Study: Pharmacist-directed care improves warfarin management

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A pharmacist-directed anticoagulation service improved the transition of care from an inpatient to outpatient setting for patients who received the anticoagulant warfarin, according to a study published in the July/August issue of Journal of Hospital Medicine. The authors suggested that their warfarin management intervention could not only be used by other hospitals to improve transition of care for patients on warfarin but also could be adapted to improve care for patients on other complicated medical regimens.

“The advantage of this service is that it improved the patient transition, enhanced communication between inpatient and outpatient clinicians and ensured that patients made it to their outpatient follow-up appointment after being discharged from the hospital,” the study's senior author James S. Kalus, PharmD, senior clinical pharmacy manager at Henry Ford Hospital in Detroit, said in a statement.

Kalus and colleagues noted that warfarin is implicated in up to 30 percent of reported anticoagulant-related medication errors. Warfarin’s efficacy can be affected by diet and medication interactions, and consequently dosage needs frequent monitoring and adjustments.

Henry Ford designed an inpatient Pharmacist-Directed Anticoagulation Service (PDAS) to improve anticoagulation management. In the study, Kalus et al set out to evaluate the safety and efficacy of the PDAS in the hospital and during the transition after discharge for patients on warfarin.

The researchers conducted a prospective cluster randomized study that included 500 patients from two internal medicine units and two cardiology units who received at least one inpatient dose of warfarin and were scheduled for follow-up at a Henry Ford outpatient anticoagulation clinic after discharge. The patients were assigned to a PDAS group or a control group. The groups were further broken down between patients newly initiated to warfarin and patients continuing an existing warfarin regime.

Transition of care was measured based on four metrics:

  • Appropriate enrollment in the outpatient clinic;
  • Documented communication between the inpatient anticoagulation service and the outpatient anticoagulation clinic;
  • Documented communication between the inpatient anticoagulation service and the physician overseeing the patient’s outpatient anticoagulation management; and
  • The number of patients who complied with an outpatient follow-up within five days of discharge.

Safety and efficacy were determined by evaluating episodes of major bleeding or development of new thrombosis during hospitalization and within 30 days of discharge.

The authors found that overall the PDAS did not affect either the bleeding or thrombotic outcomes, but it did lead to improvements in coordination and documentation of warfarin management and transition of care. In the transition of care metric, 73 percent more of the PDAS group of patients compared to the control group showed compliance.

The researchers conducted a subgroup analysis, which they acknowledged likely were underpowered, for exploratory purposes. “While the safety impact of the PDAS was noted most significantly among the newly initiated patients, the PDAS had a positive effect on the transition of care metrics regardless of previous warfarin use,” Kalus and colleagues wrote.

They pointed out that the study design, while pragmatic, relied on randomly selected units and not individual patients randomized to a service. Nonetheless, they argued that the design was an improvement over previous quasi-experimental designs.

“The PDAS model is a viable approach to standardize anticoagulant management with a goal of improving anticoagulant safety in the inpatient setting … [and] can be an option for improving the transition from the inpatient-to-outpatient setting,” they wrote. “Finally, it may be possible to adapt this model to provide more intensive medication therapy management and monitoring for hospitalized patients with other complicated medication regimes or chronic disease.”