12 CHAPTER 1 anticoagulation effective in stroke prevention in patients with AF was a vitamin K antagonist (VKA), such as warfarin, acenocoumarol and phenprocoumon. From 2008 onwards, another oral anticoagulant became available, namely a non-VKA antagonist oral anticoagulant (NOAC), also known as a direct oral anticoagulant (DOAC). There are currently four different NOACs on the market: apixaban, dabigatran, edoxaban, and rivaroxaban. The four pivotal NOAC trials showed that, compared with VKAs, NOACs are at least as effective in preventing ischaemic stroke, but overall have a better safety profile, i.e. a lower risk of severe bleeding, notably intracranial bleeding (relative risk reduction ranging from 29% in patients receiving rivaroxaban to 74% in patients receiving a non-reduced dose of dabigatran).12–15. Therefore, since 2016, guidelines recommend a NOAC in newly diagnosed AF patients instead of VKA treatment, especially when there are no contraindications for a NOAC. Also according to these guidelines, in AF patients already treated with a VKA, switching to NOAC treatment may be considered if time in therapeutic range is not well controlled despite good adherence, or if patients prefer a NOAC and have no contra-indications a NOAC.9 Which NOAC is best is not known, because NOACs have never been compared headto-head to each other in an RCT. FRAILTY AND THE CONSISTENT LACK OF EVIDENCE Frailty involves a lot more than just ageing, multiple comorbidities and polypharmacy. It is a clinical syndrome defined by a high biological vulnerability and a reduced capacity to resist stressors, all leading to reduced homeostatic reserve and to dependency on others.16 In the Netherlands, it is estimated that there are currently 730,000 frail older people (i.e. more than 1 in 25 individuals).17,18 The population of frail elderly grows rapidly as, largely due to improved healthcare, there is a shift in the burden of morbidity from acute to chronic diseases (including AF) and life expectancy increases.17–19 As described above, AF is common, especially in frail older people in whom the prevalence is around 40%.5 The incidence of stroke in frail older patients with AF peaks at 12.3% per year compared to 3.9% per year in non-frail older patients with AF.5 A considerable amount of research has been conducted on AF and its treatment with oral anticoagulation, but important questions remain, especially for the frail elderly population. For example, it is uncertain whether NOACs should be preferred over VKAs in frail older AF patients and it is even more questionable whether frail elderly patients with AF who are stable on VKA treatment should be switched to a NOAC. Observational studies do not provide a proper answer to these questions because they suffer from confounding. And, surprisingly, almost no RCTs have been conducted in frail older people (neither in the field of AF nor in most other clinical fields), which is unjustified given that in this large and increasing population there is the greatest need for evidence and personalised management. Currently, results from
RkJQdWJsaXNoZXIy MTk4NDMw