Predicting outcomes in patients with cancer and atrial fibrillation

Background: The role of cancer-specific factors for ischemic stroke and mortality in patients with cancer and atrial fibrillation (AF) is unknown. We evaluated the utility of a previously validated risk tool for venous thromboembolism (VTE) in cancer outpatients [Khorana score (KS)] in predicting stroke and mortality in cancer patients with AF. Methods: We conducted a retrospective cohort study of patients with cancer and AF at the Cleveland Clinic from 2008 to 2014. Outcomes, CHADS2, CHA2DS2-VASc, and KS scores were calculated from date of cancer diagnosis. Prognostic factors were identified with Fine and Gray regression (for stroke) or Cox proportional hazards analysis (for mortality). Results: The study population comprised 1181 patients. Genitourinary (19%), lung (18%), and gastrointestinal (13%) were the most frequent cancers. Overall, 67% had CHADS2 >= 2, 57% had an intermediate KS (1-2), and 7% high KS (>= 3). Median follow up was 26.5 months (range 0.03-76). At a median of 8.2 months (range 0-61), 45 patients (3.8%) developed a stroke and 418 (35%) died. In multivariable analysis a high KS (HR 4.5, 95% CI 3.2-6.3, p < 0.001) was associated with a quadruple risk of death and every point increase in CHADS2 score had a 20% increased risk of death (HR 1.19, 95% CI 1.1-1.2, p < 0.001). The addition of KS did not improve risk stratification for ischemic stroke to CHADS2. Conclusion: In patients with cancer and AF, CHADS2 and CHA2DS2-VASc but not KS were predictive of ischemic stroke. A high KS represented a unique predictor of mortality beyond traditional risk scores.