Predicting outcomes in patients with cancer and atrial fibrillation

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.

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).

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.

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.