Archie Cochrane's challenge: can periodically updated reviews of all randomised controlled trials relevant to neurology and neurosurgery be produced?

When and how to update systematic reviews

BACKGROUND

Systematic reviews are most helpful if they are up-to-date. We did a systematic review of strategies and methods describing when and how to update systematic reviews.

OBJECTIVES

To identify, describe and assess strategies and methods addressing: 1) when to update systematic reviews and 2) how to update systematic reviews.

SEARCH STRATEGY

We searched MEDLINE (1966 to December 2005), PsycINFO, the Cochrane Methodology Register (Issue 1, 2006), and hand searched the 2005 Cochrane Colloquium proceedings.

SELECTION CRITERIA

We included methodology reports, updated systematic reviews, commentaries, editorials, or other short reports describing the development, use, or comparison of strategies and methods for determining the need for updating or updating systematic reviews in healthcare.

DATA COLLECTION AND ANALYSIS

We abstracted information from each included report using a 15-item questionnaire. The strategies and methods for updating systematic reviews were assessed and compared descriptively with respect to their usefulness, comprehensiveness, advantages, and disadvantages.

MAIN RESULTS

Four updating strategies, one technique, and two statistical methods were identified. Three strategies addressed steps for updating and one strategy presented a model for assessing the need to update. One technique discussed the use of the "entry date" field in bibliographic searching. Statistical methods were cumulative meta-analysis and predicting when meta-analyses are outdated.

AUTHORS' CONCLUSIONS

Little research has been conducted on when and how to update systematic reviews and the feasibility and efficiency of the identified approaches is uncertain. These shortcomings should be addressed in future research.

Synthesizing medical evidence: systematic reviews and metaanalyses

Systematic reviews and metaanalyses have become increasingly popular ways of summarizing, and sometimes extending, existing medical knowledge. In this review the authors summarize current methods of performing meta-analyses, including the following: formulating a research question; performing a structured literature search and a search for trials not published in the formal medical literature; summarizing and, where appropriate, combining results from several trials; and reporting and presenting results. Topics such as cumulative and Bayesian metaanalysis and metaregression are also addressed. References to textbooks, articles, and Internet resources are also provided. The goal is to assist readers who wish to perform their own metaanalysis or to interpret critically a published example.

Diagnostic reasoning in neurology

Studies examining physicians' clinical decisions have demonstrated considerable variation in decisions and practices and identified numerous challenges to effective, efficient, and accurate decision making. Although use of the decision aids and tools described in this article may help overcome many of these challenges, greater self-awareness of the diagnostic reasoning process and the factors influencing decisions also should help improve clinical decisions and reduce variation, irrespective of the use of these tools. Continued research into the determinants and nature of the diagnostic reasoning process will provide additional insights that can be used to develop and apply improved decision aids and corrective procedures to overcome persistent problems.

How good are volunteers at searching for published randomized controlled trials? The OSTR Collaborative Group. Ottawa Stroke Trials Registry

The Ottawa Stroke Trials Registry (OSTR) collects information on all randomized controlled trials (RCTs), in all languages, in which the primary focus is stroke. Published trials are added to the registry database once they have been identified by volunteers hand searching journals. We undertook this study to assess volunteer sensitivity, specificity, positive and negative predictive values, accuracy and reliability in identifying RCTs. Three volunteers participated in this study. The complete contents of five years of one journal were searched (n = 240) as were ten research reports from five journals. Volunteer sensitivity, specificity, positive and negative predictive values, and accuracy was 89.5%, 100%, 100%, 99.1%, and 99% respectively. Inter volunteer reliability was 0.87. Searching the published literature to identify RCTs is an enormous task. These results indicate that volunteers, with minimal training, can effectively contribute to this endeavour.

The Cochrane Collaboration Stroke Review Group

Background There is a pressing need to identify which interventions are definitely effective in the prevention of stroke and in the treatment and rehabilitation of stroke patients, which interventions are definitely ineffective, and which interventions require further research. This information is most reliably obtained from reviewing all the available evidence from randomized controlled trials in a systematic way.

Summary of Comment There have been many (at least 800) randomized controlled trials relevant to stroke. It would be difficult for any one individual to keep track of all these trials, and therefore most clinicians, therapists, and researchers are dependent, to some degree, on reviews of this literature. However, most current reviews are unsystematic and tend to be either incomplete or biased, so that their recommendations can be seriously flawed. Until now there has been no attempt to systematically identify all randomized controlled trials relevant to stroke (including subarachnoid hemorrhage), to review the data they contain, and to keep these reviews up-to-date in the light of new evidence. The Stroke Review Group has now been established within the Cochrane Collaboration to try to perform these tasks. There are presently 40 collaborators from 13 countries working on approximately 25 reviews.

Conclusions Identifying and reviewing all randomized controlled trials relevant to stroke should bring important benefits to patients and all those involved in purchasing or providing care for patients with stroke. The Cochrane Collaboration Stroke Review Group has started this process and would welcome help from anyone interested in collaborating in this enormous task.