Economic evaluation of a randomized controlled trial of pharmacist-supervized patient self-testing of warfarin therapy

Abstract

What is known and objective: The increase in numbers of patients requiring oral anti-coagulation testing in outpatient clinics has focused attention on alternative flexible systems of anti-coagulation management. One option is pharmacist led patient self-testing (PST) of international normalised ratio (INR) levels. PST has demonstrated improvements in anti-coagulation control, but its cost-effectiveness is inconclusive. This study reports the first cost-effectiveness evaluation of a randomized controlled trial of an automated direct-to-patient expert system, enabling remote and effective management of patients on oral anti-coagulation therapy.

Methods: We conducted an economic evaluation alongside a randomised controlled trial investigating a pharmacist led PST method. The primary outcome was to determine the cost effectiveness of PST in comparison with usual care (management in a hospital based anti-coagulation clinic). Long term anti-coagulation patients were recruited to a 6 month cross over study between PST and routine care in an anti-coagulation clinic. Economic evaluation was from the healthcare payer perspective.

Results and discussion: On a per patient basis over a 6 month period, PST resulted in an incremental cost of €59.08 in comparison with routine care. Patients achieved a significantly higher time in therapeutic range (TTR) during the PST arm in comparison with routine care, (72 ± 19.7% vs. 59 ± 13.5%). Overall cost of managing a patient through pharmacist supervised PST for a 6 month period is €226.45. Additional analysis of strategies from a societal perspective indicated that PST was the dominant strategy.

What is new and conclusion: Pharmacist led patient self-testing is a viable method of management. It provides significant increases in anti-coagulation control for a minimal increase in cost.

Keywords: anti-coagulation; clinical pharmacy; cost-effectiveness; international normalised ratio; pharmaceutical care; pharmacoeconomics; pharmacy practice; warfarin.