Association between antithrombotic treatment and hemorrhagic stroke in patients with atrial fibrillation-a cohort study in primary care.
OBJECTIVE
The objective of this study was to study the association between antithrombotic treatment and risk of hemorrhagic stroke (HS) in patients with atrial fibrillation (AF) treated in primary health care.


METHODS
Study population included all adults (n = 12,215) 45 years and older diagnosed with AF at 75 primary care centers in Sweden 2001-2007. Outcome was defined as a first hospital episode with a discharge episode of HS after the AF diagnosis. Association between HS and persistent treatment with antithrombotic agents (warfarin, acetylsalicylic acid (ASA), clopidogrel) was explored using Cox regression analysis, with hazard ratios (HRs) and 95 % CIs. Adjustment was made for age, socioeconomic status, and co-morbid cardiovascular conditions.


RESULTS
During a mean of 5.8 years (SD 2.4) of follow-up, 162 patients (1.3 %; 67 women and 95 men) with HS were recorded. The adjusted risk associated with persistent warfarin treatment compared to no antithrombotic treatment consistently showed no increased HS risk, HR for women 0.53 (95 % CI 0.23-1.27) and for men 0.55 (95 % CI 0.29-1.04); corresponding HRs for ASA were, for women, 0.45 (95 % CI 0.14-1.44) and, for men, 0.56 (95 % CI 0.24-1.29).


CONCLUSIONS
In this clinical setting, we found no evidence pointing to an increased risk of HS with antithrombotic treatment.
Division of Family Medicine, Department of Neurobiology, Care Science and Society, Karolinska Institutet, Alfred Nobels Allé 12, 141 83, Huddinge, Sweden. per.wandell@ki.se.
Per
http://orcid.org/0000-0001-5169-2965
P
Wändell
Division of Family Medicine, Department of Neurobiology, Care Science and Society, Karolinska Institutet, Alfred Nobels Allé 12, 141 83, Huddinge, Sweden.|Department of Medical Sciences, Cardiovascular Epidemiology, Uppsala University, Uppsala, Sweden.
Axel C
AC
Carlsson
Department of Emergency Medicine, Karolinska University Hospital, Stockholm, Sweden.|Department of Internal Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.
Martin
M
Holzmann
Department of Medical Sciences, Cardiovascular Epidemiology, Uppsala University, Uppsala, Sweden.|School of Health and Social Studies, Dalarna University, Falun, Sweden.
Johan
J
Ärnlöv
Center for Primary Health Care Research, Lund University, Malmö, Sweden.
Sven-Erik
SE
Johansson
Center for Primary Health Care Research, Lund University, Malmö, Sweden.
Jan
J
Sundquist
Center for Primary Health Care Research, Lund University, Malmö, Sweden.
Kristina
K
Sundquist
D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001241:Aspirin / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy*; D000077144:Clopidogrel; D015331:Cohort Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D020300:Intracranial Hemorrhages / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011320:Primary Health Care; D020521:Stroke / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D014859:Warfarin / Q000627:therapeutic use
D000925:Anticoagulants; D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
Anticoagulants; Atrial fibrillation; Cardiovascular co-morbidity; Gender; Hemorrhagic stroke; Mortality