Impact of a pharmacotherapeutic programme on control and safety of long-term anticoagulation treatment: a controlled follow-up study in Spain.

BACKGROUND: In patients undergoing oral anticoagulation treatment, correct control of the international normalized ratio (INR) is necessary. This study sought to assess the effectiveness of a pharmacotherapeutic follow-up programme (PTP) on achieving an optimal INR range, reducing the need for rescue medications and for monitoring the development of possible adverse events associated with poor oral anticoagulation therapy control (haemorrhagic events and thromboembolic disease).
OBJECTIVE: The aim of this study was to evaluate the effectiveness of a PTP targeted at the anticoagulated patient to ensure proper self-control of anticoagulation.
METHODS: This was a prospective, controlled, multicentre cohort study conducted at four primary care centres in Galicia (northwest Spain), covering a group of patients receiving anticoagulation treatment exposed to pharmacotherapeutic follow-up by a primary care pharmacist (n = 272), and a concurrent control group (n = 460). The intervention consisted of a patient health-education programme plus activities involving collaboration with the physician. The educational intervention exposure period was 12 months (starting from February 2006 and finishing in February 2007), during which time a minimum of one INR determination per month was performed. To assess the quality of haematological control, the British Committee for Standards in Haematology criteria were used, namely (i) 50% or more determinations per patient within a range of 0.5 units above or below the target INR; and (ii) 80% or more determinations per patient within a range of 0.75 units above or below the target INR. As an indicator of correct control of coagulation, we also assessed the occurrence of oral anticoagulation therapy-related adverse events, such as active bleeding, haematomas (jointly referred to as haemorrhagic events) and thromboembolic events. Depending on the type of response variable, negative binomial regression or Cox proportional risks models were fitted.
RESULTS: Compared with the control group, the PTP managed to improve correct INR ranges by (i) 25% (relative risk [RR] = 0.75; 95% CI 0.69, 0.82) in terms of the number of patients who had their determinations within ±0.5 units of the target range; and (ii) 26% (RR = 0.74; 95% CI 0.67, 0.81) in terms of the number of patients who had their determinations within ±0.75 units of the target range. Patients belonging to the intervention group registered a 75% reduction in bleeding (hazard ratio [HR] = 0.25; 95% CI 0.18, 0.36). For every 3.27 patients exposed to the PTP, one event would be prevented (number needed to treat = 3.27; 95% CI 2.73, 4.07).
CONCLUSIONS: Including patients receiving oral anticoagulant treatment in a PTP enhances INR control, efficacy and safety of treatment, and efficiency of primary healthcare services.