Initiation of warfarin therapy

Abstract

In a prospective, randomized study at two university hospitals, the authors examined how effectively housestaff physicians (n = 36) managed the initiation of warfarin therapy compared with a computer-assisted dosing regimen (n = 39) using the software program Warfcalc, which was managed by one of the authors. Target prothrombin time ratios were selected by the physicians. Study endpoints included: the time to reach a therapeutic prothrombin ratio, the time to reach a stable therapeutic dose, the number of patients transiently overanticoagulated, the number of bleeding complications, and the accuracy of the predicted maintenance dose, which was assessed at steady-state 10-14 days later. Computer-assisted dosing consistently out-performed the physicians: a stable therapeutic dose was achieved 3.7 days earlier (p = 0.002), fewer patients were overanticoagulated (10% versus 41%), and the predicted maintenance dose was in the therapeutic range in 85% of the computer-dosed patients versus 42% of the physician group (p less than 0.002). For physicians who did not routinely manage warfarin therapy, computer-assisted dosing improved the accuracy of dosing and shortened the time required to achieve a stable therapeutic dose.

Computerized clinical decision support systems for therapeutic drug monitoring and dosing: A decision-maker-researcher partnership systematic review

“…Most were used by physicians for decision making, (28/33, 85%) [4-19,21,23,24,26-37], the rest by other health professionals. Recommendations were usually delivered at the time of care (27/31, 87%) [4-7,10-14,16-19,21-26,29-32,34-39] on a desktop or laptop computer (16/25, 64%) [4,10,15,16,18,21,23-26,30-34,39]. Pilot testing was done in 48% (13/27) [6,8,9,16,20,22,24-26,30,33,34,39], training was provided to users in 55% (17/31) [6,7,9,10,12,17,19,20,24,25,27,28,30,31,33-37,39], and the authors were the developers of the CCDSS in 59% (17/29) of studies [5-7,10,11,13,16,19,21,22,26,30-34,39].…”

“…A total of 24,627 patients were included, including one study with 13,219 patients and only six other studies [19,21,26-28,31,34-37] with more than 500 patients. The number of clinics within studies varied from 1 to 66, with the majority being performed at a single centre (63%) [4-9,13-18,21-23,29,30,32,38], and most involved academic centres (73%) [4-7,9,10,12,14,15,18-24,26,29,31,32,34-39]. Financial support was provided by public funding in 16 studies [4,6,8,9,14,19,21,22,24,25,31,32,34-39], private funding in eight studies [8,12,13,16,19,27,28,35-37,39] (four had both), and 13 studies [5,7,10,11,15,17,18,20,23,26,29,30,33] did not report a funding source.…”

“…Overall, 60% of studies (18/30) [4-7,10-13,19,21,24,26,29,30,33,35-39] showed an improvement for process of care, and 21% (4/19) for patient outcomes [10,33,38,39]. It has to be noted that in Cavalcanti et al the CCDSS scored positive on three of four patient outcomes and was therefore positive, but the proportion of patients with hypoglycaemia was actually worse than control [39].…”

“…Vitamin K antagonist (VKA) dosing RCTs (n = 14) [9,10,15,18-20,22-29,35-37] were generally of moderate quality (Table 1). Taking all VKA studies together, process of care was improved in 50% (6/12) [10,19,24,26,29,35-37] of studies with evaluable outcomes, and in meta-analysis the proportion of time in the therapeutic range for the blood International Normalized Ratio (INR) value was improved by CCDSSs (6.14%; 95% CI 0.46 to 11.83 increase; p = 0.03) (Figure 2).…”

“…Taking all VKA studies together, process of care was improved in 50% (6/12) [10,19,24,26,29,35-37] of studies with evaluable outcomes, and in meta-analysis the proportion of time in the therapeutic range for the blood International Normalized Ratio (INR) value was improved by CCDSSs (6.14%; 95% CI 0.46 to 11.83 increase; p = 0.03) (Figure 2). Patient outcomes were improved in 17% (1/6) of studies [10]. …”