Assessment of patient capability to self-adjust oral anticoagulant dose: amulticenter study on home use of a portable prothrombin time monitor (COAGUCHECK)

Background and Objectives. Self-testing and self-monitoring with portable p rothrombin time (PT) monitors has been shown to be feasible and safe. Howev er the ability of patients an chronic oral anticoagulant therapy (OAT) to s elf-adjust their dose without specific training has never been properly eva luated. The aims of this study were to evaluate: 1) the ability of patients on chronic OAT to self-adjust their dose without specific training; 2) the integration of a portable PT monitor (Coagucheck, Roche Diagnostics, Germa ny) for home use into routine patient care in anticoagulation Design and Methods. A nested case-control study was conducted in four cente rs of the Italian Federation of Anticoagulation Clinics (FCSA). Patients (n =78) on stable OAT for at least 6 months (cases: 47 men, 31 women, age rang e: 18-75 years) were enrolled on a volunteer basis after passing an Abbrevi ated Mental Test and providing informed consent. After three instruction se ssions on the use of Coaguchek, subjects performed the PT test at home, com municated the INR results to the Center and suggested the dose adjustment a nd date for next control as they thought appropriate. However, they were re quested to follow the prescription made by the Center. Controls (78 subject s) matched by age (+/- 5 years), sex and therapeutic range with the cases, were selected from among those who attended the anticoagulation clinics and managed by usual care. Results. When compared with the dose prescribed by the Clinic, the dose sug gested by warfarin and acenocoumarol users was equal to or within +/- 6% of the mean weekly dose in 80% and 82% of suggestions, respectively. Time spe nt in the therapeutic range during the study was the same (80%) for cases a nd controls. Interpretation and Conclusions. Selected patients on chronic anticoagulant therapy can acquire a satisfactory ability for sell-adjustment of OAT dose without specific training. (C)2000, Ferrata Storti Foundation.