AF and diabetes: DOAC better than warfarin for preventing cardiac events


By Mardi Chapman

8 Jul 2019

Rivaroxaban is associated with fewer major adverse cardiac events (MACE) and major adverse limb events (MALE) than warfarin in patients with non-valvular atrial fibrillation and comorbid type 2 diabetes, a study shows.

A retrospective claims analysis in the US of more than 10,000 patients on rivaroxaban and almost 14,000 warfarin users found rivaroxaban was associated with a 25% relative risk reduction of MACE and a 63% relative risk reduction of MALE compared to warfarin.

The rates for MACE were 1.26 per 100 person-years with the DOAC versus 2.07  for warfarin (HR 0.75) while the MALE rates were 0.19 and 0.75 per 100 person-years (OR 0.37) respectively.

Associate Professor William Baker, from the University of Connecticut School of Pharmacy, told the International Society on Thrombosis and Haemostasis (ISTH) Congress in Melbourne that patients had a median age of 70 years, a CHA2DS2-VASc score of 4 and the follow-up period was about 1.4 years.

The study, also published in Diabetes, Obesity and Metabolism, found the two groups of patients had a similar major bleeding risk.

The risk of major limb amputation and endovascular revascularisation separately were also lower with patients treated with rivaroxaban versus warfarin.

Associate Professor Baker said this real world evidence supported and extended the findings of randomised trials.

“There have been prior analyses looking at stroke and systemic embolism in the AF and diabetic cohort but what we hadn’t seen is major cardiac and major limb events.”

Associate Professor Baker said most guidelines recommend DOAC over warfarin for stroke prevention for most patients with AF.

“In terms of what we are seeing in practice, I would say there are still probably one quarter to one third of people receiving warfarin. I think there is still a fair amount of equipoise with clinicians that they are used to warfarin, they are comfortable with warfarin, they like to see that INR number, they know that patients are being controlled.”

“Although I would say the majority now are using DOACs, it’s not anywhere near 100%.”

However the study confirmed there seemed to be more benefits with the DOACs.

Another study presented at ISTH, comprising patients with similar characteristics from the same database and over the same time period, found rivaroxaban was also associated with lower risk of poor renal outcomes than warfarin in patients with AF and diabetes.

The US study found rivaroxaban was associated with a 17% lower risk of acute kidney injury and 18% lower risk of developing stage 5 chronic kidney disease than warfarin.

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