14.2.3  Separate review for adverse effects

The third strategy is to undertake a separate review of adverse effects alone. This might be appropriate for an intervention that is given for a variety of diseases or conditions, yet whose adverse effect profile might be expected to be similar in different populations and settings. For example, aspirin is used in a wide variety of patients, such as those with stroke, or peripheral vascular disease, and also in those with coronary artery disease. The main effects of aspirin on outcomes relevant to these different conditions would typically be addressed in separate Cochrane reviews, but adverse effects (such as bleeding into the brain or gut) are sufficiently similar within the different disease groups that an independent review might address them together. Indeed, unless trials exist on combined populations, such a question would be difficult to address in any other way.


Similarly, there may be limited adverse effects data for an intervention in a sub-population, such as children. It may be worth analysing all available data for this sub-population (e.g. adverse effects of selective serotonin reuptake inhibitors in children), even if the trials were aimed at different disease conditions.


Authors of reviews of adverse effects alone must aim to provide adequate cross referencing (preferably through electronic links) to related reviews of intended effects of the intervention. If new safety concerns are identified when an efficacy review is updated, then the adverse effects review should be updated as soon as possible.