AF in ethnic/racial minorities

Hypertension, diabetes, and heart failure - all have a higher prevalence in the black and Asian minority ethnic (BAME) communities in the West and all three are strong risk factors for atrial fibrillation.

However, it is a paradox that BAME communities have this higher risk profile for atrial fibrillation but a lower actual incidence of atrial fibrillation. It's easier to think of white communities as having a higher incidence as studies in Europe and America have demonstrated this racial difference. In contrast, no strong patterns emerge when comparing different BAME groups. The prevalence amongst non-Hispanic white/European descent white communities is 3-5% whereas it is 1-2% amongst BAME groups. Objectively, this should be the other way round- like it is for coronary disease and heart attacks.

It is important to objectively study these differences because the insights may have benefit for everyone. If a genetic cause, behavioural difference or biological difference can be identified, this may be a potential target for AF treatments and improve our understanding of this condition.

As we've come to understand with AF, it's rarely just one thing- studies have found higher markers of inflammation (a potential driver of heart scarring that can drive AF) and higher prevalence of ectopics (extra heartbeats that may precede AF). But neither of these findings satisfactorily explains why racial differences exist.  There are also reported differences in experiences and behaviours- American registries report BAME patients have worse AF symptoms and are more likely to be managed with rate control medications.

A genetic explanation would make sense. European ancestry is a risk factor for incident AF and perhaps an accountable gene that increases AF risk is more commonly expressed through European ancestry. This may well be the case but as we said in our discussion of AF and genetics, we don't fully understand the genetic basis of this condition yet and so there may be a genetic association that we haven't identified yet. Studies of the genes we know about so far have been inconclusive.

A lot of the answers here are unknown. Things become more complicated if we think there may be differences in how well we are identifying AF in BAME populations? Perhaps they engage less with healthcare providers, or perhaps are less likely to report symptoms and have them investigated, so the BAME individuals who are actually diagnosed and included in these registries are the highly symptomatic patients who presented because they were debilitated. This can be a confusing point but it's about the "unknowns unknowns". How much AF is out there in the BAME community that we just aren't capturing?

But whatever the explanation, the low prevalence leads to under-representation in AF studies and then we have to try to infer how much we can extrapolate across different racial groups- can we quote the same AF ablation success rates? complication rates? what about medication choices? I think the ongoing genome-wide association studies are promising and may identify a reason for the link between European ancestry and AF but the challenge of how we act on that will then be for patients, physicians and regulators to interpret.

If you want to read further, here's a very nice review of all the different aspects of racial/ethnic differences in AF and patient care: Ugowe, Francis E.; Jackson, Larry R.; Thomas, Kevin L. (2018). Racial and ethnic differences in the prevalence, management, and outcomes in patients with atrial fibrillation: A systematic review. Heart Rhythm, (), S154752711830506X–. doi:10.1016/j.hrthm.2018.05.019