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DOACs safe, effective for A-fib patients with newly diagnosed cancer

ACC 2022
Reuters Health - 11/05/2022 - In patients with atrial fibrillation and newly diagnosed cancer, direct oral anticoagulants (DOACs) are as safe and efficacious as warfarin, according to a poster presentation at the annual American College of Cardiology meeting in Washington, DC.

The researchers analyzed data on 8,420 Medicare patients with incident cancer treated between 2012 and 2016 who were receiving oral anticoagulation for pre-existing atrial fibrillation (52% female, 88% white, average age 78).

At baseline, 5,385 patients were on warfarin and 3,035 were on DOACs. Over the course of the study, warfarin use progressively decreased as DOAC use increased. By 2016, the majority of patients were receiving DOACs, with equal use of rivaroxaban and apixaban and limited use of dabigatran.

There were no significant differences between the warfarin and DOAC groups in rates of previous bleeding or stroke or transient ischemic attack (TIA), but overall, patients on warfarin appeared to be a sicker population. They had higher rates of heart failure (57.1%, versus 49.6% in patients on DOACs), ischemic heart disease (57.1% versus 52.4%), hypertension (86.2% versus 82.6%), diabetes (43.7% versus 372.%), renal disease (33.6% versus 24.8%), use of antiplatelets (5.2% versus 4.4%) and dementia (15.% versus 11.4%).

All comparisons for endpoints were done using propensity scored / overlap weighted groups that were precisely balanced on covariates, according to the research team. Data from the Surveillance Epidemiology and End Results (SEER) program was used in a sensitivity analysis incorporating cancer type and treatment.

Two-year efficacy data showed statistically significant clinical benefits of DOACs for reducing death (HR 0.73, CI 0.74-0.84) and new onset heart failure (HR 0.79, CI 0.63-1.00).

DOACs trended toward superiority over warfarin at the two-year mark for reducing strokes/TIA/embolic events (HR 0.81, CI 0.55-1.16); pulmonary embolus (HR 0.74, CI 0.29-0.84; and deep venous thrombosis (HR 0.52, CI 0.20-1.34). There was no difference in myocardial infarction risk.

Severe bleeding rates at the two year mark were 4.49% with DOACs versus 5.28% with warfarin (HR 0.77, CI 0.53-1.07). Other bleeding rates were similar between the groups.

The curves regarding events began to separate in favor of DOACs within six months; for severe bleeding and death, they began to diverge within three months.

"The overall safety and efficacy of DOACs compared to warfarin were preserved regardless of cancer type, staging, or active treatment with chemotherapy," the researchers wrote in their poster.

Dr. Sean Chen of NYU Langone Health in New York City, who led the study while at the Duke Clinical Research Institute in Durham, North Carolina, told Reuters Health at the conference that the results appeared to align with post-hoc analyses of the initial DOAC studies from ARISTOTLE and ROCKET AF.

The current study, however, was not powered to differentiate the safety or efficacy of the individual DOACs. In a follow-up email, Dr. Chen said, "For the abstract we only looked at patients who were on OAC at the time of diagnosis and afterwards had 'continuous use.'"

SOURCE: https://bit.ly/3M5wxQX ACC.22, April 2, 2022.

By Austin Kutscher MD FACC

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