Antithrombotic drugs and subarachnoid haemorrhage risk: A nationwide case-control study in Denmark

A Pottegård, L A García Rodríguez, F R Poulsen, J Hallas, D Gaist

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The study objective was to investigate the relationship between use of antithrombotic drugs and subarachnoid haemorrhage (SAH). We identified patients discharged from Danish neurosurgery units with a first-ever SAH diagnosis in 2000 to 2012 (n=5,834). For each case, we selected 40 age-, sex- and period-matched population controls. Conditional logistic regression models were used to estimate odds ratios (aOR), adjusted for comorbidity, education level, and income. Low-dose aspirin (ASA) use for < 1 month was associated with an increased risk of SAH (aOR 1.75, 95 % confidence interval [CI] 1.28-2.40). This aOR decreased to 1.26 (95 %CI: 0.98-1.63) with 2-3 months of ASA use, and approached unity with use for more than three months (1.11, 95 %CI 0.97-1.27). Analyses with first-time users confirmed this pattern, which was also observed for clopidogrel. ASA treatment for three or more years was associated with an aOR of SAH of 1.13 (95 %CI: 0.86-1.49). Short-term use (< 1 month) of vitamin K-antagonists (VKA) yielded an aOR of 1.85 (95 %CI 0.97-3.51) which dropped after 3+ years to 1.24, 95 %CI: 0.86-1.77. The risk of SAH was higher in subjects in dual antithrombotic treatment (aOR 2.08, 95 %CI: 1.26-3.44), and in triple antithrombotic treatment (aOR 5.74, 95 %CI: 1.76-18.77). In conclusion, use of aspirin,clopidogrel and VKA were only associated with an increased risk of SAH in the first three months after starting treatment. Long-term aspirin use carried no reduced SAH risk. Results should be interpreted cautiously due to their observational nature.

Original languageEnglish
JournalThrombosis and Haemostasis
Volume114
Issue number5
Pages (from-to)1064-1075
ISSN0340-6245
DOIs
Publication statusPublished - 23. Jul 2015

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Denmark
Case-Control Studies
Confidence Intervals
clopidogrel
Pharmaceutical Preparations
Logistic Models
Vitamin K 1
Population Control
Neurosurgery
Comorbidity
Odds Ratio
Education

Cite this

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title = "Antithrombotic drugs and subarachnoid haemorrhage risk: A nationwide case-control study in Denmark",
abstract = "The study objective was to investigate the relationship between use of antithrombotic drugs and subarachnoid haemorrhage (SAH). We identified patients discharged from Danish neurosurgery units with a first-ever SAH diagnosis in 2000 to 2012 (n=5,834). For each case, we selected 40 age-, sex- and period-matched population controls. Conditional logistic regression models were used to estimate odds ratios (aOR), adjusted for comorbidity, education level, and income. Low-dose aspirin (ASA) use for < 1 month was associated with an increased risk of SAH (aOR 1.75, 95 {\%} confidence interval [CI] 1.28-2.40). This aOR decreased to 1.26 (95 {\%}CI: 0.98-1.63) with 2-3 months of ASA use, and approached unity with use for more than three months (1.11, 95 {\%}CI 0.97-1.27). Analyses with first-time users confirmed this pattern, which was also observed for clopidogrel. ASA treatment for three or more years was associated with an aOR of SAH of 1.13 (95 {\%}CI: 0.86-1.49). Short-term use (< 1 month) of vitamin K-antagonists (VKA) yielded an aOR of 1.85 (95 {\%}CI 0.97-3.51) which dropped after 3+ years to 1.24, 95 {\%}CI: 0.86-1.77. The risk of SAH was higher in subjects in dual antithrombotic treatment (aOR 2.08, 95 {\%}CI: 1.26-3.44), and in triple antithrombotic treatment (aOR 5.74, 95 {\%}CI: 1.76-18.77). In conclusion, use of aspirin,clopidogrel and VKA were only associated with an increased risk of SAH in the first three months after starting treatment. Long-term aspirin use carried no reduced SAH risk. Results should be interpreted cautiously due to their observational nature.",
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Antithrombotic drugs and subarachnoid haemorrhage risk : A nationwide case-control study in Denmark. / Pottegård, A; García Rodríguez, L A; Poulsen, F R; Hallas, J; Gaist, D.

In: Thrombosis and Haemostasis, Vol. 114, No. 5, 23.07.2015, p. 1064-1075.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Antithrombotic drugs and subarachnoid haemorrhage risk

T2 - A nationwide case-control study in Denmark

AU - Pottegård, A

AU - García Rodríguez, L A

AU - Poulsen, F R

AU - Hallas, J

AU - Gaist, D

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N2 - The study objective was to investigate the relationship between use of antithrombotic drugs and subarachnoid haemorrhage (SAH). We identified patients discharged from Danish neurosurgery units with a first-ever SAH diagnosis in 2000 to 2012 (n=5,834). For each case, we selected 40 age-, sex- and period-matched population controls. Conditional logistic regression models were used to estimate odds ratios (aOR), adjusted for comorbidity, education level, and income. Low-dose aspirin (ASA) use for < 1 month was associated with an increased risk of SAH (aOR 1.75, 95 % confidence interval [CI] 1.28-2.40). This aOR decreased to 1.26 (95 %CI: 0.98-1.63) with 2-3 months of ASA use, and approached unity with use for more than three months (1.11, 95 %CI 0.97-1.27). Analyses with first-time users confirmed this pattern, which was also observed for clopidogrel. ASA treatment for three or more years was associated with an aOR of SAH of 1.13 (95 %CI: 0.86-1.49). Short-term use (< 1 month) of vitamin K-antagonists (VKA) yielded an aOR of 1.85 (95 %CI 0.97-3.51) which dropped after 3+ years to 1.24, 95 %CI: 0.86-1.77. The risk of SAH was higher in subjects in dual antithrombotic treatment (aOR 2.08, 95 %CI: 1.26-3.44), and in triple antithrombotic treatment (aOR 5.74, 95 %CI: 1.76-18.77). In conclusion, use of aspirin,clopidogrel and VKA were only associated with an increased risk of SAH in the first three months after starting treatment. Long-term aspirin use carried no reduced SAH risk. Results should be interpreted cautiously due to their observational nature.

AB - The study objective was to investigate the relationship between use of antithrombotic drugs and subarachnoid haemorrhage (SAH). We identified patients discharged from Danish neurosurgery units with a first-ever SAH diagnosis in 2000 to 2012 (n=5,834). For each case, we selected 40 age-, sex- and period-matched population controls. Conditional logistic regression models were used to estimate odds ratios (aOR), adjusted for comorbidity, education level, and income. Low-dose aspirin (ASA) use for < 1 month was associated with an increased risk of SAH (aOR 1.75, 95 % confidence interval [CI] 1.28-2.40). This aOR decreased to 1.26 (95 %CI: 0.98-1.63) with 2-3 months of ASA use, and approached unity with use for more than three months (1.11, 95 %CI 0.97-1.27). Analyses with first-time users confirmed this pattern, which was also observed for clopidogrel. ASA treatment for three or more years was associated with an aOR of SAH of 1.13 (95 %CI: 0.86-1.49). Short-term use (< 1 month) of vitamin K-antagonists (VKA) yielded an aOR of 1.85 (95 %CI 0.97-3.51) which dropped after 3+ years to 1.24, 95 %CI: 0.86-1.77. The risk of SAH was higher in subjects in dual antithrombotic treatment (aOR 2.08, 95 %CI: 1.26-3.44), and in triple antithrombotic treatment (aOR 5.74, 95 %CI: 1.76-18.77). In conclusion, use of aspirin,clopidogrel and VKA were only associated with an increased risk of SAH in the first three months after starting treatment. Long-term aspirin use carried no reduced SAH risk. Results should be interpreted cautiously due to their observational nature.

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DO - 10.1160/TH15-04-0316

M3 - Journal article

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JO - Thrombosis and Haemostasis

JF - Thrombosis and Haemostasis

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