Patients With A-fib and Cancer May Benefit From Visiting With a Cardiologist Early On

Among patients with A-fib, those who have a history of cancer are less likely to see a cardiologist, a study of claims data suggests. But those with a malignancy who do visit a specialist are likely to take away something positive from the encounter.

Patients with both A-fib and cancer who were seen by a cardiologist were more likely to fill prescriptions for oral anticoagulation (RR 1.48; 95% CI 1.45-1.52) and—during a mean follow-up of about a year—had a lower risk of stroke (HR 0.89; 95% CI 0.81-0.99) without an increased risk of bleeding (HR 1.04; 95% CI 0.95-1.13), researchers led by Wesley O’Neal, MD (Emory University, Atlanta, GA), report in a study published online ahead of the October 16, 2018, issue of the Journal of the American College of Cardiology.

“We’re dealing with an aging population. Cancer therapies are getting better. We’re going to see more survivors of cancer, and by definition and just how the epidemiology works out, they’re going to be older and they’re going to have cardiovascular conditions,” O’Neal told TCTMD, adding that A-fib is frequently seen in patients with a history of cancer.

“Regarding how to move forward and how to best treat these patients, I think you’re seeing a lot of large centers have already moved toward . . . a multispecialty approach when dealing with patients who have oncologic issues,” he said. “Cardio-oncology is kind of an emerging field still in its infancy where patients may see an oncologist in the morning and a cardiology provider in the afternoon to further tailor their care.”

And that collaborative approach is particularly important, O’Neal said, because “a lot of these therapies that we prescribe really have to be decided on the individual patient level.”

Prior studies have shown that patients with a history of cancer—either active or in the past—who present with cardiovascular disease are less likely to receive guideline-directed therapies. O’Neal and colleagues wanted to explore how patients with cancer and A-fib are managed and whether they are seeing cardiologists early on. Early cardiology care has been linked to better outcomes in the general A-fib population, both in the United States and Canada.

To take a closer look at the subset of patients with A-fib who have a history of cancer, the investigators turned to Truven Health MarketScan databases containing commercial and Medicare claims from 2009 to 2014. The analysis included 388,045 patients with A-fib (mean age 68; 59% men), 17% of whom had either active or prior cancer. The most common cancer diagnoses involved the prostate and breast.

Patients with a history of malignancy were less likely to visit with a cardiologist in the period around their A-fib diagnosis (54% vs 62%; RR 0.92; 95% CI 0.91-0.93) or to fill prescriptions for anticoagulants (31% vs 35%; RR 0.89; 95% CI 0.88-0.90), which, the authors say, could be “due to negative perception of survival or a lack of perceived benefit with anticoagulant agents.”

Those who did see a cardiologist seemed to derive some benefit in terms of increased use of oral anticoagulation and a lower stroke risk. “I think overall this makes a nice point that . . . seeing a cardiology provider is beneficial in this patient population, and we really need dive in further to understand the intrinsic differences in why some of these patients make it to a cardiology provider and why some do not,” O’Neal said.

On the flip side, however, visiting with a cardiologist was also associated with greater risks of being hospitalized for heart failure (HR 1.30; 95% CI 1.20-1.41) and for A-fib (HR 1.44; 95% CI 1.34-1.55).

To explain that, O’Neal said cardiologists are likely to see patients with more severe disease and to treat cardiovascular disease more aggressively than primary care physicians, a point supported by greater use of antiarrhythmic and heart failure therapies in patients who received cardiology care. “I don’t think that’s anything to worry about per se,” he said.

Interdisciplinary Approach Needed

In an accompanying editorial, Sean Chen, MD, and Chiara Melloni, MD (Duke University, Durham, NC), point out that managing patients with A-fib and cancer can be challenging because of “unpredictable changes in thrombosis and bleeding risk” and difficulties in using warfarin because of drug interactions and varying nutritional status. There is also limited experience in using direct oral anticoagulants in this setting.

When interpreting the potential clinical implications of the study by O’Neal et al, they say, there are some issues to consider due to the observational design of the analysis, particularly regarding the mechanisms linking cardiology care to better outcomes.

“Nevertheless, the investigators should be commended on an insightful and thought-provoking analysis. This is one of the first studies identifying the suboptimal use of anticoagulation therapy in this population,” Chen and Melloni write. “Furthermore, the results of the study make a compelling argument that early cardiology involvement is associated with lower rates of stroke without higher bleeding risk, even in those with actively treated cancer.”

Though not every patient newly diagnosed with A-fib needs to be referred to a cardiologist, “high-risk cancer patients would likely benefit from initial cardiology consultation for diagnostic assessment and consideration of different therapeutic options,” they say.

Ultimately, “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,” Chen and Melloni conclude. “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.”

Because atrial fibrillation is an important comorbidity in patients with cancer, they write, “future recognition and appropriate management of AF in this setting will be crucial in reducing morbidity and mortality in this vulnerable population.”