Validity of {12.34+ (0.69xBMI)} formula for total weekly warfarin dose calculation in antiphospholipid syndrome Jordanian patients

To evaluate the effect of different patient demographic factors on total weekly warfarinmaintenance dose formula {12.34+ (0.69xBMI)} in antiphospholipid syndrome Jordanian patients.Methods: Our prospective observational study included 112 patients, of both sexes, aged 29-64years,classed II-III physical status by the American society of anesthesiologists and presented to therheumatology clinic as antiphospholipid syndrome labeled subjects during the year 2013 at King Husseinhospital, King Hussein medical city, Amman, Jordan, after obtaining approval from our local ethicalboard review committee of the royal medical Jordanian military services. Patients were divided intowarfarin dose group I (n= 56, ≥70mg) and warfarin dose group II (n=56, ≤50mg). Patients with targetINR ranges of 2.5 to 3.5 only were included. Demographic patients data were related to target INR andwith the warfarin weekly maintenance dose {12.34+ (0.69xBMI)} .Results: The mean age was 31.5 years(range of 29-34 years) in group I and 46 years(range of 32-60years) in group II(P<0.05) The female preponderance was 43(76.8%) in group I and 21(37.5%) in groupII.P<0.05. The mean BMI was 38.3kg/m2 (range of 32.2-39.1) in group I and 28.4kg/m2 (range of 25.6-29.5) in group II. Patients presented with target INR were 49 patients (87.5%) in group I and 52 patients(92.9%) in group II. The mean total weekly warfarin dose in group II was 38.1 mg and the mean dose ingroup I was 62.5 mg.Conclusions: Female young Jordanian antiphospholipid syndrome labeled patients need less totalweekly warfarin maintenance dose to achieve INR target of 2.5-3.5 and that the formula cannot be appliedon this group.

Keywords:

anticoagulation , antiphospholipid , demographics , formula , warfarin