Table 3.
Main and Stratified Analyses of the Effect of Aspirin Dose on Cardiovascular Outcomes
| Group | Main Analyses | Primary Prevention Only | Secondary Prevention Only | Cohort Study Only | RCT Only | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | RR (95% CI) | I2 | n | RR (95% CI) | I2 | n | RR (95% CI) | I2 | n | RR (95% CI) | I2 | n | RR (95% CI) | I2 | |
| All-Cause Mortality | |||||||||||||||
| ≤100 mg | 13 | 0.89 (0.72–1.10) | 64% | 5 | 0.94 (0.77–1.14) | 0% | 4 | 0.80 (0.58–1.11) | 64% | 4 | 0.71 (0.42–1.19) | 89% | 9 | 0.96 (0.82–1.12) | 0% |
| 101–325 mg | 4 | 0.89 (0.61–1.30) | 83% | 1 | 1.29 (0.90–1.84) | NA | 3 | 0.74 (0.52–1.03) | 39% | 3 | 0.89 (0.59–1.35) | 88% | 1 | 0.83 (0.27–2.51) | NA |
| >325 mg | 8 | 0.96 (0.85–1.08) | 0% | 1 | 0.78 (0.07–8.66) | NA | 6 | 1.11 (0.76–1.60) | 0% | 3 | 1.32 (0.86–2.04) | 0% | 5 | 0.93 (0.82–1.06) | 0% |
| All Studies | 25 | 0.93 (0.81–1.07) | 57% | 7 | 1.01 (0.85–1.19) | 0% | 13 | 0.82 (0.69–0.98) | 27% | 10 | 0.88 (0.67–1.14) | 81% | 15 | 0.94 (0.85–1.04) | 0% |
| Cardiovascular Mortality | |||||||||||||||
| ≤100 mg | 9 | 0.81 (0.52–1.25) | 65% | 5 | 0.74 (0.36–1.52) | 49% | 2 | 0.93 (0.61–1.43) | 0% | 2 | 0.62 (0.10–4.02) | 93% | 7 | 0.92 (0.64–1.32) | 25% |
| 101–325 mg | 2 | 1.52 (1.13–2.06) | 0% | 1 | 1.22 (0.65–2.29) | NA | 2 | 0.98 (0.67–1.43) | 0% | 1 | 1.52 (1.11–2.07) | NA | 1 | 1.66 (0.38–7.27) | NA |
| >325 mg | 5 | 0.89 (0.77–1.04) | 0% | 1 | 1.69 (0.15–18.96) | NA | 4 | 0.98 (0.57–1.68) | 0% | 1 | 1.77 (0.35–8.92) | NA | 4 | 0.89 (0.76–1.04) | 0% |
| All Studies | 16 | 0.98 (0.76–1.25) | 54% | 7 | 0.98 (0.63–1.53) | 26% | 8 | 0.96 (0.75–1.24) | 0% | 4 | 1.01 (0.50–2.05) | 82% | 12 | 0.91 (0.80–1.04) | 0% |
| Myocardial Infarction | |||||||||||||||
| ≤100 mg | 10 | 0.77 (0.53–1.11) | 68% | 6 | 1.12 (0.81–1.56) | 47% | 2 | 0.45 (0.22–0.92) | 0% | 2 | 0.94 (0.30–3.00) | 91% | 8 | 0.72 (0.48–1.08) | 58% |
| 101–325 mg | 3 | 0.98 (0.31–3.12) | 88% | 2 | 0.88 (0.20–3.87) | 94% | 2 | 1.28 (0.41–3.98) | 0% | 1 | 1.81 (1.36–2.41) | NA | 2 | 0.61 (0.19–1.95) | 53% |
| >325 mg | 5 | 0.85 (0.73–0.99) | 0% | 1 | 1.77 (0.35–8.89) | NA | 3 | 0.78 (0.41–1.49) | 0% | 1 | 1.76 (0.35–8.83) | NA | 4 | 0.85 (0.73–0.99) | 0% |
| All Studies | 18 | 0.84 (0.65–1.09) | 71% | 9 | 1.06 (0.75–1.51) | 70% | 7 | 0.68 (0.44–1.06) | 0% | 4 | 1.26 (0.70–2.27) | 80% | 14 | 0.76 (0.59–0.97) | 47% |
| Stroke | |||||||||||||||
| ≤100 mg | 12 | 0.81 (0.68–0.97) | 0% | 6 | 0.81 (0.55–1.19) | 49% | 2 | 0.83 (0.60–1.15) | 0% | 2 | 1.50 (0.83–2.73) | 0% | 10 | 0.76 (0.63–0.92) | 0% |
| 101–325 mg | 3 | 1.57 (1.08–2.30) | 0% | 2 | 1.52 (1.01–2.27) | 0% | 1 | 1.84 (0.59–5.73) | NA | 1 | 1.56 (0.97–2.50) | NA | 2 | 1.60 (0.85–3.03) | 0% |
| >325 mg | 6 | 1.20 (0.91–1.59) | 0% | 2 | 1.30 (0.24–7.05) | 0% | 3 | 1.51 (0.55–4.14) | 0% | 1 | 1.18 (0.09–16.05) | NA | 5 | 1.20 (0.91–1.59) | 0% |
| All Studies | 21 | 0.98 (0.82–1.16) | 20% | 10 | 0.98 (0.71–1.35) | 46% | 6 | 0.92 (0.69–1.24) | 0% | 4 | 1.53 (1.06–2.21) | 0% | 17 | 0.90 (0.76–1.07) | 9% |
RCT = Randomized Controlled Trial; n = Number of studies contributing data; NA = Not Appropriate; RR = Pooled Risk Ratio;
95% CI = 95% Confidence Interval