Perils of systematic reviews
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* Jeremy Grimshaw

*   © 2005 CMA Media Inc. or its licensors

Ariella Lang and Nancy Edwards comment on a Cochrane systematic review of support for women and families after perinatal death.1 That review highlighted that although such support is now part of standard nursing and social practice in most of the developed world, there is little evidence to support or refute the perceived benefits of the intervention. The authors of the review also noted that this aspect of standard care raises practical issues for future randomized trials. Nevertheless, they concluded that “Methodologically rigorous trials are needed in order to assess whether it is worth spending additional resources on care provided by professionals with specialised skills in managing bereavement, in comparison to that available when good routine perinatal care is provided by normally skilled sensitive professionals.” Lang and Edwards have identified a number of studies that appear to demonstrate that women's and families' experiences of current standard practice are often unsatisfactory. I do not think that these 2 views are necessarily discordant. It is possible that although bereavement counselling is standard, women and families do not optimally benefit from such counselling. This would appear to support the claim of Chambers and Chan1 that further rigorous trials are needed.

I strongly disagree with the notion expressed by Lang and Edwards that systematic reviews with no or few rigorous studies are unhelpful. Such reviews point out the limitations of the current evidence base, define the future research agenda and identify the most critical elements for future randomized trials. For example, Chambers and Chan commented that “further trials should ensure that the range of outcome measures is clearly defined and is assessed by standard psychometric tools, as far as possible validated for the purpose, that data [are] numerically complete and appropriately presented and that adequate follow-up is possible.”

As described in my commentary,2 one unique element of Cochrane reviews is that readers are encouraged to send feedback; reviewers are required to respond to such feedback and update their reviews if appropriate. I would encourage Lang and Edwards to submit such feedback if my response has not adequately addressed their concerns.

## Footnotes

*   *Competing interests:* Jeremy Grimshaw is Director of the Canadian Cochrane Centre, Co-ordinating Editor of the Cochrane Effective Practice and Organisation of Care (EPOC) review group and author of several Cochrane reviews.

## References

1.  1. Chambers HM, Chan FY. Support for women/families after perinatal death [Cochrane review]. In: The Cochrane Library; Issue 2, 2004. Oxford: Update Software.
    
    

2.  2. Grimshaw J. So what has the Cochrane Collaboration ever done for us? A report card on the first 10 years [editorial]. CMAJ 2004;171(7):747-9.
    
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