South African guidelines on venous thromboembolism.

To the Editor: We commend the excellent work by Jacobson et al. on behalf of the South African Society of Thrombosis and Haemostasis in producing a very necessary set of local guidelines on the management of venous thromboembolism (VTE).1 VTE is a major cause of morbidity and mortality, as highlighted recently by the United States Surgeon General.2 One important nuance worth noting, however, is the fact that warfarin may be started together with low-molecularweight heparin (LMWH) on day 1 of anticoagulation, and is supported by recent guidelines by the British Committee for Standards in Haematology and the American College of Chest Physicians (ACCP) who both agree that LMWH and warfarin should be started on the same day.3,4 The ACCP gives this recommendation their highest level of evidence, namely 1A. Evidence for this suggestion includes data from a randomised trial by Mohiuddin et al. showing decreased cost and morbidity in the group started earlier on warfarin.5 Leroyer et al. and Gallus et al. have both also shown decreased duration of hospitalisation with earlier initiation of warfarin.6,7 The ACCP also recommends that the duration of LMWH should be for a minimum of 5 days v. the 7 days suggested by Jacobson et al. This is in part based on at least one randomised trial showing similar efficacy in both arms.8 Although this may only result in a total difference of 4 doses of LMWH per patient, the long-term cost implications may be significant. Lastly, noting the narrow therapeutic window of warfarin, we believe that it is important to consider major risk factors for bleeding on anticoagulants, such as increased age, uncontrolled hypertension, alcohol, use of non-steroidal anti-inflammatory drugs, liver disease and peptic ulcer disease, before initiating therapy.9,10