David Moher and colleagues introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses

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Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement

Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field,1,2 and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research,3 and some health care journals are moving in this direction.4 As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews.

Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in 4 leading medical journals in 1985 and 1986 and found that none met all 8 explicit scientific criteria, such as a quality assessment of included studies.5 In 1987, Sacks and colleagues6 evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in 6 domains. Reporting was generally poor; between 1 and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement.7

In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials.8 In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1).



Box 1

Conceptual issues in the evolution from QUOROM to PRISMA

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement.

Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice? 

Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis.

Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4

Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted?

A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …

/pdf/measuring-inconsistency-in-meta-analyses-4iysmttp08.pdf

Measuring inconsistency in meta-analyses

Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement

Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement [in Spanish]

Airways Disease Presenting as Restrictive Impairment: Response

Introduction Transplantation is a definitive treatment option for many people suffering from end-stage organ failure. Organ supply, however, far exceeds the supply. While recent studies suggest that improved management of deceased organ donors may increase transplant rates and allograft function, research to support best practices in donor management is sparse. The DONATE Pilot Observational Study aims to identify and to address logistical and regulatory complexities prior to embarking upon a national observational study that will improve the care of organ donors and lay the foundation for future clinical trials. Methods This 12 month prospective cohort study was conducted between September 2015 - April 2017 in the intensive care units (ICUs) of 8 Ontario and Quebec hospitals enrolled consecutively consented adult deceased donors [donation after neurological determination of death (DND) and donation after circulatory determination of death (DCD). The primary outcomes of this pilot study included the successful application of a waived research consent model, the time to complete the case report forms (CRF) and the completeness of transplant recipient data. Detailed data from various hospital sources and provincial organ donation organizations included death determination procedures, cardiopulmonary monitoring technologies, basic and advanced life sustaining therapy, general prophylactic interventions, organ donation specific therapies and clinical complications, defined a priori, from one day prior to donation consent up to the time of organ recovery. We also recorded specific limited data about the transplant recipients. Results In collaboration with ethicists, lawyers and privacy officers, all hospitals obtained authorization to implement this study with a waiver of research consent. The study, includes 180 consecutive deceased donors (58% DND; 42% DCD). The most common critical illness leading to organ donation was global anoxic brain injury (n = 37, 20.,6%). The mean time from donation consent to organ recovery was 2.39 days (SD = 0.72). Research coordinators estimated that prospective data completion required 5-7 hours per participant, but retrospective approaches required more time. With formal data sharing agreements, we obtained recipient data. Conclusion This pilot study identified and addressed some unique logistical and regulatory organ donation research challenges. The process provides a framework for addressing the same issues, and refining data collection, in the context of an upcoming national prospective cohort study. Clinical findings from the national cohort will inform the design of future trials in organ donor management. Canadian Critical Care Trials Group. Canadian National Transplant Research Program.

DONATE: A 8 centre pilot study

Source Citation Roberts I, Yates D, Sandercock P, et al. Effect of intravenous corticosteroids on death within 14 days in 10008 adults with clinically significant head injury (MRC CRASH trial): ran...

Methylprednisolone caused an increase in death after head injury.

Pseudoxanchoma elasticum (PXE) is an inherited disorder of
connective tissue, characterized by calcification and degeneration of elastin.
Clinical manifestations of PXE are protean, with skin, eyes and arteries being
most commonly involved. Although often a benign condition, gastrointestinal
hemorrhage is a potentially fatal complication. An unusual case of gastrointestinal
hemorrhage in a patient with PXE is described and the pathophysiology,
clinical presentation and complications of this rare condition are reviewed.

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Psudoxanthoma elasticum: An Unusual Case of Gastrointestinal Bleeding

Source Citation Levi M, Levy M, Williams MD, et al. Prophylactic heparin in patients with severe sepsis treated with drotrecogin alfa (activated). Am J Respir Crit Care Med. 2007;176:483-90. 17556722

Deborah J. Cook

Papers

Airways Disease Presenting as Restrictive Impairment: Response

DONATE: A 8 centre pilot study

Methylprednisolone caused an increase in death after head injury.

Psudoxanthoma elasticum: An Unusual Case of Gastrointestinal Bleeding

Heparin prophylaxis did not increase mortality and was beneficial in adults with sepsis receiving drotrecogin alfa