Ablation is the best drug for AF in racial / ethnic minorities
CABANA, which was undertaken to compare catheter ablation and frequency-controlled or rate-controlled drug therapy for AF, concluded that there was no significant difference between the two strategies in improvement. the composite primary endpoint of the trial: death, stroke, severe bleeding or cardiac arrest.
But a closer look at a subgroup of participants reveals a significant difference in outcomes among racial and ethnic minorities.
In this group, which represented approximately 10% of the CABANA study population, catheter ablation was significantly better at treating AF than drug therapy, producing a relative reduction of approximately 70% in endpoint. primary assessment and all-cause mortality.
The benefit of catheter ablation, which was not seen in non-minority participants, appeared to be due to poorer outcomes with drug therapy, investigators report in an article published on July 5 in the Journal of the American College of Cardiology.
“The study really underscores the importance of trying to ensure an inclusive and diverse population in clinical trials,” said lead author Kevin L. Thomas, MD, Duke University Medical Center, Durham, North Carolina. theheart.org | Cardiology Medscape.
“When we focused on the racial and ethnic minorities included in CABANA, the results were different. It was a surprise,” said Thomas.
“The results of CABANA’s secondary analysis suggest that racial and ethnic minorities who are treated with drugs compared to ablation do worse,” he said. “If we could validate this on a larger sample of patients and it actually turns out to be true, then we would change the way we practice medicine. We would discuss with these populations the advantages of ablation over drugs, and this would be important information to guide our practice.
Investigators analyzed data from 1,280 participants enrolled in the North American branch of CABANA. Of these, 127 (9.9%) were from racial or ethnic minorities, as defined by the National Institutes of Health, and were randomized to receive ablation (n = 62) or drug treatment (n = 65).
Compared with non-minorities, racial and ethnic minority participants were younger (median age, 65.5 years, versus 68.5 years) and were more likely to have symptoms of NYHA functional class ≥II (37.0 % vs. 22.0%), hypertension (92.1% vs 76.8%) and an ejection fraction
The overall median follow-up was 54.9 months. Among ethnic and minority participants, the median follow-up was 48 months, compared to 55.5 months for non-minority participants.
Although there was no significant difference in the composite primary endpoint in the CABANA main trial, among racial and ethnic minorities treated with ablation, there was a 68% relative reduction in endpoint. ” primary evaluation of the trial (adjusted risk ratio [aHR], 0.32; 95% CI, 0.13 – 0.78) and a 72% relative reduction in all-cause mortality (aHR, 0.28; 95% CI, 0.10 – 0.79).
The rates of Kaplan-Meier primary events at 4 years were similar in racial / ethnic and non-minority groups who underwent catheter ablation (12.3% vs. 9.9%).
However, the 4-year event rate was much higher among non-minority participants than among racial and ethnic minorities who received drug treatment (27.4% vs. 9.4%).
The 4-year all-cause mortality rates were 8.1% and 6.7%, respectively, in the ablation arm and 20.2% and 4.5%, respectively, in the drug arm.
Thomas and his colleagues point out that heart failure in racial and ethnic minorities, especially black patients, is usually due to hypertensive heart disease, whereas in non-Hispanic white patients, it is predominantly associated with coronary artery disease. “Our results in CABANA therefore raise the possibility that variations in the prevalence of heart disease associated with AF may explain the differences in the benefits seen with ablation therapy.”
Previous data suggests that AF in heart failure with reduced or preserved ejection fraction has significantly better clinical outcomes with ablation compared to drug therapy, but most studies fail to report. racial / ethnic demographics or recruit very few minorities, they note.
Andrea M. Russo, MD, professor of medicine at Rowan University’s Cooper Medical School, Camden, New Jersey, asks why drug therapy could lead to worse outcomes for racial and ethnic minorities in a supportive setting editorial.
“Those who received the ablation did better than those who received the drugs, and the main reason is not that the ablation works better in minorities than in non-minorities, it is because the drugs are worse in minority patients than in non-minority patients. This means that either the way we use the drugs or the ones we use in minority patients cause worse overall results, “said Russo theheart.org | Cardiology Medscape.
“The minority patients were younger and yet had more hypertension to begin with. There could be all kinds of factors contributing to their health,” she said.
Russo agrees with Thomas on the need to enroll diverse populations in clinical trials.
“Dr Thomas is to be congratulated. He did a fabulous job looking into this issue. It’s only 10% of the group, but it’s better than what we’ve had so far, and it’s a start. “said Russo. “This recognizes how important it is to make sure that we include under-represented populations in these trials, and also that we offer all the appropriate therapies to everyone.”
Thomas reports financial relationships with Janssen, Pfizer, Biosense Webster. Russo does not report any relevant financial relationship. The study was funded by the National Institutes of Health, St. Jude Medical Foundation and Corporation, Biosense Webster, Medtronic, and Boston Scientific.