The implementation of NICE guidance on venous thromboembolism risk assessment and prophylaxis: A before- after observational study to assess the impact on patient safety across four hospitals in England.

Introduction: Venous thromboembolism (VTE) is a major cause of morbidity and mortality in hospitalised patients. VTE prevention has been identified as a major health need internationally to improve patient safety. A National Institute for Health and Clinical Excellence (NICE) guideline was issued in February 2010. Its key priorities were to assess patients for risk of VTE on admission to hospital, assess patients for bleeding risk and evaluate the risks and benefits of prescribing VTE prophylaxis. Objectives: To evaluate the implementation of NICE guidance and its impact on patient safety. Design: Before and after observational study design was used to investigate changes in VTE risk assessment documentation and inappropriate prescribing of prophylaxis between the year prior to (2009) and the year following (2010) the implementation of NICE guidance. A total of 816 patients were sampled in each year in four hospitals in the NHS South region. Results: The percentage of patients for whom a VTE risk assessment was documented increased from 51.5% (210/408) in 2009 to 79.2% (323/408) in 2010; difference 27.7% (95% CI: 21.4% to 33.9%; p<0.001). There was little evidence of change in the percentage who were prescribed prophylaxis amongst patients without a risk assessment (71.7% (142/198) in 2009 and 68.2% (58/85) in 2010; difference -3.5%% (95% CI: -15.2% to 8.2%; p =0.56) nor the percentage who were prescribed low molecular weight heparin amongst patients with a contraindication (14% (4/28) in 2009 and 15% (6/41) in 2010; RD = 0.3% (95% CI: -16.5% to 17.2%; p =0.97). Conclusions: The documentation of risk assessment improved following the implementation of NICE guidance but this did not lead to improved patient safety when prescribing prophylaxis.