Atrial fibrillation and thromboembolic risk: what is the extent of adherence to guidelines in clinical practice?

BACKGROUND

Atrial fibrillation (AF) is the most common cardiac rhythm disorder in clinical practice, with a growing prevalence in recent decades. Through the use of thromboembolic risk scores it is possible to adjust thromboprophylaxis to individual risk. The aim of this study was to evaluate the conformity of antithrombotic therapy prescribed at hospital discharge with the guidelines in patients with AF and its influence on long-term morbidity and mortality.

METHODS

We performed a retrospective analysis, based on medical records and phone interview, of consecutive patients admitted to an internal medicine department over a one-year period with a diagnosis of AF or atrial flutter--ICD-9-CM 427.31/32. We determined individual thromboembolic risk in accordance with the ACC/AHA/ESC risk categories, and assessed conformity of antithrombotic therapy with the guidelines. Independent predictors of long-term (378 +/- 241 days) mortality and mortality or readmission were identified by multivariate analysis.

RESULTS

The study population consisted of 174 patients with a diagnosis of AF, 59.8% (104) female, mean age 77 +/- 10 years. Hypertension (65.7%) and heart failure (61.3%) were the most prevalent comorbidities. Most patients (82.7%) were stratified as high thromboembolic risk and the remainder as moderate risk. The antithrombotic therapy prescribed at hospital discharge was documented in 155 patients, 126 (81.3%) with high thromboembolic risk. Of the latter group of patients, oral anticoagulation (OAC) was prescribed in 65 (51.6%) and proposed but contraindicated in 24 (19.0%). In patients with moderate thromboembolic risk, therapeutic options were divided between OAC (69.0%), antiplatelet therapy (17.2%) and no thromboprophylaxis (13.8%). Overall there was discordance between the therapy instituted and the guidelines in 25.8% of patients. Age 85 years or over was the only independent predictor of death (HR 1.92; 95% CI 0.94-3.91), while OAC (HR 0.43; 95% CI 0.27-0.70) and male gender (HR 0.58; 95% CI 0.36-0.94) were independent protective factors against death or hospital readmission.

CONCLUSIONS

In this study, patients admitted with AF were mainly elderly, women and with high thromboembolic risk. The prescription rate of OAC in patients at high risk was lower than recommended in the guidelines, which were not followed in a quarter of patients. The main therapeutic option in cases of moderate risk was OAC. OAC use was the only modifiable factor able to improve prognosis of patients with AF, and it is thus crucial to ensure adherence to the guidelines in daily clinical practice.