Variations in Quality and Outcomes of Warfarin Therapy in New Zealand
Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
Introduction: Despite the recent introduction of new agents, warfarin remains the most commonly prescribed oral anticoagulant and is used for a variety of cardiovascular and thromboembolic diseases. Warfarin has a narrow therapeutic range. It demonstrates intra- and inter-individual variation in dose response, and is affected by a number of significant interactions. While above range patients are at risk of bleeding, conversely when below range they are not protected against thromboembolic events. The quality of care can be estimated by measuring the proportion of time the patient spends in the therapeutic range (TTR). Aims: To evaluate quality of warfarin treatment in Auckland, New Zealand, using TTR and to find variations of TTR and associations between TTR and clinical outcomes, this to explore possible health inequalities regarding anticoagulation control. Materials and Methods: Patients prescribed warfarin were identified from pharmacy claims data. A number of demographic, laboratory and hospitalisations data were extracted from health databases and linked for analysis. Patient TTRs were calculated using the Rosendaal method. Linear regressions models were developed to find associations between demographics. Cox proportional hazard models were used to evaluate the relationship between TTR and clinical outcomes. Results: The population had a mean TTR of 55.3%. Multivariable regression model showed 4.1% of the variance of TTR to be due to ethnicity, deprivation and age (p<0.05). Increasing TTR indicated less risk of thromboembolic and bleeding events. Conclusions: As expected low quality of treatment is associated with higher risk of adverse events with warfarin. Differences occur between patients in the quality of warfarin. Further research is needed to describe quality of care, and to identify improve patient outcomes.
Place, publisher, year, edition, pages
2015. , 37 p.
Warfarin, anticoagulation, New Zealand, Auckland
Social and Clinical Pharmacy
IdentifiersURN: urn:nbn:se:uu:diva-260679OAI: oai:DiVA.org:uu-260679DiVA: diva2:847972
Subject / course
Master of Science Programme in Pharmacy
Hammarlund-Udenaes, Margareta, Professor