Practise what you preach? (David Gibson)

David Gibson

The Department of Health published thrombotic risk assessment tools in September 2008 and the National Institute for Health and Clinical Excellence has now published guidelines for the management of thromboembolic risk for hospital inpatients.

NICE and the DH recommend that all patients who are at risk of VTE should be offered thromboprophylaxis. In light of these new guidelines the acute trust I work for is in the process of improving its VTE policies. This has got me thinking about my role as a prescribing pharmacist for medical patients.

There are several large randomised controlled trials investigating VTE prophylaxis in medical patients. MEDENOX¹ and PREVENT² are the most widely cited. Although neither of these trials showed significant reductions in mortality rates, they did demonstrate reductions in the cumulative endpoint of pulmonary embolism, symptomatic deep vein thrombosis (DVT) and asymptomatic DVT.

These two trials reveal the benefits of low molecular weight heparin (LMWH) for thromboprophylaxis but I do not believe they resolve the complex issue of how to calculate venous thromboembolic risk in medical patients.

As a medical admissions pharmacist I actively assess patients’ thrombotic risk and prescribe the most suitable prophylactic treatment. I will adjust LMWH doses based on renal function and initiate graduated compression stockings as appropriate. Educating medical colleagues and discussing complex patients with them is also important.

Nonetheless, in reflecting on my prescribing of thromboprophylaxis I find inconsistencies. When educating doctors and junior pharmacy staff I tend to encourage aggressive prescribing, meaning most people will receive a LMWH. When considering individual patients I am more reluctant to prescribe.

The difference in approach can be explained by my understanding of the complexities around calculating VTE risk and of the gaps in the literature. For instance, I believe it is unclear whether or not a patient’s thromboembolic risk is cumulative depending on the number of risk factors they possess and, indeed, whether or not all risk factors should carry the same weight.

Despite NICE providing clear recommendations on the matter, I find it difficult to ignore the many unanswered questions, particularly with regard to patients with multiple comorbidities.

There is a dichotomy between what I practise daily and what I teach to colleagues. Is it right that I do not practise what I preach?

David Gibson is senior clinical pharmacist (medical admissions) at Darlington Memorial Hospital

References

1  Samama MM, Cohen AT, Darmon JY, et al. A comparison of enoxaparin with placebo for the prevention of venous thromboembolism in acutely ill medical patients. New England Journal of Medicine 1999:341;793–800.

2  Leizorovicz A, Cohen AT, Turpie AGG, et al. Randomized, placebo-controlled trial of dalteparin for the prevention of venous thromboembolism in acutely ill medical patients. Circulation 2004:110;874–9.