Switching frail patients with atrial fibrillation (AFib) from anticoagulation therapy with vitamin K antagonists (VKAs) to a novel oral anticoagulant (NOAC) resulted in more bleeding without any reduction in thromboembolic complications or all-cause mortality, randomized trial results show.
The study, FRAIL-AF, is the first randomized NOAC trial to exclusively include frail older patients, said lead author Linda P.T. Joosten, MD, Julius Center for Health Sciences and Primary Care in Utrecht, the Netherlands, and these unexpected findings provide evidence that goes beyond what is currently available.
“Data from the FRAIL-AF trial showed that switching from a VKA to a NOAC should not be considered without a clear indication in frail older patients with AF[ib], as switching to a NOAC leads to 69% more bleeding,” she concluded, without any benefit on secondary clinical endpoints, including thromboembolic events and all-cause mortality.
“The results turned out different than we expected,” Dr. Joosten said. “The hypothesis of this superiority trial was that switching from VKA therapy to a NOAC would result in less bleeding. However, we observed the opposite. After the interim analysis, the data and safety monitoring board advised to stop inclusion because switching from a VKA to a NOAC was clearly contraindicated with a hazard ratio of 1.69 and a highly significant P value of .001.”
Results of FRAIL-AF were presented at the annual congress of the European Society of Cardiology and published online in the journal Circulation.
Session moderator Renate B. Schnabel, MD, interventional cardiologist with University Heart & Vascular Center Hamburg (Germany), congratulated the researchers on these “astonishing” data.
“The thing I want to emphasize here is that, in the absence of randomized controlled trial data, we should be very cautious in extrapolating data from the landmark trials to populations not enrolled in those, and to rely on observational data only,” Dr. Schnabel told Dr. Joosten. “We need randomized controlled trials that sometimes give astonishing results.”
Frailty a clinical syndrome
Frailty is “a lot more than just aging, multiple comorbidities and polypharmacy,” Dr. Joosten explained. “It’s really a clinical syndrome, with people with a high biological vulnerability, dependency on significant others, and a reduced capacity to resist stressors, all leading to a reduced homeostatic reserve.”
Frailty is common in the community, with a prevalence of about 12%, she noted, “and even more important, AF[ib] in frail older people is very common, with a prevalence of 18%. And “without any doubt, we have to adequately anticoagulate frail AF[ib] patients, as they have a high stroke risk, with an incidence of 12.4% per year,” Dr. Joosten noted, compared with 3.9% per year among nonfrail AFib patients.
NOACs are preferred over VKAs in nonfrail AFib patients, after four major trials, RE-LY with dabigatran, ROCKET-AF with rivaroxaban, ARISTOTLE with apixaban, and ENGAGE-AF with edoxaban, showed that NOAC treatment resulted in less major bleeding while stroke risk was comparable with treatment with warfarin, she noted.
The 2023 European Heart Rhythm Association consensus document on management of arrhythmias in frailty syndrome concludes that the advantages of NOACs relative to VKAs are “likely consistent” in frail and nonfrail AFib patients, but the level of evidence is low.
So it’s unknown if NOACs are preferred over VKAs in frail AFib patients, “and it’s even more questionable whether patients on VKAs should switch to NOAC therapy,” Dr. Joosten said.
This new trial aimed to answer the question of whether switching frail AFib patients currently managed on a VKA to a NOAC would reduce bleeding. FRAIL-AF was a pragmatic, multicenter, open-label, randomized, controlled superiority trial.
Older AFib patients were deemed frail if they were aged 75 years or older and had a score of 3 or more on the validated Groningen Frailty Indicator (GFI). Patients with a glomerular filtration rate of less than 30 mL/min per 1.73 m2 or with valvular AFib were excluded.
Eligible patients were then assigned randomly to switch from their international normalized ratio (INR)–guided VKA treatment with either 1 mg acenocoumarol or 3 mg phenprocoumon, to a NOAC, or to continue VKA treatment. They were followed for 12 months for the primary outcome – major bleeding or clinically relevant nonmajor bleeding complication, whichever came first – accounting for death as a competing risk.
A total of 1,330 patients were randomly assigned between January 2018 and June 2022. Their mean age was 83 years, and they had a median GFI of 4. After randomization, 6 patients in the switch-to-NOAC arm, and 1 in the continue-VKA arm were found to have exclusion criteria, so in the end, 662 patients were switched from a VKA to NOAC, while 661 continued on VKA therapy. The choice of NOAC was made by the treating physician.
Major bleeding was defined as a fatal bleeding; bleeding in a critical area or organ; bleeding leading to transfusion; and/or bleeding leading to a fall in hemoglobin level of 2 g/dL (1.24 mmol/L) or more. Nonmajor bleeding was bleeding not considered major but requiring face-to-face consultation, hospitalization or increased level of care, or medical intervention.
After a prespecified futility analysis planned after 163 primary outcome events, the trial was halted when it was seen that there were 101 primary outcome events in the switch arm compared to 62 in the continue arm, Dr. Joosten said. The difference appeared to be driven by clinically relevant nonmajor bleeding.
Secondary outcomes of thromboembolic events and all-cause mortality were similar between the groups.