The case for formal stratification analysis when prescribing deep vein thrombosis prophylaxis.

Postoperative deep vein thrombosis (DVT) is common following general and orthopaedic surgery. Certain factors are known to increase the risk of DVT. To ascertain how surgeons use these factors to assess DVT risk and modify their DVT prophylaxis for individual cases, we circulated a questionnaire to 100 general and 200 orthopaedic surgeons. We inquired about whether DVT prophylaxis was used, and what risk factors were recognized, and we asked the surgeons to ascribe a level of DVT risk for five imaginary cases. All surgeons claimed to use prophylaxis. Most surgeons were largely aware of the accepted risk factors. There was, however, no consensus in allocating level of risk to individual imaginary cases. In conclusion, in spite of being aware of risk factors, similar patients are being dealt with in widely different ways by different clinicians. Therefore, we feel it is important to formally assess each individual patient's DVT risk and prescribe prophylaxis accordingly.