An economic evaluation of the costs and benefits of heparin rationalisation in a hospital pharmacy.

AIM: To estimate the costs and benefits for a UK hospital pharmacy of stocking a single low molecular weight heparin (LMWH), enoxaparin, compared to stocking unfractionated heparin (UFH) and stocking both UFH and multiple different LMWHs.

METHODS: A decision-tree model was developed which considered the use of heparins for five indications: prophylaxis against venous thromboembolism (VTE) in major orthopaedic surgery; VTE prophylaxis in major general surgery; VTE prophylaxis in acute medical inpatients; treatment of diagnosed VTE; and anticoagulation for patients with unstable angina and non-ST-elevation myocardial infarction (UA/NSTEMI). Previously published cost-effectiveness analyses for each indication were combined into a single model and updated to 2002 prices. The number of patients given heparin in each indication was estimated from the pharmacy records of a large UK teaching hospital. The model estimated the use of drugs, staff time, clinical events and resource use resulting from anti-coagulation. Costs were estimated from the perspective of the hospital and the UK National Health Service.

RESULTS: Total annual cost was estimated to be pounds sterling 3.2 m (single LMWH), pounds sterling 4.4 m (UFH only) and pounds sterling 3.7 m (multiple heparins). The largest expected cost savings from using a single LMWH compared to UFH only resulted from reduced hospital stay for DVT treatment, reduced revascularisation in UA/NSTEMI and fewer VTE events in orthopaedic surgery. Expected cost savings from using a single LMWH compared to multiple heparins were more modest

CONCLUSION: Sub-optimal choice of anticoagulants may result in substantial excess costs elsewhere in the hospital.