OBJECTIVES: Excluding specific products, injectable anticoagulants (IAC) are mainly unfractionated heparin (UFH), low molecular weight heparins (LMWH) and fondaparinux (FDX). These products differ in their associated bleeding risks and platelet monitoring requirements.To estimate and cost the incidence of platelet monitoring and major bleedings associated to IAC in real life setting. METHODS: Data from a random sample of ≈ 600,000 individuals registered in the French national health insurances database (covering 90% of the population) were analyzed. Patients exposed to IAC were selected and treatment sequences identified over 2013. Platelet count frequency and rate of treatment sequences interrupted due to thrombocytopenia or transfusion were estimated. A binomial regression model was used to compare the results. Associated costs were calculated. RESULTS: Overall, 15,051 complete IAC treatment sequences (beginning/ending over the year 2013) were identified corresponding to 15,985 adult patients and 12,264 months of cumulated exposure (UFH 3.7%; LMWH: 85.5%; FDX: 10.8%). Patients receiving UFH were significantly different from other groups in terms of age (73 vs 56.1 and 57.3), gender (male: 54.8% vs 40.5% and 41.0 %), mean duration of sequences (32.6 vs 25.1 and 21 days). Average number of platelet counts per patient per month (pppm) were respectively 2.12; 2.75 and 0.72 (p <0.0001). No differences were observed among patients treated with LMWH and FDX considering sequences interrupted due to bleeding (0.013 and 0.009 pppm;p = 0.76) or due to thrombocytopenia (0.003 and 0.002 pppm;p = 0.82). Fitted results between the two groups did not change these findings. Nationally, platelet counts in patients treated with LMWH cost €21.6 million (€0.9 million in FDX patients). CONCLUSIONS: Results confirm that platelet counts were less frequently prescribed for patients receiving FDX as compared to LMWH without additional bleeding risk. Reducing the use of platelet counts may have a significant economic interest.