Adequacy of anticoagulation in patients with atrial fibrillation: effect of various parameters.

BACKGROUND

Despite reported evidence of the vital importance of appropriate anticoagulation in patients with chronic atrial fibrillation for stroke prevention, this treatment modality still lags behind optimal requirements.

HYPOTHESIS: Our objectives were to evaluate various doctor or patient-related factors that influence quality of control and to assess the adequacy of anticoagulation provided by physicians in the community.

METHODS

In a retrospective study, International Normalized Ratio (INR) values obtained immediately on admission to hospital were considered representative of previous long-term control.

RESULTS

Only 42% of the relevant 385 patient population fell within the protective anticoagulation range of INR 1.91-4.1. The respective figures for patients with poor (INR < 1.5) or suboptimal (INR 1.51-1.9) control, as well as those whose INR values risked bleeding (INR > 4.1), were 28.3, 14.1, and 15.6%. Patient involvement in treatment positively influenced quality of control. By contrast, age 70-80 years or absence of congestive heart failure negatively affected quality of anticoagulation [p = 0.07, odds ratio (OR), 1.7 (95% confidence interval. 0.94-3.08), p = 0.014, OR, 2.06 (95% confidence interval, 1.15-3.7) respectively]. The percentage of patients admitted with stroke who had been adequately anticoagulated was significantly lower than that of patients who had no stroke (21 vs. 44.4%). Adequacy of anticoagulation in patients with cardiac prosthetic valves was superior compared with the rest of the patient population (56.7 vs. 42% with optimal, and only 14.5 vs. 28.3% with poor anticoagulation, respectively), indicating that under the same conditions a better quality of treatment could be achieved.

CONCLUSIONS

Adequacy of anticoagulation in patients with atrial fibrillation lags behind actual recommendations. Better control is required and achievable.