Adverse effects

This chapter addresses special issues about adverse effects in Cochrane Reviews. Review authors may apply different eligibility criteria when attempting to identify adverse effects data. The two main aspects of eligibility that may differ are the types of study design and the types of participants. It is also possible that studies performed for a different purpose may be eligible for the adverse effects component of the review. When different eligibility criteria are used to address beneficial and adverse effects, it will often be necessary to conduct a separate search for the two (or more) sets of studies, and it may be necessary to plan different methods in other aspects such as assessing risk of bias. Because adverse effects data are often handled with less rigour than the primary beneficial outcomes of a study, review authors must recognize the possibility of poor case definition, inadequate monitoring and incomplete reporting when synthesizing data.