Risk of mortality in a cohort of patients newly diagnosed with chronic atrial fibrillation

Objective To estimate the mortality rate of patients newly diagnosed with chronic atrial fibrillation (AF) and compare it with the one in the general population. To evaluate the role of co-morbidity and other factors on the risk of dying among AF patients.Methods We used the General Practice Research Database in the UK to perform a retrospective cohort study. We followed a cohort of chronic AF patients (N = 1,035) and an age and sex matched cohort of 5,000 subjects sampled from the general population. We used all deceased AF patients as cases (n = 234) and the remaining AF patients as controls to perform a nested case-control analysis. We estimated mortality risk associated with AF using Cox regression. We computed mortality relative risks using logistic regression among AF patients.Results During a mean follow-up of two years, 393 patients died in the general population cohort and 234 in the AF cohort. Adjusted relative risk of death in the cohort of AF was 2.5 (95%CI 2.1 - 3.0) compared to the general population. Among AF patients, mortality risk increased remarkably with advancing age. Smokers carried a relative risk of dying close to threefold. Ischaemic heart disease was the strongest clinical predictor of mortality with a RR of 3.0 (95% CI; 2.1-4.1). Current use of calcium channel blockers, warfarin and aspirin was associated with a decreased risk of mortality.Conclusions Chronic AF is an important determinant of increased mortality. Major risk factors for mortality in the AF cohort were age, smoking and cardiovascular co-morbidity, in particular ischaemic heart disease.