Critical appraisal:Sandler RS, Halabi S, Baron JA, Budinger S, Paskett E, Keresztes R, et al 2003

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Risk of bias assessment: Randomised Controlled Trial (Cochrane risk of bias tool)

Random sequence generation
Describe the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups.Jutta's question mark icon.png
After the run-in period, eligible participants were randomly assigned to receive 325 mg of aspirin per day or identical-appearing placebo. Randomization was stratified according to the stage of cancer (Dukes’ A or B1 vs. Dukes’ B2 or C) and sex. The assignment was made centrally by the CALGB Statistical Center after eligibility and adherence were confirmed.
What was the risk of bias from the random sequence generation?Jutta's question mark icon.png
High
Allocation concealment
Describe the method used to conceal the allocation sequence in sufficient detail to determine whether intervention allocations could have been foreseen in advance of or during, enrolment.Jutta's question mark icon.png
After the run-in period, eligible participants were randomly assigned to receive 325 mg of aspirin per day or identical-appearing placebo. Randomization was stratified according to the stage of cancer (Dukes’ A or B1 vs. Dukes’ B2 or C) and sex. The assignment was made centrally by the CALGB Statistical Center after eligibility and adherence were confirmed.
What was the risk of bias from the allocation concealment?Jutta's question mark icon.png
Low
Blinding
Describe all measures used, if any, to blind outcome assessors from knowledge of which intervention a participant received. Provide any information relating to whether the intended blinding was effective.Jutta's question mark icon.png
Not described, but objective measures.
What was the risk of bias from the blinding of participants and personnel and outcome assessors?Jutta's question mark icon.png
Low
Incomplete outcome data
Describe the completeness of outcome data for each main outcome, including attrition and exlusions from the analysis. State whether attrition and exclusions were reported, the numbers in each intervention group (compared with total randomized participants), reasons for attrition/exclusions where reported, and any re-inclusions in analyses performed by the review authors.Jutta's question mark icon.png
Overall, 517 of the 635 randomized patients (81 percent) had at least one colonoscopic examination after randomization (258 in the placebo group and 259 in the aspirin group) (Table 2). The number of colonoscopic examinations was similar in the two groups (P=0.13 by the Wilcoxon test).
What was the risk of bias from incomplete outcome data?Jutta's question mark icon.png
Low
Selective outcome reporting
State how the possibility of selective outcome reporting was examined by the review authors and what was found.Jutta's question mark icon.png
Data on patients who did not have any adenomatous polyps were censored as of the date of the last colonoscopic examination.
What was the risk of bias from selective outcome reporting? Assessments should be made for each main outcome (or class of outcomes).Jutta's question mark icon.png
Low
Other sources of bias
Describe any other sources of biasJutta's question mark icon.png
What was the risk of bias from other sources?Jutta's question mark icon.png
Low
Overall risk of bias
High risk of bias Additional comments: Please replace this text and include any additional comments in regards to your risk of bias rating


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Article
Sandler RS, Halabi S, Baron JA, Budinger S, Paskett E, Keresztes R, et al. A randomized trial of aspirin to prevent colorectal adenomas in patients with previous colorectal cancer. N Engl J Med 2003 Mar 6;348(10):883-90 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12621132.
Assigned to
User:Albert.chetcuti
Topic area
Guidelines:Colorectal cancer
Clinical question
Form
Form:Quality appraisal rct-cochrane


Section below only relevant for Cancer Council Project Officer

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