A randomized controlled trial of shared care versus routine care for patients receiving oral anticoagulant therapy


Tomas Holm, The Unit of Health Technology Assessment, Aarhus University Hospital, Olof Palmes Allé 17, 1, DK-8200 Aarhus N, Denmark (fax: +45 8739 75 77; e-mail: tom@ag.aaa.dk).


Objectives.  To evaluate the effect of a shared careprogramme (SCP), defined as a scheme based on shared responsibility, enhanced information exchange, continues medical education and explicit clinical guidelines, between general practitioners (GPs) and a hospital outpatient clinic (HOC), on oral anticoagulant therapy (OAT).

Design.  The study was a 2-year prospective, randomized, controlled trial, preceded by a 1-year period of observation.

Setting.  The HOC, GPs, and OAT patients in the admission area of Aarhus University Hospital, Aarhus County, Denmark, covering 310 300 inhabitants.

Subjects.  A total of 207 GPs, including their enlisted patients on OAT, were invited, and 61.4% accepted participation. They were randomized into an intervention group [group-INT: 64 GPs and 453 patients (170 patients on OAT throughout the study period, i.e. full follow-up)], and a control group [group-CON: 63 GPs and 422 patients (173 with full follow-up)]. The remaining 80 GPs served as a nonresponder group (group-NON) of 485 patients (184 with full follow-up).

Main outcome measure.  Therapeutic control of OAT in terms of time spent by the patients within the therapeutic interval (TI) of an international normalized ratio (INR) between 2.0 and 3.5.

Results.  The groups did not differ significantly with regard to age, sex, OAT indication, anticoagulant drug used, or the therapeutic control at baseline. In a comparison based on intention-to-treat principles, the therapeutic control increased statistical significance amongst patients with full follow-up in group-INT compared with group-CON (median time within TI: group INT = 86.6% vs. 80.5%, P = 0.007).

Conclusion.  An SCP of anticoagulant management is effective in reducing patient time outside the therapeutic INR interval in OAT patients randomly assigned to an SCP, as compared with a control group.