Risk and predictors of subsequent cancers of patients with newly-diagnosed atrial fibrillation — A nationwide population-based study

Aims: Patients with atrial fibrillation (AF) may be at higher risk for cancer, possibly due to the presence of coexisting risk factors. In this study, we investigate the magnitude and predictors of this potential risk within a population-based study. Methods and results: The study cohort included 332,555 AF patients aged ≥20 years without past history of cancer. Standardized incidence ratio (SIR) was used as a measure of relative risk, comparing observed cancer incidence among patients with AF with that expected based on cancer incidence in the Taiwanese population. During the observation period, 22,911 incident cancers occurred with an incidence of 1.65%/year. Compared with the general population, AF patients had a significantly higher cancer risk with a SIR of 1.37 (95%CI = 1.36–1.39). Patients with new-onset AF had an elevated cancer risk which was highest within 1 year (SIR = 2.30; 95%CI, 2.25–2.36) and persisted beyond 10 years after AF was diagnosed (SIR = 1.18; 95%CI, 1.11–1.25). Age ≥ 65 years, male gender, hypertension, diabetes, chronic obstructive pulmonary disease (COPD) and liver cirrhosis were significantly associated with development of cancers among AF patients. The hazard ratio of cancers increased from 1.40 (95%CI = 1.28–1.53) for patients having 1 risk factor to 5.14 (95%CI = 4.03–6.06) for patients with 6 risk factors, in comparison to those without any risk factors. Conclusion: In the nationwide cohort study, we show that AF patients had a higher risk of cancer. Age, male gender, hypertension, diabetes, COPD and liver cirrhosis are important risk factors of cancer among AF patients. Prompt and detailed examinations may be considered for incident AF patients with multiple risk factors to early detect the occult malignancy.