Improving anticoagulation control in hospitalized elderly patients on warfarin

Abstract

Objectives: To determine the effect of patient characteristics and of specific guidelines that were developed for managing warfarin therapy in older adults and included in an in-house computer program on anticoagulation quality.

Design: Thirteen-month observational study.

Setting: Acute care, extended care, and rehabilitation geriatric wards of a teaching hospital in Paris, France.

Participants: Hospitalized patients (N=307, mean age 86.1 +/- 6.1) treated with warfarin with a therapeutic international normalized ratio range of 2.0 to 3.0.

Intervention: Patients were assigned according to care unit to the computer-generated dosing group (CGD) or the standard management group (SM; usual physician-based care).

Measurements: Relationships between anticoagulation quality criteria and covariates (age, sex, warfarin indication, treatment phase, follow-up duration, model of care).

Results: According to multivariate analysis, only model of care and follow-up duration independently influenced anticoagulation control; the proportion of time within therapeutic INR range 2.0 to 3.0 was significantly greater in the CGD group than in the SM group (59% vs 48%, P=.004). When a wider INR range was analyzed (1.8-3.2), the proportion of time within range was 73% versus 64% (P=.006). Use of the computer was associated with fewer days with INRs greater than 3, a smaller percentage of INRs of 4 or greater, a longer time to the first INR of 4.0 or greater, and a smaller mean number of INRs per month than SM (all P<.01).

Conclusion: Initiation regimen and long-term rules that have specifically been developed and included in a computerized dosage program improve quality of anticoagulation in elderly inpatients, allowing them to benefit from a quality of care as high as that of younger ambulatory patients.