Table 12Detailed SOE for aspirin versus placebo in adults with asymptomatic or symptomatic PAD at 2+ years

Population
Study Design
Number of Studies (Total Patients)
Risk of BiasConsistencyDirectnessPrecisionSOE and Magnitude of Effect Effect Estimate (95% CI)
All-cause mortality
Asymptomatic
RCT
2 (3986)
2 low riskConsistentDirectPreciseHR 0.93 (0.71 to 1.24)
HR 0.95 (0.77 to 1.16)
No difference
High SOE
Nonfatal MI
Asymptomatic
RCT
2 (3986)
2 low riskConsistentDirectPreciseHR 0.98 (0.68 to 1.42)
HR 0.91 (0.65 to 1.29)
No difference
High SOE
IC
RCT
1 (181)
1 moderate riskNADirectImpreciseHR 0.18 (0.04 to 0.82)
Favors aspirin
Low SOE
CLI
Observational
1 (113)
1 high riskNADirectUnknownNo difference between aspirin (1.2%) and no-aspirin (5.9%) groups
Insufficient SOE
Nonfatal stroke
Asymptomatic
RCT
2 (3986)
2 low riskConsistentDirectPreciseHR 0.71 (0.44 to 1.14)
HR 0.97 (0.62 to 1.53)
No difference
High SOE
IC
RCT
1 (181)
1 moderate riskNADirectImpreciseHR 0.54 (0.16 to 1.84)
Inconclusive
Insufficient SOE
CLI
Observational
1 (113)
1 high riskNADirectUnknownNo difference between aspirin (2.5%) and no-aspirin (8.8%) groups
Insufficient SOE
Cardiovascular mortality
Asymptomatic
RCT
2 (3986)
2 low riskConsistentDirectImpreciseHR 1.23 (0.79 to 1.92)
HR 0.95 (0.77 to 1.17)
No difference
Moderate SOE
IC
RCT
1 (181)
1 moderate riskNADirectImpreciseHR 1.21 (0.32 to 4.55)
Inconclusive
Insufficient SOE
CLI
Observational
1 (113)
1 high riskNADirectUnknownNo difference between aspirin (33%) and no-aspirin (26%) groups
Insufficient SOE
Composite vascular events
Asymptomatic
RCT
2 (3986)
2 low riskConsistentDirectPreciseHR 0.98 (0.76 to 1.26)
HR 1.00 (0.85 to 1.17)
No difference
High SOE
IC
RCT
1 (181)
1 moderate riskNADirectImpreciseHR 0.35 (0.15 to 0.82)
Favors aspirin
Low SOE
Modifiers of effectiveness (subgroups)
Asymptomatic IC-CLI
RCT
3 (4202)
2 low risk, 1 moderate riskNANANANo differences in outcomes by age, sex, or baseline ABI in aspirin studies
Insufficient SOE
Safety concerns
Asymptomatic or IC
RCT
3 (4167)
2 low risk, 1 moderate riskNANANABleeding rates slightly higher in aspirin group (2 to 4%) compared to placebo (0 to 6%)
Insufficient SOE
Functional outcomes Quality of life Safety concerns (subgroups)
0NANANANAInsufficient SOE

Abbreviations: ABI=ankle-brachial index; CI=confidence interval; CLI=critical limb ischemia; HR=hazard ratio; IC=intermittent claudication; NA=not applicable; Obs=observational; PTA=percutaneous transluminal angioplasty; RCT=randomized controlled trial; SOE=strength of evidence.

From: Results

Cover of Treatment Strategies for Patients With Peripheral Artery Disease
Treatment Strategies for Patients With Peripheral Artery Disease [Internet].
Comparative Effectiveness Reviews, No. 118.
Jones WS, Schmit KM, Vemulapalli S, et al.

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