Table 1.

Characteristics of included studies

ReferenceCountryNo. of randomized patientsBaseline INRType of VKAVKA indicationTreatment*Follow-up duration, d
Fondevila 200122Argentina109Treatment, 8.4 (6.0-19.6); control, 8.1 (6.0-14.1)ANRIntervention, 1 mg oral vitamin K; comparison: observation7
Crowther 200020Canada92Treatment, 5.4 (4.5-9.8); control, 5.9 (4.5-9.8)WNRIntervention, 1 mg oral vitamin K; comparison: placebo30
Patel 200017United States30Treatment, 7.2 (6.0-9.2); control, 7.0 (6.1-9.5)WVTE, 27%; AF, 44%; CVD, 7%; LVD, 13%; other, 10%Intervention, 2.5 mg oral vitamin K; comparison: placeboNot specified
Ageno 200219Italy, Canada60Treatment, 6.2; control, 6.0AVTE, 32%; AF, 67%; stroke prophylaxis, 1%Intervention, 1 mg oral vitamin K; comparison: observation30
Ageno 200518Italy, United States59Treatment, 7.2; control, 7.7WMechanical heart value, 100%Intervention, 1 mg oral vitamin K; comparison: observation30
Crowther 200921Canada, United States, Italy724Treatment, 6.0 (4.5-9.9); control, 5.8 (4.5-9.5)WThromboembolism treatment or prevention, AF, or artificial heart valveIntervention, 1.25 mg oral vitamin K; comparison: placebo90
  • A, acenocoumarol; AF, atrial fibrillation; CVD, cardiovascular disease; LVD, left ventricular dysfunction; NR, not reported; W, warfarin.

  • * All included studies withheld vitamin K antagonist administration in the treatment and control groups.

  • Study fulfilled the inclusion criteria but reported 0 events and was therefore not included in the meta-analysis.

  • Patients may have more than 1 indication for VKA.