Table 3 Efficacy and safety of aspirin compared to placebo in preventing primary VTE.

From: Aspirin for the extended prevention of venous thromboembolism: a meta-analysis and trial sequential analysis

Variable	RR	[95% CI]	z	P-value	τ²	τ	I²	P at Q test	QoE
Efficacy
VTE^3,4,7	0.80	[0.70; 0.92]	− 3.13	0.001	0	0	45.8% [0.0%; 82.0%]	0.136	⊕⊕⊕⊖ Moderate^†
DVT^3,7	0.72	[0.56; 0.92]	− 2.61	0.009	0	0	0.0% [0.0%; 89.6%]	0.964	⊕⊕⊕⊖ Moderate^†
PE^3,7	0.73	[0.54; 0.97]	− 2.12	0.034	0.004	0.066	54.5% [0.0%; 87.0%]	0.111	⊕⊕⊕⊖ Moderate^*
All-cause mortality^3,7	0.97	[0.86; 1.09]	− 0.42	0.676	0	0	0.0% [0.0%; 89.6%]	0.839	⊕⊕⊖⊖ Low^†‡
Cardiovascular mortality^3,7	0.93	[0.79; 1.09]	− 0.85	0.398	0	0	0.0% [0.0%; 89.6%]	0.823	⊕⊕⊖⊖ Low^†‡
VTE-related mortality³	0.42	[0.24; 0.72]	− 3.16	0.001	0	0	0.0% [0.0%; 99.9%]	0.889	⊕⊕⊕⊖ Moderate^†
Safety
Bleeding^3,7	1.17	[1.01; 1.37]	2.15	0.031	0.009	0.097	19.8% [0.0%; 91.7%]	0.287	⊕⊕⊕⊖ Moderate^†
Major bleeding^3,7	1.13	[1.00; 1.28]	2.11	0.034	0.001	0.039	0.0% [0.0%; 89.6%]	0.382	⊕⊕⊕⊖ Moderate^†
Trasfusion³	1.04	[0.73; 1.49]	0.25	0.802	0.048	0.219	71.3% [0.0%; 93.5%]	0.062	⊕⊕⊖⊖ Low^*‡
Stroke^3,7	1.04	[0.75; 1.43]	0.25	0.803	0	0	0.0% [0.0%; 89.6%]	0.771	⊕⊕⊖⊖ Low^†‡
Cardiovascular AEs^3,7	0.98	[0.90; 1.06]	− 0.43	0.664	0	0	0.0% [0.0%; 89.6%]	0.456	⊕⊕⊖⊖ Low^†‡
Cardiac AEs^3,7	1.06	[0.96; 1.16]	1.26	0.207	0	0	0.0% [0.0%; 89.6%]	0.647	⊕⊕⊖⊖ Low^†‡
Myocardial infarction^3,7	1.02	[0.88; 1.18]	0.37	0.711	0	0	43.3% [0.0%; 83.0%]	0.171	⊕⊕⊖⊖ Low^†‡

RR relative risk, 95%CI 95% confidence interval, z z-score measures how many standard deviations a data point is from the mean, τ² between-study variance in random-effects meta-analysis, τ standard deviation estimate of effect sizes in random-effects meta-analysis, I² measures percentage variation across studies due to heterogeneity, Q test Cochran’s Q test assesses heterogeneity among study results, QoE quality of evidence. *Downgraded one level for inconsistency (such as heterogeneity of estimates of effects across trials)¹². ^†Although a low I² value usually suggests low heterogeneity, the quality of evidence for this observation remains uncertain. This uncertainty arises from a broad I² confidence interval, which hints at potential undetected heterogeneity. Despite the reported absence of between-study variance (τ² = 0) and no variation in effect estimates (τ = 0), and an I² of 0%, the QoE for the outcome was prudently downgraded one level¹². ^‡Downgraded one level for Imprecision (for example, 95% confidence intervals are wide and include or are close to null effect)¹². High QoE (⊕⊕⊕⊕): The authors are very confident that the true effect lies close to that of the estimate of the effect. Moderate QoE (⊕⊕⊕⊖): The authors are moderately confident in the effect estimate. The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low QoE (⊕⊕⊖⊖): The authors’ confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect¹².

Back to article page

Table 3 Efficacy and safety of aspirin compared to placebo in preventing primary VTE.

Search

Quick links