Keep it simple: Forget CHADS scores and prescribe OAC to all older AF patients

Australian GPs could skip the step of calculating stroke risk using CHA2DS2-VA and go straight to recommending anticoagulation therapy in almost all atrial fibrillation (AF) patients from age 65 years, the CSANZ 2022 meeting was told.

The argument to simplify clinical decision making has already been won in Canada where the 2020 Canadian Cardiovascular Society AF guidelines recommend prescription of an oral anticoagulant (OAC) in most patients ≥ 65 years of age.

Speaking at the 70th ASM, Dr Jessica Orchard presented supporting evidence from a large Australian dataset of more than 340,000 patients from 164 general practices.

She compared GP recommendations for anticoagulation therapy in 8,300 AF patients when assessed using the older CHADS2 score versus the current CHA₂DS₂-VA as per the 2018 Australian NHF/CSANZ AF guidelines.

Dr Orchard, a postdoctoral research fellow at the University of Sydney, said amongst the adult AF patients of all ages, the CHA₂DS₂-VA threshold captured a significantly higher proportion of patients than the CHADS2 threshold (85% v 65%).

“Similarly among AF patients aged just in the 65+ age group, the CHA₂DS₂-VA also captured a significantly higher proportion than CHADS2 at 96% versus 76%.”

She said when broken down further, the proportion of 65-74 years olds captured by CHA₂DS₂-VA or CHADS2 were 87 v 36% respectively and there was a much smaller difference in >75 year olds of 100% v 95%.

“So the vast majority of older patients over 65 years who are captured by the CHA₂DS₂-VA but not the CHADS2, qualified on the basis of age alone,” she said.

There was almost no difference in the <65 year olds who qualified for anticoagulants using either score (both 29%).

“Our results do show what you might expect – that a significantly higher proportion of AF patients are now recommended OAC treatment using the  threshold versus the older CHADS2 score with this difference driven almost entirely by the revised scoring for age.”

“Our findings also reinforce the argument that the AF screening in age 65 years and up is justified because almost all the new cases identified are likely to be eligible for treatment. It’s almost everyone.”

Dr Orchard said OAC treatment rates in AF have improved in Australia to about 70-80% but there are still some important gaps.

“Our results also suggest there could be an argument for simplifying the treatment message for GPs because this might further reduce barriers to treatment and improve treatment rates.”

She said given that almost all AF patients ≥65 years qualified for OAC, there probably should be a switch in thinking from identifying patients in whom OAC treatment was indicated to identifying patients with reversible causes of increased bleeding risk.

“If you get to the point where 96% of your patients aged ≥65 years are qualifying under the guidelines, then really it’s only a couple who are not.”

“It may be that the Australian guidelines get updated at some point, but I do think that communication for GPs on this point needs to be made simple and possibly needs to empower them to make those decisions perhaps before the patient is able to see a cardiologist.”

The meeting heard that PBS criteria for OAC therapy in AF patients is still based on the old CHADS2 score.

“It’s not really fair to put people in the position of having an inconsistency in the guidelines versus the PBS so that’s probably a simple one to sort out,” Dr Orchard said.

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