Retrospective Review of Appropriate Use of Antimicrobials and Anticoagulants in Patients Hospitalized for a Malignant Hematologic Condition
Authors: Porter Louis-Bassett , Shihadeh Hanaa , Dittus Kim 
Published: November 2019

Background
Interventions for venous thromboembolism (VTE) prophylaxis and primary antimicrobial prophylaxis for chemotherapy-induced neutropenia and hematopoietic stem cell transplant (HSCT) recipients have resulted in reduced rates of VTE and infection. Appropriate prevention of thrombosis and infection requires a day-to-day evaluation in hospitalized hematology patients experiencing changing chemotherapy regimens and fluctuating neutrophil or platelet counts. Inappropriate use of anticoagulants in patients with thrombocytopenia may result in iatrogenic bleeding.
Methods
To evaluate appropriate antimicrobial and anticoagulant prophylaxis, a retrospective extraction of electronic medical records of hematology inpatients meeting eligibility criteria from 06/2017 - 06/2018 was completed. Appropriate use was determined by the University of Vermont Medical Center's internal protocols, which are derived from the current standard of care. Anti-viral prophylaxis (AVP) is required for any hospital day for patients undergoing HSCT and was within 180 days of transplant, or having a diagnosis of acute myeloid leukemia (AML) or acute lymphocytic leukemia (ALL), while on induction, consolidation, or maintenance chemotherapy, or was receiving specific therapy (e.g., Hyper-CVAD, CODOX-M, R-DA-EPOCH, VD-PACE, bendamustine, alemtuzumab (stopping when CD4 count >200), proteosome inhibitors, or Daratumumab). Anti-pneumocystis prophylaxis (APP) is required for any hospital day for patients diagnosed with ALL (on induction, consolidation, or maintenance chemotherapy, or therapies listed above), receiving high dose steroids (prednisone >20 mg/day or dexamethasone >4 mg/day for 30 or more days), purine analogs (e.g., fludarabine, clofarabine) or undergoing HSCT (after platelet engraftment). Antimicrobial prophylaxis was considered inappropriate when the above conditions were met but the patient was not provided the appropriate therapy during an inpatient day and did not have a documented contraindication. Anticoagulant prophylaxis (ACP) was considered inappropriate when an anticoagulant was provided on a hospital day when platelets were less than 50 K/cmm. Days where the patient missed a dose at admission or discharge were excluded.
Results
We evaluated a total of 221 patient visit records comprised of 142 unique patients. In total, on 189 (10.9%) of 1,734 total inpatient days evaluated, appropriate antimicrobial prophylaxis was not provided (Table 1). Regarding AVP, 15 (6.8%) patients missed at least one day, a total of 69 (4.0%) days. 11 (5.0%) patients missed at least one day of APP, a total of 120 (6.9%) days. Regarding ACP, there are 1,961 platelet count observations which included 219 visits from 140 unique patients (Table 2). Of these observations, 603 (30.8%) had platelet counts below 50 K/cmm. ACP was not held 18 times (3.0%) when platelet levels fell below 50 K/cmm. 51 patients (36.4%) had their platelets drop below 50 K/cmm at some point during their visit(s) of which 7 (13.7%) did not have ACP withheld.
Conclusions and Discussion
The results identify areas of improvement regarding antimicrobial prophylaxis. Antimicrobial prophylaxis is often not systematically evaluated on inpatient services and as such may not be consistently evaluated by clinicians rotating on the hematology service. Conversely, guidelines for withholding anticoagulant prophylaxis were more closely followed. This is likely due to the focus in recent years on anticoagulation prophylaxis and the near universal knowledge of bleeding risk when provided at low platelet levels. Inappropriate antithrombotic prophylaxis was most frequently noted at platelets of just below 50 K/cmm (i.e., 47-49 K/cmm) and immediately discontinued for following doses as platelet values declined. A potential intervention is the use of a daily checklist that can evaluate the use of these therapies.

Disclosures
No relevant conflicts of interest to declare.