Modifications of low-molecular weight heparin use in a French university hospital after implementation of new guidelines

Background: Previous studies performed in 1999 and 2000 showed frequent misuse of low-molecular weight heparins (LMWHs) in France, leading to an increasing risk of bleeding. In 2002, the French Medicine Agency (Agence Francaise de Seurite Sanitaire des Produits de Sante released guidelines on the prescription and monitoring of LMWH. This study assesses LMWH use before and after the implementation of these guidelines. Methods: We performed a 'pre and post' survey comparing data collected in 1999 (before guidelines) and in 2003 (1 year after guidelines) at a French university hospital. The same design and the same medical wards were used for both data-collection periods, and the data collected included patient characteristics, LWMH prescription information (daily dose, indication) and adverse drug reactions (ADRs). The main outcome was the frequency of prescription of LMWHs for curative treatment in patients with severe renal insufficiency, defined as having a creatinine clearance of <= 30 mL/min, estimated using the Cockroft formula. Results: The analysis was performed in 332 patients in 1999 and 566 in 2003. Despite a similar frequency of prescription of LMWHs as curative treatments, the frequency with which patients with severe renal insufficiency were exposed to a LMWH as a curative treatment decreased significantly from 3.0% in 1999 to 1.0% in 2003 (p = 0.03). Compared with patients treated in 1999, those treated in 2003 were younger, more likely to be men, with a higher bodyweight and a shorter duration of hospitalisation. The incidence of haemorrhagic ADRs significantly decreased, with an odds ratio of 0.26 (95% CI 0.09, 0.73) according to the results of a multiple logistic regression analysis. Conclusions: Our results show a better agreement of prescribing practice with contraindications and cautions about LMWH prescription in patients at risk following the introduction of guidelines on LWMHs. However, these data only reflect LMWH utilisation in a French university hospital. In order to assess the impact of the guidelines more widely, other studies should be performed, including studies in ambulatory care settings.