Inclusion of nonrandomized studies of interventions in systematic reviews of interventions: updated guidance from the Agency for Health Care Research and Quality Effective Health Care program

Abstract

Objectives

We developed guidance to inform decisions regarding the inclusion of nonrandomized studies of interventions (NRSIs) in systematic reviews (SRs) of the effects of interventions.

Study Design and Setting

The guidance workgroup comprised SR experts and used an informal consensus generation method.

Results

Instead of recommending NRSI inclusion only if randomized controlled trials (RCTs) are insufficient to address the SR key question, different topics may require different decisions regarding NRSI inclusion. We identified important considerations to inform such decisions from topic refinement through protocol development. During topic scoping and refinement, considerations were related to the clinical decisional dilemma, adequacy of RCTs to address the key questions, risk of bias in NRSIs, and the extent to which NRSIs are likely to complement RCTs. When NRSIs are included, during SR team formation, familiarity with topic-specific data sources and advanced analytic methods for NRSIs should be considered. During protocol development, the decision regarding NRSI inclusion or exclusion should be justified, and potential implications explained. When NRSIs are included, the protocol should describe the processes for synthesizing evidence from RCTs and NRSIs and determining the overall strength of evidence.

Conclusion

We identified specific considerations for decisions regarding NRSI inclusion in SRs and highlight the importance of flexibility and transparency.

Table 1Summary of considerations for deciding whether to include nonrandomized studies of interventions in systematic reviews of the effects of interventions

Systematic review step	Considerations
Topic scoping and refinement	Consider the following questions at a minimum when evaluating the potential utility of RCTs and NRSIs: 1. What are the decisional dilemmas and KQs being addressed, and how will the end-user(s) of the systematic review use the evidence to inform decision making? 2. Is it logical and likely for RCTs to have addressed the KQs adequately? 3. How serious is the risk of bias in NRSIs that address the KQs likely to be? 4. To what extent are NRSIs and RCTs likely to complement each other?
Systematic review team formation	When NRSIs are included: 5. Ensure that the systematic review team members are familiar with topic-specific data sources and advanced analytic methods for NRSIs.
Protocol development	The protocol should: 6. Specify study design methods or features eligible for the systematic review. 7. Explain whether and why NRSIs will be included or excluded. 8. Explain the potential implications of the decision to include or exclude NRSIs. 9. When NRSIs are included, describe the processes for synthesizing evidence from RCTs and NRSIs and determining overall strength of evidence.

Systematic review step

Considerations

Topic scoping and refinement

Consider the following questions at a minimum when evaluating the potential utility of RCTs and NRSIs:

1.
What are the decisional dilemmas and KQs being addressed, and how will the end-user(s) of the systematic review use the evidence to inform decision making?
2.
Is it logical and likely for RCTs to have addressed the KQs adequately?
3.
How serious is the risk of bias in NRSIs that address the KQs likely to be?
4.
To what extent are NRSIs and RCTs likely to complement each other?

Systematic review team formation

When NRSIs are included:

5.
Ensure that the systematic review team members are familiar with topic-specific data sources and advanced analytic methods for NRSIs.

Protocol development

The protocol should:

6.
Specify study design methods or features eligible for the systematic review.
7.
Explain whether and why NRSIs will be included or excluded.
8.
Explain the potential implications of the decision to include or exclude NRSIs.
9.
When NRSIs are included, describe the processes for synthesizing evidence from RCTs and NRSIs and determining overall strength of evidence.

LEGGI TUTTO https://www.jclinepi.com/article/S0895-4356(22)00217-7/fulltext?dgcid=raven_jbs_etoc_email#:~:text=DOI%3A-,https%3A//doi.org/10.1016/j.jclinepi.2022.08.015,-PlumX%20Metrics

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