Table 3.

Use of single and combined antithrombotic therapy and risk of serious upper gastrointestinal bleeding in a case–control study using research databases in Denmark, 2000–2004

Exposure group	Odds ratio (95% CI)
No antithrombotic use at all	Reference category
Aspirin use alone	2.4 (2.0–2.8)
Clopidogrel use alone	3.1 (1.7–5.6)
Aspirin and clopidogrel use	12.6 (6.6–24)

Note: Data from Hallas et al.¹⁸