Improving anticoagulation control in hospitalized elderly patients on warfarin

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.

Thirteen-month observational study.

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

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.

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

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

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).

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.