Anticoagulants or blood thinners such as warfarin are medications that prevent blood from clotting. They are usually prescribed to patients who have an increased risk of forming clots, such as after heart valve replacement or in case of atrial fibrillation.

Warfarin is also used in people who have previously developed harmful clots, including patients who have had a stroke, heart attack, a clot which has travelled to the lung (pulmonary embolism), or a blood clot in the leg (deep venous thrombosis or DVT).

What is Atrial Fibrillation?
Atrial Fibrillation (AF) is one of the most common heart rhythm disorders, affecting eight per cent of the population over 80 years of age. Worldwide the impact of AF is enormous, with an estimated 5.6 million people suffer from AF in the US, 4.5 million in Europe and up to eight million in China alone.

AF poses a major public health burden, as the lifetime risk of developing the condition from age 40 years onwards is approximately one in four.

The normal regular resting heart rate for a human is 60 to 100 beats per minute, whereas patients with AF may have either a very low or a very high (up to 175 beats per minute) heart rate. With AF, the two upper chambers (atria) of the heart quiver in a rapid and irregular rhythm (fibrillate) instead of a coordinated contraction.

Only a part of this mechanism's impulse is transferred to the large chambers (ventricles) of the heart, resulting in either an extremely high or extremely low heart beat that could lead to heart failure and death.

Stroke and Atrial Fibrillation
Atrial Fibrillation is considered one of the major risk factors for stroke, as well as a significant contributor to hospitalization of elderly patients, with a 66 percent increase in hospitalization over the last 20 years.

Importantly, stroke and mortality rates for patients with AF are at least twice as high for patients without AF and a stroke caused by AF is much more lethal than other strokes.

How do you treat AF?
Reducing the formation of blood clots is crucial for the prevention of heart attacks, strokes and blockage of major veins and arteries. Anticoagulants such as warfarin have been shown to reduce stroke risks by at least two thirds (68 per cent).

Despite the evidence of the effectiveness of anticoagulants in reducing stroke risk, it is still underused in high risk patients. Worldwide an average of only 30 per cent of patients with AF are treated with oral anticoagulation, whereas it is estimated that 60 to 70 per cent of AF patients should be taking anticoagulants.

There are a number of reasons why the use of anticoagulation therapy is so low, however the most consistent reason is the perceived greater risk of bleeding, an overestimation of the associated risks, underestimation of the stroke risk, and clinical uncertainty or inexperience of warfarin.

A key conclusion of a new consensus paper developed by a multidisciplinary expert group is that when monitored frequently, the benefit of stroke reduction outweighs the risk of bleeding associated with treatment with anticoagulation therapy in high risk patients.

Why is it important to monitor coagulation levels?
The tight monitoring of the intensity of anticoagulation is an important factor for therapy success. Patients taking warfarin are required to measure their prothrombin time (PT), which is an indicator of blood clotting. This is reported as an INR (International Normalized Ratio) level - a unit recommended by the World Health Organization (WHO). An INR of 1 corresponds to normal coagulation; an INR of 2 means that the clotting time is twice as long as normal.

A patient's doctor will change their warfarin dose based on these readings.

Studies have shown the importance of frequent monitoring to maintain the intensity of anticoagulation in a balanced and controlled manner in order to reduce the risk of stroke, as well as to avoid bleeding complications.

The economic impact of Atrial Fibrillation
Atrial Fibrillation represents a considerable healthcare economic burden due to therapeutic interventions associated with increased AF morbidity and mortality.

In the US alone, it is estimated that USD 6.65 billion is spent on the treatment of AF. This includes direct inpatient costs of USD 2.93 billion and outpatient costs of USD 1.53 billion.

It is estimated that if half of all AF patients in routine medical care currently receiving oral anticoagulation were optimally monitored and managed, USD 1.3 billion would have been saved in a year alone.

About CoaguChek®
The CoaguChek® system is a simple, convenient, portable and safe anticoagulation monitoring device, giving on the spot testing results within one minute on a drop of blood. Self-monitoring is straightforward and makes routine testing easier. It returns patients' independence, enhances quality of life and allows them to be directly involved in their own health, collaborating with their healthcare professional.

Regular self-monitoring with CoaguChek® system ensures that the patient manages the right dosage of anticoagulant. More importantly, more frequent testing reduces complications resulting from the underlying disease, lifestyle changes or from the anticoagulant itself.

The author is Chairman and Managing Director of Roche Diagnostics India Pvt. Ltd