Optimal measures of oral anticoagulation in atrial fibrillation: a systematic review

AIM: To evaluate different measures of oral anticoagulation in patients with atrial fibrillation (AF) and to compare the application of different measures in clinical practice. METHODS: Evidence-based method was used to search MEDLINE, EMBASE and Cochrane Library (1998 to 2008) for studies (with adjusted dosage warfarin therapy) reporting international normalized ratio (INR) control measures as percentage of time in range (TTR), percentage of INRs in range, and percentage of patients in range and other same measures. RESULTS: Fifty publications with 68 study groups were identified. The sample size of studies was from 25 to 6 454 (mean 757). Duration or follow-up of studies was from 3-42 months (median: 12 months). TTR (69%) and percentage of INRs in range (37%) were the most popular measures. Only 9% of the total studies used both measures at the same time. A significant difference was found between the two measures ［(59±13)% vs.(53±10)%, P=0.002］, and a significant correlation was also found (r=0.988, P<0.001). CONCLUSION: TTR and percentage of INRs in range are the most popular measures used in anticoagulation control.