Optimizing quality care for the oral vitamin K antagonists (VKAs)

Vitamin K antagonists (VKAs) have been the only oral anticoagulants for decades. The management of anticoagulant therapy with VKA is challenging because of the intricate pharmacological properties of these agents. The success of VKA therapy depends on the quality of treatment that is ensured through continuing comprehensive communication and education. The educational program should address important issues of the VKA therapy such as beginning of treatment, pharmacological, dietary, and drug-drug interactions, as well as treatment temporary suspension during surgical interventions or invasive maneuvers. In addition, the initial and continuing patient education is of imperative importance. A major role in the educational process may be addressed by patient associations. The quality of treatment is better reached if patients are followed in anticoagulation clinics. Moreover, a federation of anticoagulation clinics may improve patient care through regular meetings to update knowledge on VKA treatment. Learning objectives of this paper is to allow readers to correctly approach patients starting VKA treatment, recognize possible pitfalls of treatment, and provide adequate solutions.

Vitamin K antagonist use in the elderly: special considerations

As the population ages, the number of patients aged 75 years and over treated with vitamin K antagonists (VKAs) is steadily increasing. In this age group, the two main indications for oral anticoagulant therapy are the treatment of venous thromboembolic disease and the prevention of systemic embolism in patients with nonvalvular atrial fibrillation. In both indications, a target international normalized ratio of 2.5 (range: 2.0-3.0) is recommended. Although VKAs are beneficial in thromboembolic disorders, they are still underused. In this review, we will focus on two crucial topics in elderly patients, the specific management of VKAs in these patients and the hemorrhagic risk. Current recommendations concerning the management at the start of treatment, education and adequate monitoring may help to minimize the hemorrhagic risk in these frail patients.

The risks of warfarin use in the elderly

The use of warfarin in the elderly, particularly for stroke prevention in chronic atrial fibrillation, is steadily increasing. Although the benefits of warfarin are greatest in the elderly, so are the risk of adverse outcomes and the difficulties of anticoagulant management. Clinical systems need to improve to counter this therapeutic dilemma, as warfarin is likely to remain the only widely available oral anticoagulant for the foreseeable future. Aspects that require attention are: the careful selection of patients in whom treatment with warfarin is appropriate; initiating therapy in a low dose (e.g., 2.5-5 mg/day); thorough education of patients and carers; close monitoring, especially with any change in the patient's regular drug therapy; involving patients more in the management of their warfarin therapy (self-monitoring/management in suitable patients); and ongoing review of the appropriateness of therapy as circumstances change.

Improving the outcomes of anticoagulation: an evaluation of home follow-up of warfarin initiation

OBJECTIVES

A number of studies have reported that the risk of bleeding associated with warfarin is highest early in the course of therapy. This study examined the effect of a programme focused on the transition of newly anticoagulated patients from hospital to the community.

DESIGN

Open-label randomized controlled trial.

SETTING

Home-based follow-up of patients discharged from acute care hospital in southern Tasmania, Australia.

SUBJECTS

A total of 128 patients initiated on warfarin in hospital and subsequently discharged to general practitioner (GP) care were enrolled in the study. Sixty were randomized to home monitoring (HM) and 68 received usual care (UC).

INTERVENTIONS

HM patients received a home-visit by the project pharmacist and point-of-care international normalized ratio (INR) testing on alternate days on 4 occasions, with the initial visit two days after discharge. The UC group was solely managed by the GP and only received a visit 8 days after discharge to determine anticoagulant control.

RESULTS

At discharge, 42% of the HM group and 45% of the UC group had a therapeutic INR. At day 8, 67% of the HM patients had a therapeutic INR, compared with 42% of UC patients (P < 0.002). In addition, 26% of UC patients had a high INR, compared with only 4% of HM patients. Bleeding events were assessed 3 months after discharge and occurred in 15% of HM patients, compared with 36% of the UC group (P < 0.01).

CONCLUSIONS

This programme improved the initiation of warfarin therapy and resulted in a significant decrease in haemorrhagic complications in the first 3 months of therapy.