Critical appraisal:Rothwell PM, Wilson M, Elwin CE, Norrving B, Algra A, Warlow CP, et al 2010 4

Was an adequate search strategy used?

Very thorough – included appropriate search terms and databases

Were the inclusion criteria appropriate and applied in an unbiased way?

Yes – pre-specified inclusion criteria applied independently by two people

Were the studies assessed for quality (relating to the minimisation of biases)?

Adequate – some problems with quality issues or assessed by one person only

Were the characteristics and results of individual studies appropriately summarised?

Yes – summary descriptive tables of subjects, interventions, outcomes etc are provided and estimates of treatment effect displayed

Were the methods used for pooling the data appropriate?

Yes

If there was heterogeneity, were sources of heterogeneity explored?

Yes

Overall risk of bias

Moderate risk of bias

Additional comments: Please replace this text and include any additional comments in regards to your risk of bias rating

This appraisal has been completed.

Article: Rothwell PM, Wilson M, Elwin CE, Norrving B, Algra A, Warlow CP, et al. Long-term effect of aspirin on colorectal cancer incidence and mortality: 20-year follow-up of five randomised trials. Lancet 2010 Nov 20;376(9754):1741-50 Available from: http://www.ncbi.nlm.nih.gov/pubmed/20970847.

Assigned to

User:Albert.chetcuti

Topic area

Guidelines:Colorectal cancer/Prevention

Clinical question

Section below only relevant for Cancer Council Project Officer