Medicine Utilization Review of Heparin at Kenyatta National Hospital

Abstract

Background Unfractionated heparin and low molecular weight heparins are effective anticoagulant options for prevention and treatment of thrombosis in diverse clinical settings. However heparin anticoagulation has potential for serious adverse effects which include heparin induced hemorrhage, heparin induced thrombocytopenia, osteopenia and electrolyte disturbances. Evaluation of individual patient benefit-risk profile is critical in optimizing heparin anticoagulation and prevention of adverse effects associated with heparin. Individualization of therapy is achieved through careful risk stratification of patients before initiation of treatment and routine clinical and laboratory monitoring in the course of therapy. Objective The study aimed to assess the prescribing, clinical and laboratory monitoring of unfractionated heparin and enoxaparin, as well as establish the prevalence of heparin induced adverse effects at Kenyatta National Hospital (KNH). Methodology The study involved medicine utilization review (MUR) of unfractionated heparin (UFH) and enoxaparin based on predetermined criteria. The study was conducted at the medical, general surgical, orthopedic and cardiothoracic surgical wards and renal unit of Kenyatta National Hospital. The population studied included patients who were aged 18 years and above, hospitalized and who received UFH or enoxaparin. Descriptive data analysis was carried out to describe the study population. Categorical data was described as proportions and percentages while continuous data was summarized using means or medians. Data analysis also described the proportion of patients who met each one of the criteria set out in the MUR for both UFH and enoxaparin. Results: Unfractionated heparin was indicated for prevention of thrombosis in hemodialysis at KNH. Compliance with MUR performance threshold ranged from 0% for bridge therapy and

anticoagulant reversal criteria to 100% for justification of use, dosage, frequency and route of administration. Reported UFH induced adverse effects include bleeding episodes which occurred in 17.8% of patients. Reported clinical outcomes for patients who received UFH were recovery and discharge in 90.3% of the patients and all-cause mortality in 9.7% of the patients. Similarly 1.6% of the patients experienced hemorrhagic stroke. Majority of the patients (61, 84.7%) received enoxaparin for venous thromboembolism (VTE) prophylaxis. Four patients (5.6%) were offered enoxaparin for treatment of pulmonary embolism while the same was indicated for treatment of deep venous thrombosis in seven patients (9.7%). Enoxaparin was also indicated for atrial fibrillation in one patient (1.4%). Justification of use of enoxaparin was appropriate in all patients and met the performance compliance threshold of 100%. Bleeding was reported in 2.8% of patients who received enoxaparin. Clinical outcomes reported in these patients were recovery and discharge (69, 95.8%), all-cause mortality (3, 4.2%) and new thrombotic events (2, 2.8%). Compliance with MUR performance threshold in patients treated with enoxaparin varied between 0% for laboratory monitoring during therapy and bridge therapy criteria, and 100% for justification of enoxaparin use. Conclusions Medicine Utilization Review criteria were developed to assess the prescription practices and use of UFH/enoxaparin as well as to determine the range and extent of use of laboratory tests in monitoring of heparin use at KNH. The average compliance with the MUR criteria was minimal in patients who received UFH. Partial compliance with MUR criteria was observed in patients who received enoxaparin. This is in comparison with the set performance threshold of 100% for each criterion set out in the MUR. Significant bleeding episodes were reported among patients who received UFH at KNH. There is need to put interventions in place to ensure safe use of UFH and enoxaparin at KNH.