Stroke incidence and competing risks for people with heart failure and atrial fibrillation in primary care: cohort study

Talk Code: 
Nicholas Jones
Nicholas R Jones, Margaret Smith, Sarah Lay-Flurrie, Andrea K Roalfe, Yaling Yang, FD Richard Hobbs and Clare J Taylor
Author institutions: 
University of Oxford Nuffield Department of Primary Care Health Sciences


Atrial fibrillation (AF) is associated with a five-fold increased risk of stroke, but the risk of stroke in people with heart failure (HF), with or without AF, is less well defined. This information is important to inform decisions around anticoagulation and stroke prevention.


Primary care cohort study of people aged ≥45 years using Clinical Practice Research Datalink data from England between January 2000 and December 2018, linked to inpatient Hospital Episode Statistics. Cox proportional hazards and Fine and Gray competing risks models were used to examine the association between HF, AF or both and incidence of first stroke, adjusting for other established cardiovascular risk factors.


We included 2,381,941 participants (mean age 57 years), of whom 80,243 had HF only, 127,588 had AF only and 61,448 had both AF and HF. During follow-up (median 6.62 years) 93,665 patients (3.93%) had a first stroke and 314,042 (13.18%) died. Among people with HF, with or without AF, 12,386 (8.7%) suffered a first stroke and 82,806 (58.4%) died. Stroke was the primary cause of death in 9.55% (n=3,777) of people with AF, 5.82% of people with AF and HF (n=2,470) and 3.94% (n=1,592) of those with HF alone.In an unadjusted Cox model, stroke risk was highest among people with HF and AF (HR 8.93, 95%CI: 8.71-9.16), but also elevated for people with AF only (HR 7.12, 95%CI: 7.00-7.25), or HF only (HR 4.77, 95%CI: 4.64-4.90) compared to the general population. However, in the fully adjusted Cox model, stroke risk was highest among people with AF alone (HR 2.38, 95%CI: 2.33- 2.43), followed by HF and AF (HR 2.16, 95%CI: 2.10-2.22) and HF alone (HR 1.40, 95%CI: 1.36-1.45). Accounting for competing risk using the Fine and Gray model did not change the stroke risk for people with AF alone, but led to significant attenuation in risk for people with HF and AF (HR 1.48, 95%CI: 1.44-1.53), while people with HF alone were at little increased risk compared to the general population (HR 1.04, 95%CI: 1.01-1.08). For people with HF alone or HF with AF, the greatest relative increase in risk was among those aged under 65 years who were not treated with anticoagulation, compared to the general population of the same age.


People with HF are at an increased risk of stroke, but often have a poor prognosis, which means stroke incidence is lower than anticipated. Clinicians may need to take account an individual patient’s prognosis as well as their stroke and bleeding risk when considering the potential benefits of anticoagulation. Future research could refine stroke risk scores to incorporate competing risks when considering anticoagulation in people with AF and HF.

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Nicholas Jones
Funding acknowledgement: 
NRJ is a Wellcome Trust Doctoral Research Fellow (grant no. 203921/Z/16/Z) and received support for this projected from the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) Oxford. FDRH acknowledges support from the NIHR School for Primary Care Research, NIHR ARC Oxford and Thames Valley, and the NIHR Oxford BRC. CJTT is a NIHR Academic Clinical Lecturer. The funders did not have any role in the design of the study, analysis and interpretation of the data, or writing of the results for publication. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care. This work uses data provided by patients and collected by the NHS as part of their care and support and would not have been possible without access to this data. The NIHR recognizes and values the role of patient data, securely accessed, and stored, both in underpinning and leading to improvements in research and care.