THE COST AND BENEFIT OF PROPHYLAXIS AGAINST DEEP-VEIN THROMBOSIS IN ELECTIVE HIP-REPLACEMENT

A consensus forum was convened to evaluate the economic considerations associated with prophylaxis against thrombo-embolic disease in patien ts undergoing hip replacement therapy in South Africa, This forum cons ists of orthopaedic surgeons, vascular surgeons and a statistician. Me thods. The forum was instructed to evaluate the economic costs of the commonly used forms of prophylaxis of thrombo-embolism in patients und ergoing hip replacement surgery in South Africa, looking at shortterm events only. The methods used for the prophylaxis of thrombo-embolism in South Africa were determined by a postal survey. A decision tree wa s constructed to determine the events that will occur after a clinical decision to use no prophylaxis. The probabilities of these events wer e then determined. Protocols for and costs of prophylaxis and treatmen t were established. With the decision tree and these costs, the cost o f the various modalities of prophylaxis was then determined. Results. The probability, determined by the forum, of developing a deep-vein th rombosis (DVT) when no prophylaxis is used was 0.5, with a mortality r ate of 2.1%, The cost of this decision was R875, No prophylaxis given, but a venogram performed on day 7, reduced the mortality rate to 0.7% ; however, this cost R3 017. The cost of low-molecular-weight heparin was R1 223 (probability 0.26, mortality rate 1.1%), while unfractionat ed heparin with a graduated compression stocking (GCS) cost R1 351 (pr obability 0.24, mortality rate. 1%). Aspirin with a GCS cost R777 (pro bability 0.35, mortality rate 1.5%). Conclusions. The use of some form of prophylaxis against DVT formation in patients undergoing elective hip replacement in South Africa is mandatory, as all the methods commo nly used reduced the mortality. The use of no prophylaxis but with scr eening for DVT at day 7 - 10 is not justified as it is very expensive. Aspirin in combination with a stocking is the cheapest form of prophy laxis, but does not reduce the prevalence of DVT and does not reduce m ortality sufficiently to be clinically effective. The heparins (possib ly in combination with stockings) appear to be most cost-effective but cost between R350 and R500 more per patient than when no prophylaxis is used.