LAUSR

In the October issue of Thrombosis andHaemostasis, Geng et al reported treatment satisfaction with dabigatran versus warfarin amongpatientswith atrialfibrillation (AF) in China.1 This time-intensive, patient-centred study with high completion rate of standardized telephone interviews provides high-quality data and key insights from the patients’ perspectives. At 6 months, 33.5% of patients had discontinued dabigatran compared with 19.2% for warfarin. The authors report no difference in the global Anti-Clot Treatment Scale (ACTS) Burdensscoreor theglobalACTSBenefits score. Thefavourable effects of dabigatran regarding decreased concern for dietary or drug interactions and medication-related hassles were offset by the economic burden of dabigatran which is not covered by medical insurance in China. As noted by the authors, the cost of dabigatran is 70 times the cost of warfarin. Factors associated with treatment persistence included older age, longer duration of anticoagulation therapy, global ACTS Benefits score and warfarin therapy. Other important findings of this study include the overall low proportion of patients in the registry receiving anticoagulant therapy, 27%, for stroke prevention. In addition, of the 4,511 patients in the registry receiving an oral anticoagulant, only 18.5% (n 1⁄4 834) were ultimately enrolled in thestudy. Prior topropensityscorematching,warfarin-treated patients were older, had higher CHA2DS2-VASc scores, lower education level and longerdurationofanticoagulationuse. The investigatorsdidnot assess changes inpatient satisfactionover time. Onewould anticipate different attitudes among patients newly starting an anticoagulant opposed to longer term users whose mere persistence is a marker of drug tolerability and patient acceptance. The reasons for medication discontinuation are also of note with 47.6% (dabigatran-treated patients) and 42.9% (warfarin-treated patients) stopping treatment for non-bleeding adverse events, and13.1 and11.4%, respectively, for minor bleeding. Although initiationof anticoagulationamongpatientswith AF remains a major global challenge, treatment persistence is an increasingly recognized major clinical hurdle. Reported rates of treatment persistence vary widely, including within country, depending on the population studied andmethodology used to ascertain treatment exposure. Definitions of gaps in treatment that constitute permanent discontinuation vary across studies. In addition, observational studies restricted to new users of anticoagulant treatment provide different insights and conclusions than those studies composed of switchers, restarts or patients already established on treatment. In a retrospective study conducted in Ontario, Canada, investigators used administrative data to assess treatment discontinuation defined as a gap in dabigatran or rivaroxaban prescriptionsof 14daysor greater.2Thecohortwas comprised of 15,857 dabigatran-treated patients and 10,119 rivaroxaban users. At 6 months, 36.4% of patients had discontinued dabigatran and 31.9% of patients had stopped rivaroxaban. In the United Kingdom, using the primary care Clinical Practice Research Datalink, patients newly starting anticoagulant therapy for incidentAFwere identified (12,307vitamin K antagonist [VKA] and 914 non-VKA oral anticoagulant [NOAC]).3 Treatment persistence at 12 months for VKA was 63.6%and79.2% forNOACs.3 In theDresdenAFRegistry, 124of 341 patients treated with dabigatran discontinued treatment during follow-up (25.8 per 100 patient-years).4 Similar to Geng et al, the main reasons for treatment discontinuation were non-bleeding side effects. Higher rates of treatment persistence were reported from a prospective study of 1,305 patients with AF in Italy. At 12 months, 15.4% of patients stopped NOAC treatment with most of the discontinuations occurring in the first 6 months.5 In the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, 1-year persistence rates for dabigatran were lower than warfarin (adjusted persistence rates: 66% [95% confidence interval [CI], 60–72] vs. 82% [95% CI, 80–84]).6 This is in contrast to a retrospective cohort analysis of a large U.S. commercial insurance database (n 1⁄4 64,661) of patients with AF that found 47.5% of NOAC-treated patients had a proportion of