Background: Systematic reviews should compare risks and harms to benefits to optimise their usefulness in supporting guideline development. As an example, prescription opioids have become the leading cause of injury deaths and considerable morbidity in the US because harms were not considered. Guideline recommendations and informed consent discussions will be hampered if there is lack of synthesised data to support risk vs. benefit discussions.

Objectives: 1) To review and compare extant systematic reviews’ consideration of the adverse personal and population effects of acute and chronic opioids compared to consideration of benefits.
2) To guide SR development so that SRs facilitate informed recommendation development, considering risks vs. benefits

Methods: We reviewed existing SRs in the Cochrane Library and several other SRs to determine the extent and methods of adverse effects review compared to review of benefits, and used the Cochrane Adverse Effects Review methodology as a standard.

Results: Most systematic reviews supporting pain treatment guidelines consider only some adverse effects (or none in some cases), some types of patients, and some classes of evidence, with little synthesis. Population effects are generally ignored. As a result, it is likely that some guidelines and physician surveys still advocate more widespread use of opioids for chronic non-cancer pain, particularly in the elderly, who are at higher risk. Opioids affect most organ systems, with risk related to dose, age, gender, co-morbidity, and concurrent use of multiple opioids and sedative/hypnotic and psychiatric medication. Review of observational studies is an important part of adverse effects review as an element of comprehensive systematic reviews, or as a companion document to effectiveness reviews. 

Conclusions: Systematic reviews should explicitly consider the many effects of opioid use on personal and public safety, quality of life, function and avoidable adverse health effects. Guideline developers, and all other stakeholders, need full information about benefits, risks, and adverse effects and risks to inform recommendation development and decision making.