Deborah Layton, Alison Evans, Miranda Davies, Vicki Osborne and Saad AW Shakir

Background

The Rivaroxaban Observational Safety Evaluation (ROSE) SCEM study is being conducted as part of a risk management plan to monitor short-term (first 3 months) safety and utilisation of rivaroxaban (Riv). A contextual comparator of new user patients (pts) prescribed best practice standard care (warfarin-War) is also being identified. Study objectives include advancing the understanding of the pt population prescribed Riv in the secondary care setting.

Objectives

An interim analysis to evaluate use of HAS-BLED to characterise baseline bleeding risk of pts with AF treated for prevention of stroke/systemic embolism with Riv or War.

Methods

An observational, population-based cohort study. The interim cohort was identified through a specialist network from Sep13 to Mar15 (datalock), supported by UK Clinical Research Networks. Data collected via a questionnaire from consenting pt medical charts by specialists incl. baseline pt characteristics within HAS-BLED. Descriptive statistics & univariate analyses [OR(95%CI)] were calculated (% denominator assumes no missing data).

Results

Interim AF cohort; Riv=641, 53% male; War=477, 56% male. Riv pts were more likely than War pts to have a stroke history [39% vs 26%;OR 1.8(95%1.4,2.3)], but less likely to have renal disease [1% vs 4%;OR 0.2 (95%CI0.1,0.6)] or use drugs predisposing to bleeds [2% vs 5%;OR 0.3 (95% CI0.2,0.7)]. Non-significance differences in baseline prevalence were observed of uncontrolled hypertension (3% vs 4%), abnormal liver function (0.5% vs 1%), predisposition to bleeds (4% vs 4%), excess alcohol use (2% vs 2%) and age 65+ yrs (84% vs 83%), respectively.

Conclusion

This SCEM study shows that HAS-BLED criteria can provide a framework for systematic collection of baseline bleeding risk data. In this interim analysis, some differences were observed between the Riv and War AF cohorts in the reported prevalence of baseline bleeding risk factors. Findings from this interim analysis will become obsolete when all available data are analysed for the final report.