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Underutilization of anticoagulation therapy in chronic atrial fibrillation
1Department of Internal Medicine, Chang Gung Memorial Hospital, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China.
Insights
Anticoagulation therapy for atrial fibrillation is underused, leading to a high stroke prevalence. Warfarin use and stroke risk varied by atrial fibrillation type, with nonrheumatic valvular disease patients experiencing lower stroke rates.
Area of Science:
- Cardiology
- Vascular Medicine
- Public Health
Background:
- Atrial fibrillation is a common arrhythmia increasing stroke risk.
- Anticoagulation therapy, like warfarin, reduces stroke risk but is often underused.
- Understanding warfarin use and stroke prevalence across different atrial fibrillation etiologies is crucial.
Purpose of the Study:
- To investigate warfarin utilization and stroke prevalence in patients with rheumatic, nonrheumatic valvular, and nonvalvular atrial fibrillation.
- To compare stroke risk and anticoagulation patterns among these patient subgroups.
- To assess the adequacy of anticoagulation monitoring.
Main Methods:
- Retrospective analysis of 457 chronic atrial fibrillation patients from January 1993 to December 1998.
- Categorization into rheumatic heart disease, nonrheumatic valvular disease, and nonvalvular disease groups.
- Evaluation of warfarin use, stroke prevalence, and prothrombin time monitoring frequency.
Main Results:
- Warfarin use was significantly higher in rheumatic heart disease (81.6%) compared to nonrheumatic valvular (16.7%) and nonvalvular (20.1%) atrial fibrillation.
- Stroke prevalence was highest in nonvalvular (40.3%) and rheumatic (33.3%) atrial fibrillation, and lowest in nonrheumatic valvular disease (24.6%).
- Inadequate prothrombin time monitoring was observed in 80% of patients on warfarin.
Conclusions:
- Anticoagulation therapy for chronic atrial fibrillation is significantly underutilized across all valvular disease types.
- Underutilization of anticoagulation likely contributes to the high observed stroke prevalence.
- Patients with nonrheumatic valvular atrial fibrillation had a lower stroke risk compared to nonvalvular atrial fibrillation.
Abstract:
Atrial fibrillation, the most common chronic arrhythmia, results in an increased risk of stroke. Anticoagulation therapy can reduce this risk, but appears to be underused. The objective of this study was to examine the use of warfarin and prevalence of stroke in patients with rheumatic, nonrheumatic valvular and nonvalvular atrial fibrillation. Between January 1993 and December 1998, 457 chronic atrial fibrillation patients with continuous follow-up in our hospital were identified as having rheumatic heart disease (n = 114): nonrheumatic valvular disease (n = 65); or nonvalvular disease (n = 278). Warfarin was used less often in patients with nonrheumatic valvular (16.7%) and nonvalvular diseases (20.1%) than in those with rheumatic heart disease (81.6%, p < 0.001). In contrast, the prevalence of stroke among patients with nonvalvular disease was 40.3% which was similar to the 33.3% found in patients with rheumatic heart disease but significantly higher than the 24.6% found in patients with nonrheumatic valvular disease (p < 0.05). A history of stroke did not alter the trend of use of warfarin among the three groups of patients. Only 20.6% of patients on warfarin received monthly monitoring of prothrombin time. In conclusion, the anticoagulation therapy in our patients with chronic atrial fibrillation, regardless of their associated valvular diseases, is significantly underutilized. This underuse could account for a high prevalence of stroke. This risk of stroke, however, is less in patients with nonrheumatic valvular discase than in those with nonvalvular atrial fibrillation.