Post-MI heart failure increases cancer risk
medwireNews: Myocardial infarction (MI) survivors who have heart failure are more likely to develop cancer than their heart failure-free counterparts, indicates research published in the Journal of the American College of Cardiology.
“This finding extends our previous report of an elevated cancer risk after [heart failure] compared with [community] controls, and calls for a better understanding of shared risk factors and underlying mechanisms”, say the researchers.
They add that “[i]n the meantime, physicians taking care of [heart failure] patients should be aware of the increased risk of cancer and endorse the current guidelines for proper cancer surveillance for early detection.”
Writing in an accompanying editorial, Jyoti Malhotra (Rutgers Cancer Institute of New Jersey, New Brunswick, USA) and Paolo Boffetta (Icahn School of Medicine at Mount Sinai, New York, USA) say that the study raises interesting questions about the underlying mechanisms. But they believe that “[m]ore definite evidence is needed before recommendations for cancer prevention in this patient group can be developed.”
Of 1081 residents of Olmsted County in Minnesota, USA, without a history of heart failure or cancer who had an MI between 2002 and 2010, 228 subsequently developed heart failure with a median time to diagnosis of 3 days. And 12.3% of these individuals went on to receive a cancer diagnosis within a median of 2.8 years, compared with 8.2% of the 853 who remained heart failure-free after the MI.
The incidence of any cancer (except nonmelanoma skin cancer) was 33.7 per 1000 person–years for patients with heart failure and 15.6 per 1000 person–years for those without, a significant difference. After accounting for age, gender, Charlson comorbidity index, smoking status, body mass index, aspirin use and several cardiovascular risk factors, this equated to a hazard ratio of 1.92 for cancer in heart failure patients.
The study authors note that cancer incidence was similar in patients with versus without heart failure until approximately 1.5 years into the follow-up period, while the majority of healthcare demands of heart failure patients are known to occur during the first year of diagnosis. As a result, study author Véronique Roger (Mayo Clinic, Rochester, Minnesota) and team do not consider detection bias to be a major cause of the cancer diagnoses in heart failure patients.
They also did not find any indication of a link between the increased cancer risk and any cardiovascular medication, but Roger et al advise caution in view of their observational study design, “which limits a conclusive statement”.
Although the use of MI survivors has advantages, such that patients with and without heart failure have a common disease mechanism, risk factor profile and treatment modalities, Malhotra and Boffetta do not rule out the possibility of residual confounding. They point out that some potential confounders, such as smoking, were analysed in broad categories, and data on others, including alcohol intake, were missing.
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