When cardiologists get involved in the treatment of patients with a history of cancer and newly diagnosed atrial fibrillation (AFib), those people see a subsequent 11 percent reduction in the risk of stroke, according to a new study in the Journal of the American College of Cardiology. But the same analysis revealed cardiologist involvement and anticoagulant treatment occurs significantly less often in that subgroup of patients than in AFib patients without cancer.
“It is possible that patients with AF and history of cancer are less likely to receive antithrombotic therapies or see cardiology providers after their diagnosis due to negative perception of survival or a lack of perceived benefit with anticoagulant agents,” wrote lead author Wesley T. O’Neal, MD, MPH, with Emory University School of Medicine in Atlanta, and colleagues. “This is supported by recent data demonstrating that patients with a history of cancer are less likely to receive guideline-recommended treatment for coronary heart disease events.”
O’Neal and coauthors used the Truven Health MarketScan database from 2009 to 2014 to identify 64,016 patients with AFib who had a history of cancer.
Compared to more than 300,000 AFib patients from the same database without cancer, those with a history of malignancy were 8 percent less likely to be seen by a cardiologist (54 percent versus 62 percent) within six months of their AFib diagnosis. They were also 11 percent less likely to fill prescriptions for anticoagulants during that time period.
However, cancer patients who were seen by cardiologists were 48 percent more likely to get anticoagulants than those who weren’t. In addition, they demonstrated an 11 percent reduction in stroke risk during an average follow-up of 1.1 years, without a significant difference in bleeding events (hazard ratio: 1.04).
“Patients with AF and a history of cancer often receive suboptimal anticoagulation for stroke prevention, but early involvement of a cardiologist is associated with more frequent filling of oral anticoagulant prescriptions and improved clinical outcomes,” O’Neal et al. wrote. “Further studies are needed to determine optimal management strategies for patients with AF and a history of cancer, including those that encourage early inclusion of a cardiologist on the care team.”
In a related editorial, two researchers from Duke University Medical Center noted cardiologists’ abilities to lower stroke rates in this population “likely extend well beyond rates of anticoagulation use.”
“Differences in the use of rhythm control strategies with catheter ablation or direct current cardioversion are important mediators to recognize,” wrote Sean T. Chen, MD, and Chiara Melloni, MD, MHS. “Optimization of cardiovascular comorbidities, such as hypertension, hyperlipidemia, or coronary artery disease, may also affect stroke risk.”
Notably, the study results were similar when stratified by whether patients had an active or remote history of cancer.
Another important finding was that cancer patients seen by a cardiology provider were more likely to experience hospitalizations for heart failure or AFib, which the researchers attributed to a greater burden of baseline comorbidities as well as more aggressive cardiovascular treatment following visits with cardiologists. Indeed, patients with a history of cancer who were seen by cardiologists within six months of AFib diagnoses were 65 percent more likely to receive rhythm control therapies.
O’Neal and colleagues said the efficacy of certain anticoagulants remains unknown in this population because cancer patients are often excluded in clinical trials. Even so, their results indicate a cardiologist’s judgment could improve outcomes.
“Although the decision to initiate antithrombotic therapy or refer to a cardiology provider in AF patients with cancer history should be individualized based on patient characteristics, such as life expectancy and bleeding risk, the data in this report suggest that cardiology providers positively influence outcomes among AF patients with a history of cancer, and this is not limited to patients with a remote history of cancer,” they wrote.
Chen and Melloni noted this is an important area of study, as the number of cancer survivors in the U.S. currently exceeds 15 million people and is expected to increase to more than 20 million by 2026.
“The management of cancer patients must extend beyond their primary malignancy and will require an interdisciplinary approach from oncologists, primary care providers, and other subspecialists,” the editorialists wrote. “The increase in survivorship is a testament to the dramatic improvements in cancer therapy, but continued emphasis on a patient’s diagnosis of cancer can shift significant attention away from other essential aspects of care.”