Thromboprophylaxis in patients with atrial fibrillation: a real practice analysis

Background: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major preventable cause of stroke and hospitalizations, with an estimate prevalence of 2.5%. Current guidelines recommend oral anticoagulant therapy for AF patients at moderate or high risk of stroke. However, despite the effectiveness of oral anticoagulants in stroke prevention, such a therapy remains broadly underused. Purpose: The aim of this study was to evaluate Vitamin K Antagonists (VKAs) treatment in patients with Non Vascular AF (NVAF) in everyday clinical practice in light of current treatment guidelines, and to analyze the costs associated with patient management. Methods: This retrospective observational study was performed utilizing several databases of the Local Health Authority 9 of Treviso, Italy, from January 1, 2010 to December 31, 2013. The cohort of patients affected by NVAF was identified on the basis of Hospital Discharge Records of the years 2010-2013, considering ICD9-CM diagnosis codes for atrial fibrillation and atrial flutter. After the first diagnosis of NVAF, patients have been stratified according to the individual stroke risk (CHA2DS2-VASc score), therapeutic treatment with VKA and achievement of anticoagulation control (Time in Therapeutic Range, TTR). The cost analysis for the year 2013 was performed for naive and prevalent patients, separately; for naive patients, costs in the year 2014 were also evaluated, so that data available for each patient referred to a minimum period of 12 months. Results: The cohort of patients with NVAF identified for the years 2010-2013 comprised 4855 patients, of which 53% were treated with oral VKAs. This percentage decreases to 29.6% considering only patients with at least 6 continuative months of therapy and at least 8 INR (International Normalized Ratio) controls. Furthermore, only 31% of VKA-treated patients reached the therapeutic target (TTR >= 65%). The cost analysis showed that naive patients cost 1.4 times more than prevalent patients. In particular, clinician visits and hospitalizations represent the key cost drivers. On the other hand, costs for anticoagulant and cardiovascular therapies are the lowest expense items, although also in this case they are higher for incident compared to prevalent patients. Conclusions: Management of NVAF patients treated with VKA is challenging, because of the high rate of treatment disaffection and discontinuation. In treated patients, TTR amelioration appears to be a crucial point for effectively preventing thromboembolic risk and reducing rehospitalization costs due to cardiovascular events.