Critical appraisal:Stolwijk JA, Langers AM, Hardwick JC, Veenendaal RA, Verspaget HW, van Hogezand RA, et al 2013 2

Risk of bias assessment: cohort study (risk factors)

Bias in selection of participants into study

Selection of the exposed and non-exposed cohorts

Drawn from the same population (low risk)

Bias due to error in exposure measurement

Measurement of exposure

Objective measurements from pre-existing records or <img alt="File:Jutta's info icon.png" src="/australiawiki_test/images/d/d9/Jutta%27s_info_icon.png" width="16" height="16"> baseline (Existing at or before baseline, where baseline is the time at which a participant is recorded to have entered the cohort or, if obtained after baseline, before onset of symptoms of the outcome or any likely effect of the developing outcome on the exposure) physical or biological assessment blind to outcome status (low risk)

Bias due to error in outcome measurement

Measurement of outcome

Objective outcome measurement possibly influenced by exposure (moderate risk)

Was outcome of interest absent at the time to which the exposure refers?

Yes (low risk)

Was follow-up long enough for outcome to occur as a consequence of measured exposure? (Requires prior specification of a sufficient follow-up period)

Yes (low risk)

Bias due to non-participation

Participation rate in cohort

Participation rate in exposed cohort ≤10 percentage points different from non-exposed cohort OR exposed and non-exposed are from the same cohort (low risk)

Bias due to missing data

Completeness of follow-up of cohort

Active or passive follow-up of participants with methods for ascertainment of outcome and death clearly described AND with methods for ascertainment of emigration from population-at-risk clearly described or censoring at date of last follow-up OR there is a plausible estimate of >90% follow-up (low risk)

Accuracy of dates of outcome or censoring

Dates of outcome or censoring ascertained to within one year (low risk)

Difference in follow-up between exposed and non-exposed members of cohort

Follow-up methods are the same and likely to achieve the same completeness of follow-up in exposed and non-exposed participants (low risk)

Difference in missing data for exposure between those with or without the outcome

Difference in missing data for exposure ≥10 to <20 percentage points (moderate risk)

Bias due to confounding

Comparability of exposed and non-exposed cohorts with respect to potentially important confounding variables (Requires prior specification of potentially important confounders)

No potentially important confounders or only age controlled by design or in analysis OR insufficient information to tell (high risk)

Analysis bias

Covariates are appropriately included in statistical analysis models

Variables measuring the same underlying concept or lying in the same causal pathway ARE included together as covariates in statistical analysis models OR insufficient information to tell (high risk)

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

This appraisal has been completed.

Article

Stolwijk JA, Langers AM, Hardwick JC, Veenendaal RA, Verspaget HW, van Hogezand RA, et al. A thirty-year follow-up surveillance study for neoplasia of a dutch ulcerative colitis cohort. ScientificWorldJournal 2013;2013:274715 Available from: http://www.ncbi.nlm.nih.gov/pubmed/24379739.

Assigned to

User:Albert.chetcuti

Topic area

Guidelines:Colorectal cancer/Colonoscopy surveillance

Clinical question

• What is the most appropriate time interval for surveillance in IBD patients?

Form

Form:Quality appraisal cohort risk factors

Section below only relevant for Cancer Council Project Officer

Edit appraisal assignment