A meta-analysis published Online First in The Lancet shows that patients who self-monitor their blood-thinning (oral anticoagulation) therapy with vitamin K antagonists (VKA), such as warfarin, almost halve their risk of developing thromboembolic events like stroke, deep vein thrombosis and heart attack compared with those who receive traditional care.
About 1 million people in the UK are eligible for oral anticoagulation therapy, and in Europe over 4 million patients are taking long-term oral anticoagulation for conditions, such as cardiac arrhythmias, artificial heart valves, or with a previous history of blood clots. As the population is ageing, the demand for oral anticoagulants is predicted to increase dramatically.
Each patient responds differently to the same VKA dose. Because the therapeutic range for VKA is limited, it is necessary to regularly monitor the patient's blood and, if necessary, adjust the dose to prevent excessive anticoagulation that can lead to major bleeding, or inadequate anticoagulation that can result in patients developing potentially fatal blood clots that these drugs are supposed to prevent.
It is more convenient for patients to self-monitor as it can improve the quality of anticoagulation, yet self-testing in which patients test themselves with dosage adjustment carried out by a doctor, as well as self-management, when they test themselves and also adjust their own dosage, remains inconsistent both in and between countries, ranging from just 1% of patients in the USA to 20% of patients on anticoagulant therapy in Germany.
Study leader Carl Heneghan, from the University of Oxford, UK, wanted to provide more evidence on the benefits of self-monitoring. They combined individual patient data from 11 randomized trials, which compared self-monitoring of oral anticoagulation with conventional care.
Heneghan and his team estimated the effect of self-monitoring on first major bleeding event, first thromboembolic event and time to death in important patient subgroups, such as the elderly and those with atrial fibrillation, a common and significant risk factor for stroke, and those with a mechanical heart valve.
They discovered that overall, self-monitoring decreased the risk of thromboembolic events by 49% compared with traditional care but discovered that the rate of bleeding complications was comparable in both groups. They also established that self-monitoring had no major effect on mortality.
They noticed that the benefits of self-monitoring were considerable in those below the age of 55 years, who had a lower than 60% chance of having a thromboembolic event, and in patients with a mechanical heart valve, whose risk was halved.
Significantly, they noted that self-monitoring decreased mortality and did not raise complications in old patients, who are at high risk of major bleeding, which indicates that age should not be used as a factor to determine whether a person if eligibility to self-manage.
In a concluding statement the authors say:
"Self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages. Patients should also be offered the option to self-manage their disease with suitable health-care support as back-up."
Paul Alexander Kyrle and Sabine Eichinger from the Medical University of Vienna in Vienna, Austria, state in a linked comment:
"Self-management (rather than self-testing) of treatment with vitamin K antagonists should be offered to patients with mechanical heart valves, especially to those younger than 55 years. However, we do not see a place for self-monitoring in other areas of this treatment except for individual patients for whom access to routine usual anticoagulation care is restricted."
Written by Petra Rattue