PROSPERO - International prospective register of systematic reviews

PROSPERO is an international database of prospectively registered systematic reviews in health and social care. Key features from the review protocol are recorded and maintained as a permanent record in PROSPERO. This will provide a comprehensive listing of systematic reviews registered at inception, and enable comparison of reported review findings with what was planned in the protocol.

Substantial changes to the review questions or methods

• It can be difficult to decide whether an update to a review is in fact a new review. There is little published guidance on this. PROSPERO adopts a pragmatic approach. If changes to the review questions or methods are so substantial that they require major changes to the original protocol, this should be regarded as a new review rather than an update.

Examples that would constitute a new review

• addition of new treatment comparisons
  e.g. direct comparison of different drugs, when the old review included only comparisons of drug with placebo
• substantial changes to the population being studied
  e.g. adding adults to a review that was previously restricted to children
• exclusion criteria in the old review become inclusion criteria in the new review
• introduction of new analysis techniques
  e.g. a switch from aggregate data meta-analyses to individual participant meta-analyses.
  

If in doubt, a new record for a new review should be created. This will minimise the complexity of the editing to the original record in PROSPERO and make it easier for users to distinguish between the original review and the later version. Links between the new and original review can be added in the registration form.