Table 2.

Effect of low-dose ASA and clopidogrel on the risk of hemorrhagic stroke

	Cases (n = 70) n (%)	Controls (n = 1,000) n (%)	Odds ratioa (95 % CI)	P value
ASA
Non-use	20 (28.6)	164 (16.4)	1 (−)
Current use	44 (62.9)	753 (75.3)	0.88 (0.42–1.85)	0.74
Duration
< 1 month	3 (4.3)	29 (2.9)	0.77 (0.11–5.56)	0.80
1–12 months	16 (22.9)	201 (20.1)	0.71 (0.26–1.96)	0.51
≥ 1 year	25 (35.7)	523 (52.3)	1.15 (0.50–2.66)	0.74
Dose
75 mg/day	39 (55.7)	672 (67.2)	0.88 (0.41–1.86)	0.74
150 mg/day	1 (1.4)	70 (7.0)	0.19 (0.02–1.66)	0.13
300 mg/day	4 (5.7)	11 (1.1)	8.23 (1.77–38.26)	0.01
Recent use	2 (2.9)	44 (4.4)	0.51 (0.10–2.69)	0.43
Past use	4 (5.7)	39 (3.9)	1.02 (0.30–3.47)	0.98
Clopidogrel
Non-use	50 (71.4)	757 (75.7)	1 (−)
Current use	16 (22.9)	168 (16.8)	1.49 (0.70–3.17)	0.30
Duration
< 1 month	3 (4.3)	18 (1.8)	2.09 (0.32–13.67)	0.44
1–12 months	7 (10.0)	75 (7.5)	0.99 (0.35–2.78)	0.98
≥ 1 year	6 (8.6)	75 (7.5)	2.42 (0.81–7.22)	0.11
Dose
75 mg/day	16 (22.9)	156 (15.6)	1.61 (0.75–3.45)	0.22
≥ 150 mg/day	0 (0.0)	12 (1.2)
Recent use	3 (4.3)	19 (1.9)	1.34 (0.33–5.49)	0.68
Past use	1 (1.4)	56 (5.6)	0.22 (0.03–1.78)	0.16
Dual antiplatelet therapy
Non-use of both ASA and clopidogrel	13 (18.6)	96 (9.6)	1 (−)
Current use of both ASA and clopidogrel	7 (10.0)	91 (9.1)	1.20 (0.33–4.33)	0.78
Current ASA use and non-current clopidogrel use	37 (52.9)	662 (66.2)	1.04 (0.43–2.55)	0.93
Current clopidogrel use and non-current ASA use	9 (12.9)	77 (7.7)	2.20 (0.72–6.71)	0.17

ASA acetylsalicylic acid, CI confidence interval, NSAID non-steroidal anti-inflammatory drug, PCP primary care physician, PPI proton pump inhibitor

^aAdjusted according to age, sex, calendar year, length of follow-up, health services utilization (PCP visits, referrals and hospitalizations), smoking, type of coronary event, history of peptic ulcer disease, and use of PPIs, ASA, clopidogrel, NSAIDs and warfarin