AF is an established independent risk factor for ischemic stroke as shown by many
previous studies [
[1]
]. Anticoagulants are highly effective in reducing the risk of subsequent stroke in
AF patients [
[2]
]. They have been recommended by the American Heart Association to prevent ischemic
stroke [
[3]
]. Some AF patients will develop ischemic stroke although they are treated with anticoagulants
[
- January C.T.
- Wann L.S.
- Alpert, J.S.
- Calkins H.
- Cigarroa J.E.
- Cleveland Jr., J.C.
- et al.
2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation:
executive summary: a report of the American College of Cardiology/American Heart Association
Task Force on Practice Guidelines and the Heart Rhythm Society.
Circulation. 2014; 130: 2071-2104
[4]
]. It is thus important to identify risk factors that are associated with an increased
risk of stroke in AF patients. The incidence of stroke was found to be somewhat higher
among AF patients in Asian countries as compared to patients from the USA and European
countries [
[5]
]. However, the different welfare systems as well as the various guidelines for the
management of AF patients in different countries preclude a concrete conclusion whether
there are ethnic differences in the risk of stroke in AF patients. In this study,
we will explore whether immigrants with AF have a different risk of stroke as compared
to native Swedes. (See Table 1.)
Table 1Adjusted hazard ratio for associations between sociodemographic characteristics and
subsequent stroke.
| No. of individuals | Person-years of follow-up | No. of strokes | Rate per 100 person-years | Model 1 | Model 2 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| HR | 95% CI | HR | 95% CI | |||||||
| Birth country or region | ||||||||||
| Sweden | 126,897 | 356,940 | 8079 | 2.3 | Reference | Reference | ||||
| Scandinavia | 7387 | 21,102 | 486 | 2.3 | 1.1 | 1.0 | 1.2 | 1.0 | 1.0 | 1.2 |
| Western Europe | 1861 | 5122 | 115 | 2.2 | 0.9 | 0.8 | 1.1 | 1.0 | 0.8 | 1.2 |
| East Europe and Soviet | 3894 | 10,937 | 251 | 2.3 | 1.1 | 1.0 | 1.3 | 1.1 | 1.0 | 1.3 |
| Mediterranean | 404 | 1100 | 26 | 2.4 | 1.3 | 0.9 | 2.0 | 1.3 | 0.9 | 1.9 |
| Turkey and Middle East | 1562 | 4574 | 86 | 1.9 | 1.3 | 1.0 | 1.6 | 1.3 | 1.0 | 1.6 |
| India, Pakistan, Afghanistan | 130 | 362 | 7 | 1.9 | 1.3 | 0.6 | 2.9 | 1.3 | 0.6 | 3.0 |
| East and Southeast Asia | 169 | 475 | 8 | 1.7 | 1.0 | 0.5 | 2.2 | 1.0 | 0.5 | 2.1 |
| Chile | 128 | 386 | 14 | 3.6 | 2.0 | 1.1 | 3.5 | 1.9 | 1.1 | 3.4 |
| Others | 737 | 2152 | 29 | 1.3 | 0.8 | 0.5 | 1.2 | 0.8 | 0.6 | 1.2 |
| Age at diagnosis (years) | ||||||||||
| <60 | 23,691 | 78,191 | 535 | 0.7 | Reference | Reference | ||||
| 60–69 | 35,344 | 106,834 | 1471 | 1.4 | 1.9 | 1.7 | 2.1 | 1.8 | 1.6 | 2.0 |
| 70–79 | 43,094 | 123,757 | 2848 | 2.3 | 3.1 | 2.8 | 3.4 | 2.8 | 2.6 | 3.1 |
| 80+ | 41,040 | 94,372 | 4247 | 4.5 | 5.5 | 5.0 | 6.0 | 5.0 | 4.5 | 5.5 |
| Gender | ||||||||||
| Male | 80,033 | 229,045 | 4165 | 1.8 | Reference | Reference | ||||
| Female | 63,136 | 174,110 | 4936 | 2.8 | 1.2 | 1.1 | 1.2 | 1.2 | 1.1 | 1.2 |
| Education (years) | ||||||||||
| ≤9 | 60,372 | 165,115 | 4711 | 2.9 | Reference | |||||
| 10–11 | 36,879 | 104,207 | 2169 | 2.1 | 0.9 | 0.9 | 1.0 | |||
| 12+ | 45,918 | 133,833 | 2221 | 1.7 | 0.9 | 0.8 | 0.9 | |||
| Diabetes | ||||||||||
| No | 132,280 | 372,608 | 8216 | 2.2 | Reference | |||||
| Yes | 10,889 | 30,547 | 885 | 2.9 | 1.3 | 1.2 | 1.4 | |||
| Obesity | ||||||||||
| No | 141,283 | 398,058 | 8976 | 2.3 | Reference | |||||
| Yes | 1886 | 5097 | 125 | 2.5 | 1.1 | 0.9 | 1.3 | |||
| Alcoholism | ||||||||||
| No | 139,534 | 393,135 | 8852 | 2.3 | Reference | |||||
| Yes | 3635 | 10,020 | 249 | 2.5 | 1.1 | 0.9 | 1.2 | |||
| Hypertension | ||||||||||
| No | 5224 | 15,612 | 106 | 0.7 | Reference | |||||
| Yes | 137,945 | 387,543 | 8995 | 2.3 | 1.9 | 1.6 | 2.3 | |||
| All | 143,169 | 403,155 | 9101 | 2.3 | ||||||
Bold type shows that 95% confidence intervals do not overlap with 1.00.
HR, hazard ratio; CI, confidence interval.
Keywords
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References
- Atrial fibrillation as an independent risk factor for stroke: the Framingham study.Stroke. 1991; 22: 983-988
- New oral anticoagulants for atrial fibrillation.Circulation. 2012; 126: 133-137
- 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.Circulation. 2014; 130: 2071-2104
- Oral anticoagulation in atrial fibrillation.Cardiovasc Hematol Agents Med Chem. 2014; 12: 34-41
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- Lactose intolerance and risk of lung, breast and ovarian cancers: aetiological clues from a population-based study in Sweden.Br J Cancer. 2015; 112: 149-152
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Article info
Publication history
Published online: September 01, 2016
Received:
August 17,
2016
Identification
Copyright
© 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.
