[Comparison of platelet monitoring in patients receiving thromboprophylaxis with fondaparinux or a low molecular weight heparin. The Ariane study]

Abstract

Objective: To describe and compare the conditions of use of fondaparinux and low molecular weight heparin (LMWH) in the prevention of venous thromboembolism in routine general practice with a focus on platelet monitoring.

Method: This was an observational and pharmaco-epidemiological survey, performed in France in general practice in adult patients receiving thromboprophylaxis with fondaparinux or a LMWH. The study collected data on medical conditions justifying thromboprophylaxis, reasons for platelet monitoring and type of prescription.

Results: Four hundred and seventy general practioners included 837 analysable patients (450 treated with fondaparinux and 387 with LMWH). In the fondaparinux group, the mean age was 61.5±17.3 and 259 (57.6 %) patients were women. In the LMWH group, the mean age was 61.7±17.8 and 205 (53.0 %) patients were women. The reasons of prescribing were: bedridden related to a severe acute medical illness in 255 (56.7 %) patients with fondaparinux and 244 (63.1 %) with LMWH, and reduction of mobility associated with trauma without fracture respectively in 121 (26.9 %) and 85 (22.0 %) of patients. Associated risk factors were varicose veins, obesity and a history of thrombosis. Platelet monitoring was prescribed in 168 (37.6 %) patients treated with fondaparinux. In this group, these prescription were considered "appropriate" in 94 (20.9 %) patients, of whom 76 (16.9 %) were monitored for screening purposes, and "not appropriate" in 67 (14.9 %) patients, because prescribed to monitor thrombo-prophylaxis. In the LMWH group, a platelet count was prescribed in 370 (96.1 %) patients, of whom 312 (81.0 %) receiving a prescription only in order to monitor thromboprophylaxis.

Discussion: The results provided in the Ariane study were coherent with literature data (Etape and Depart studies). In comparison with the CNAM study, which evaluated prescription practices for LMWH in thromboprophylaxis in France in 1999, and which reported a global rate of platelet monitoring of 70.0 %, the rate reported in the Ariane study (81.0 %) seems to represent an improvement in the practice standards. Since 2009, Afssaps does not recommend a systematic monitoring with LMWH at acute or prophylactic dose, outside a post surgical context or in case of pre-treatment with unfractionated heparin.

Conclusion: The Ariane study provides important information on platelet monitoring in patients treated with fondaparinux or LMWH, and also on thromboprohylaxis in general practice.