Collaborative home medicines review delays time to next hospitalization for warfarin associated bleeding in Australian war veterans

Abstract

What is known and background: Unintended bleeds are a common complication of warfarin therapy. We aimed to determine the impact of general practitioner–pharmacist collaborative medication reviews in the practice setting on hospitalization-associated bleeds in patients on warfarin. Method: We undertook a retrospective cohort study using administrative claims data for the ambulatory veteran and war widow population, Australia. Participants were veterans, war widows and their dependents aged 65 years and over dispensed warfarin. The exposed groups were those exposed to a general practitioner (GP)–pharmacist collaborative home medication review. The service includes GP referral, a home visit by an accredited pharmacist to identify medication-related problems, a pharmacist report with follow-up undertaken by the GP. The outcome measure was time to next hospitalization for bleeding. Results: There were 816 veterans exposed to a home medicines review and 16 320 unexposed patients, with an average age of 81·5 years, and six to seven co-morbidities. Adjusted results showed a 79% reduction in likelihood of hospitalization for bleeding between 2 and 6 months (HR, 0·21 95% CI, 0·05–0·87) amongst those who had received a home medicines reviewed compared to the unexposed patients. No effect was seen in the time period from review to 2 months, nor in the time period 6 to 12 months post a review. What is new and conclusion: Medicines review in the practice setting delays time to next hospitalization for bleeding in those treated with warfarin in the period 2 to 6 months after the review, but is not sustained over time. Six monthly medication reviews may be required for patients on warfarin who are considered at high risk of bleeding.