent of all negative tests that are true negatives is the Negative Predictive Value
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
Positive and negative predictive value of 4T score when performed by pharmacy residents
1. The percent of all positive tests that are true positives is the Positive Predictive Value. 2. The percent of all negative tests that are true negatives is the Negative Predictive Value
Time frame: From the date of first ordering of a HIT-Ab until HIT allergy is determined as positive or negative, assessed up to 4 weeks
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