Deborah Layton, Alison Evans, Miranda Davies, Sandeep Dhanda and Saad AW Shakir
Background
The Risk Management Plan for rivaroxaban (Riv) included studies on the utilisation and safety monitoring of Riv prescribed in primary care (a Modified Prescription-Event Monitoring (M-PEM) study; all indications) and secondary care (a Specialist Cohort-Event Monitoring (SCEM) study; selected indications incl. prevention of stroke and systemic embolism in non-valvular atrial fibrillation (AF)).
Objectives
An ad hoc interim analysis to describe the baseline bleeding risk characteristics of two interim study Riv cohorts with AF.
Methods
Both studies used an observational cohort design. Data (incl.selected pt baseline characteristics as per HAS-BLED) were collected from forms sent to specialists in secondary care Sep 2013 to Mar 2015 (datalock) and General Practitioners (GPs) in primary care Dec 2011 to Jul 2015 (datalock). Descriptive statistics & univariate analyses [OR (95%CI)] were calculated (% denominator assumes no missing data). AF cohorts exclude pts with >1 indication.
Results
Interim AF cohort; SCEM=641, 53% male; M-PEM=4764, 52% male. SCEM pts were more likely than M-PEM pts to have a history of stroke [39% vs 14%; OR 3.9 (2.3,4.7)], uncontrolled hypertension [3% vs 1%; OR 3.8 (2.2,6.6)], clinical predisposition to bleeds [4% vs 2%; OR 1.7 (1.1, 2.7); or use drugs predisposing to bleeds [2% vs 1%; OR 3.5 (1.7,6.9)]. Baseline prevalence of abnormal liver function, renal disease, excess alcohol use & age 65+ yrs in the 2 cohorts were similar. The HAS-BLED score distribution differed (ranksum p<0.001); HAS-BLED≥3 [6%vs 2%; OR 3.3 (2.3, 5.0)].
Conclusion
In this ad-hoc analysis, SCEM AF pts appeared to have a higher burden of baseline bleeding risk factors than M-PEM AF pts. This appears to be as expected within healthcare systems, where complex pts with multiple morbidities may be managed by specialists in secondary care. Considerations include differences in the recording of data in medical records held by specialists compared to GPs and interim cohort sample size. Nevertheless, these findings support the need for systematic surveillance across healthcare settings to evaluate full spectrum of pts at risk.