Adequacy of anticoagulation in patients with atrial fibrillation: Effect of various parameters

Background: Despite reported evidence of the vital importance of appropriat e anticoagulation in patients with chronic atrial fibrillation for stroke p revention, this treatment modality still lags behind optimal requirements. Hypothesis: Our objectives were to evaluate various doctor-or patient-relat ed 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) val ues obtained immediately on admission to hospital were considered represent ative of previous long-term control. Results: Only 42% of the relevant 385 patient population fell within the pr otective 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 wel l as those whose INR values risked bleeding (INR > 4.1), were 28.3, 14.1, a nd 15.6%. Patient involvement in treatment positively influenced quality of control. By contrast, age 70-80 years or absence of congestive heart failu re 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% confi dence interval, 1.15-3.7) respectively]. The percentage of patients admitte d with stroke who had been adequately anticoagulated was significantly lowe r than that of patients who had no stroke (21 vs. 44.4%). Adequacy of antic oagulation in patients with cardiac prosthetic valves was superior compared with the rest of the patient population (56.7 vs. 42% with optimal, and on ly 14.5 vs. 28.3% with poor anticoagulation, respectively), indicating that under the same conditions a better quality of treatment could be achieved.