Patients treated with vitamin K oral anticoagulants in family practice: a new approach to bleeding risk assessment. An ancillary study by the CACAO prospective general practice cohort.

Background: The ability of bleeding risk scores to predict major bleeding (MB) or clinically relevant nonmajor bleeding (CRNMB) remains a topic of contention, particularly in nonselected patients in family practice. In addition, the capacity to predict bleeding risk using simple variables has yet to be established.

Objectives: The main objective was to confirm that severe anemia was the most predictive factor for the estimation of bleeding risk in patients treated with vitamin K antagonists (VKAs). Secondary objectives were to test the capacity of different bleeding scores to detect high-risk patients. Subsequently, the impact of functional decline on bleeding incidence was explored.

Methods: The CACAO study was a multicenter prospective cohort study of patients who, due to nonvalvular atrial fibrillation (NVAF) and/or venous thromboembolism (VTE), had been prescribed an oral anticoagulant by their general practitioner (GP) as a prophylactic measure. Patient characteristics were collected at the time of inclusion by GPs, who then monitored them in accordance with standard practice for one year. MB and CRNMB were the main outcomes for one year. By applying this approach, a total of 13 scores were analyzed.

Results: Aaemia was found to be strongly associated with MB (HR: 2.77, 95% CI: 1.2-6.36), with a particularly pronounced association observed in cases of severe anemia (HR: 12.9, 95% CI: 2.76-60.35). Twelve out of 27 MB cases were not identified by at least half of the scores. By contrast, functional decline was identified as a novel factor associated with MB (HR: 2.45, 95% CI: 1.13-5.31).

Conclusions: Preexisting anemia is a major prognostic factor associated with the occurrence of bleeding. It seems relevant to suggest that functional decline should be considered by GPs when assessing bleeding risk.