Monitoring of patients with anti-coagulation
Evidence from a systematic review has shown that self-monitoring or self-management can improve the quality of oral anticoagulation therapy compared to standard management. The number of thromboembolic events and mortality were decreased without increases in harms. However, self-monitoring or self-management were not feasible for up to half of the patients requiring anticoagulant therapy. Reasons included patient refusal, exclusion by their general practitioner, and inability to complete training.
Recently we have updated this evidence using individual patient data (IPD) which was published by the Lancet at the start of 2012. In this paper, we explored the above findings further, investigating differential effects in pre-specified subgroups or gender, age, indication for treatment and type of intervention.
Control of anticoagulation treatment focuses on the measurement of the international normalized ratio (INR) and adjusting treatment to maintain the INR within specified levels. A systematic review looking at the relationship between different parameters of INR showed that the overall time in therapeutic range (the time within the specified limits) and the percentage of INR readings within range were both accurate measures of INR control.
When patients first start taking warfarin they are given an initial dose of 5mg or 10mg. There is uncertainty which is the best approach to achieve adequate anticoagulation quickly, whilst minimizing the risk of heamorrhage. A systematic review highlighted this uncertainty, but concluded that lower initial doses may be more appropriate in the elderly population.