Atrial Fibrillation, Oral Anticoagulants, and Concomitant Active Cancer: Benefits and Risks.

Aim To determine to what extent active cancer influences the benefit-risk relationship among patients with atrial fibrillation receiving oral anticoagulants for stroke prevention. Methods In this cohort study of all patients with atrial fibrillation in the Swedish Patient register during 2006 to 2017, 8,228 patients with active cancer and 323,394 without cancer were followed up to 1 year after initiation of oral anticoagulants. Cox regression models, adjusting for confounders and the competing risk of death, were used to assess risk of cerebrovascular and bleeding events. Results Among patients treated with oral anticoagulants, the risk for cerebrovascular events did not differ between cancer patients and noncancer patients (subhazard ratio [sHR]: 1.12, 95% confidence interval [CI]: 0.98-1.29). Cancer patients had a higher risk for bleedings (sHR: 1.69, CI: 1.56-1.82), but not for fatal bleedings (sHR: 1.17, CI: 0.80-1.70). Use of nonvitamin K oral anticoagulants was associated with lower risk of both cerebrovascular events and bleedings compared with warfarin. Conclusion Patients with atrial fibrillation and active cancer appear to have similar net cerebrovascular benefit of oral anticoagulant treatment to patients without cancer, despite an increased risk of nonfatal bleedings. Use of nonvitamin K oral anticoagulants was associated with lower risk of all studied outcomes.

Net benefit of oral anticoagulants in patients with atrial fibrillation and active cancer: a nationwide cohort study.

AIMS: To estimate the net cerebrovascular benefit of prophylactic treatment with oral anticoagulants (OACs) in patients with atrial fibrillation (AF) and active cancer. METHODS AND RESULTS: We included all Swedish patients who had been diagnosed with AF in a hospital or in a hospital-associated outpatient unit between 1 July 2005 and 1 October 2017. Patients with active cancer (n = 22 596) and without cancer (n = 440 848) were propensity score matched for the likelihood of receiving OACs at baseline. At baseline, 38.3% of cancer patients with AF and high stroke risk according to CHA2DS2-VASc score received OACs. There was a net benefit of OACs, assessed by the composite outcome of ischaemic stroke, extracranial arterial thromboembolism, all major bleedings, and death, both among patients with active cancer [hazard ratio (HR): 0.81, confidence interval (CI): 0.78-0.85] and among patients without cancer (HR: 0.81, CI: 0.80-0.82). When limiting follow-up to 1 year to minimize the effects of possible treatment cross-over and additionally accounting for death as a competing risk in cancer patients, a net cerebrovascular benefit regarding ischaemic stroke or intracranial bleeding was observed for OACs [subhazard ratio (sHR): 0.67, CI: 0.55-0.83]. A net cerebrovascular benefit was also seen for non-vitamin K antagonist OACs over warfarin after competing risk analyses in cancer patients (sHR: 0.65, CI: 0.48-0.88). CONCLUSION: Patients with AF and active cancer benefit from OAC treatment.

Comparison of the ATRIA, CHADS2, and CHA2DS2-VASc stroke risk scores in predicting ischaemic stroke in a large Swedish cohort of patients with atrial fibrillation.

AIMS: Better stroke risk prediction is needed to optimize the anticoagulation decision in atrial fibrillation (AF). The ATRIA stroke risk score (ATRIA) was developed and validated in two large California community AF cohorts. We compared the performance of the ATRIA, CHADS2, and CHA2DS2-VASc scores in a national Swedish AF (SAF) cohort. METHODS AND RESULTS: We examined all Swedish patients hospitalized, or visiting a hospital-based outpatient clinic, with a diagnosis of AF from July 2005 through December 2010. Variables were determined from comprehensive national databases. Risk scores were assessed via C-index (C) and net reclassification improvement (NRI). The cohort included 152 153 AF patients not receiving warfarin. Overall, 11 053 acute ischaemic strokes were observed with mean rate 3.2%/year, higher than the 2%/year in the California cohorts. Using entire point scores, ATRIA had a good C of 0.708 (0.704-0.713), significantly better than CHADS2 0.690 (0.685-0.695) or CHA2DS2-VASc 0.694 (0.690-0.700). Using published cut-points for low/moderate/high risk, C deteriorated but ATRIA remained superior. Net reclassification improvement favoured ATRIA 0.16 (0.14-0.17) vs. CHADS2 and 0.21 (0.20-0.23) vs. CHA2DS2-VASc. Net reclassification improvement decreased when cut-points were altered to better fit the cohort's stroke rates. CONCLUSION: In this SAF cohort, the ATRIA score predicted ischaemic stroke risk better than CHADS2 or CHA2DS2-VASc. However, relative performance of the categorical scores varied by population stroke rates. Score cut-points may need to be optimized to better fit local population stroke rates.