Background: Knee surgery is a risk factor for thromboembolic disease. Prophylaxis reduces the risk of this condition.
Methods: Economic and health consequences of drugs preventing and treating thromboembolic disease in patients undergoing knee surgery from the institutional perspective (time horizon: 1 year) were estimated. The measures of effectiveness were: reduction in the number of cases (per 1,000 patients) of deep vein thrombosis, pulmonary embolism, hospital admissions and deaths. Transition probabilities were estimated by meta-analysis. The alternatives were: warfarin (reference), dalteparin, enoxaparin, nadroparin, unfractionated heparin + warfarin, and non-prophylaxis. Data on resources use and costs corresponds to the Instituto Mexicano del Seguro Social (IMSS). Acceptability curves were constructed.
Results: No prophylaxis implied three times higher cost ($18,835.10 versus $5,967.10) and less effectiveness in comparison with warfarin. The incremental cost-effectiveness ratios for enoxaparin were $3, $13, $17 and $3 per each additional case of deep vein thrombosis, pulmonary embolism, death and hospital admission avoided. Results of nadroparin and unfractionated heparin were inferior to warfarin (59.1% and 72.9% more costly and less effective in three measures of effectiveness, respectively). Dalteparin showed higher health outcomes and lower cost compared with warfarin (-20.6%). Dalteparin had a higher probability of being cost-effective than enoxaparin.
Discussion: thromboprophylaxis is a clinically and economically favorable alternative. The identification of a pharmacoeconomic profile of alternatives to perform it becomes relevant given the increasing pressure on institutional budgets.
Conclusions: Dalteparin would be a cost-saving alternative in thromboprophylaxis of patients undergoing knee surgery at IMSS.