Canivano and Gracia [10]
|
None
|
N/A
|
N/A
| |
HTA report [8]
|
Quality assessment tool derived from QUADAS [19] and the Hayden checklist relating to prognostic studies [20]
|
Results of the quality assessment were presented
|
Impact commented on but sensitivity analyses not deemed possible.
| |
Krasopoulos et al. [11]
|
Study eligibility criterion: investigators to be blinded to patients’ aspirin status
|
Quality rating for risk of bias (A to D) but not explicit on how this was derived
|
No
|
Terminology used was confusing (e.g. ‘allocation of blindness’ and ‘compliance with blindness’). The term ‘allocation concealment’ used in the context of observational studies is not appropriate
|
Li et al. [15]
|
Study eligibility criterion: only those studies with verified compliance. Newcastle-Ottawa checklist [21] for cohort studies
|
Findings presented
|
No
| |
Pusch et al. [12]
|
None
|
N/A
|
N/A
| |
Sofi et al. [14]
|
Study eligibility criterion: prospective study design
|
N/A
|
N/A
| |
Snoep et al. [13]
|
Quality criteria relating to: control for confounders, measurement of exposure, completeness of follow-up and blinding, and, for case–control studies, matching and case definition
|
No
|
No
| |
Wisman et al. [16]
|
Modified QUADAS tool [19] (for quality assessment of diagnostic accuracy studies). 11 items assessed
|
Findings presented
|
Sensitivity analysis. Studies scoring ‘low risk of bias’ on eight or more of the quality items were considered to be good quality
| |