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.

Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews . Main outcome measure: Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. Results: In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. Conclusions: A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution. Key messages Systematic reviews of randomised trials are the best strategy for appraising evidence; however, the findings of some meta-analyses were later contradicted by large trials Funnel plots, plots of the trials9 effect estimates against sample size, are skewed and asymmetrical in the presence of publication bias and other biases Funnel plot asymmetry, measured by regression analysis, predicts discordance of results when meta-analyses are compared with single large trials Funnel plot asymmetry was found in 38% of meta-analyses published in leading general medicine journals and in 13% of reviews from the Cochrane Database of Systematic Reviews Critical examination of systematic reviews for publication and related biases should be considered a routine procedure

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Bias in meta-analysis detected by a simple, graphical test

Systematic review and meta-analysis

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

ing their paper (along with the peer reviews) referred to one of our family of ARCHIVES specialty journals for further consideration. We make every effort to ensure that articles published in JAMA continue to advance medical science, enhance clinical knowledge, and reflect the highest ethical standards of medical journalism. We sincerely appreciate the contributions of all JAMA peer reviewers and all JAMA authors in helping us achieve these important goals. Financial Disclosures: None reported.

https://jamanetwork.com/journals/jama/articlepdf/202484/jed60013.pdf

Lessons From and Cautions About Noninferiority and Equivalence Randomized Trials

BACKGROUND Somatostatin and its derivatives are often used for emergency treatment of bleeding oesophageal varices in patients with cirrhosis of the liver. The placebo controlled trials have shown varying results, however, and their power has been quite low. An updated systematic review of a previously published meta-analysis was therefore performed. OBJECTIVES To study whether somatostatin or analogues improve survival or reduce the number of blood transfusions in patients with suspected or verified acute or recently bleeding oesophageal varices. SEARCH STRATEGY MEDLINE and The Cochrane Library were searched in August 2001. Reference lists of articles and authors. SELECTION CRITERIA All randomised trials comparing somatostatin or analogues with placebo or no treatment in patients suspected of acute bleeding from oesophageal varices. DATA COLLECTION AND ANALYSIS The effect variables extracted were: mortality, number of blood transfusions, number with balloon tamponade, number with initial haemostasis and number with rebleeding. Intention to treat analyses were conducted; a random effects analysis was preferred if there was significant heterogeneity between the trials (P < 0.10). MAIN RESULTS The meta-analysis comprised 12 trials and 1452 patients. The active drugs did not reduce mortality significantly (relative risk 0.93, 95% confidence interval (CI) 0.75 to 1.14). The number of transfusions was less with drugs, the difference between experimental and control therapy was 1.0 units of blood products (95% CI 0.6 to 1.5). Number of patients failing initial haemostasis was also reduced (relative risk 0.68, 95% CI 0.50 to 0.92). There were no significant differences in use of balloon tamponade (relative risk 0.68, 95% CI 0.37 to 1.24), or in number of patients with rebleeding (relative risk 0.61, 95% CI 0.35 to 1.09). It should be noted, however, that the trials were heterogeneous with respect to the secondary outcomes. REVIEWER'S CONCLUSIONS The effect corresponded to one unit of blood saved per patient. It can be discussed whether this effect is worthwhile. The findings do not suggest a need for further placebo-controlled studies of somatostatin analogues in acute bleeding from oesophageal varices. On the other hand, the confidence interval for the effect on mortality was wide. Hence, a large placebo controlled trial is needed if one wishes to rule out the possibility that a worthwhile effect on mortality may have been overlooked.

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Somatostatin analogues for acute bleeding oesophageal varices.

Background to the debate: Ghostwriting occurs when someone makes substantial contributions to a manuscript without attribution or disclosure. It is considered bad publication practice in the medical sciences, and some argue it is scientific misconduct. At its extreme, medical ghostwriting involves pharmaceutical companies hiring professional writers to produce papers promoting their products but hiding those contributions and instead naming academic physicians or scientists as the authors. To improve transparency, many editors' associations and journals allow professional medical writers to contribute to the writing of papers without being listed as authors provided their role is acknowledged. This debate examines how best to tackle ghostwriting in the medical literature from the perspectives of a researcher, an editor, and the professional medical writer.

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What should be done to tackle ghostwriting in the medical literature

OBJECTIVE: To determine whether antifungal agents given prophylactically or empirically decrease morbidity and mortality in patients with cancer complicated by neutropenia. DESIGN: Meta-analysis of randomised trials of amphotericin B, various lipid soluble formulations of amphotericin B (for example, AmBisome), fluconazole, ketoconazole, miconazole, or itraconazole compared with placebo or no treatment. SETTING: Trials conducted anywhere in the world. SUBJECTS: Patients with cancer complicated by neutropenia. MAIN OUTCOME MEASURES: Mortality, invasive fungal infection (defined as positive blood culture, oesophageal candidiasis, or lung or deep tissue infection), and colonisation. RESULTS: 24 trials with 2758 randomised patients were reviewed; the total number of deaths was 434. Prophylactic or empirical treatment with antifungals as a group bad no effect on mortality (odds ratio 0.92; 95% confidence interval 0.74 to 1.14). Amphotericin B decreased mortality significantly (0.58; 0.37 to 0.93) but the studies were small and the difference in number of deaths was only 15. Antifungal treatment decreased the incidence of invasive fungal infection (0.47; 0.35 to 0.64) and fungal colonisation (0.45; 0.30 to 0.69). For every 73 patients treated (95% confidence interval to 48 to 158) one case of fungal invasion was prevented in surviving patients. CONCLUSIONS: There seems to be no survival benefit of antifungal agents given prophylactically or empirically to patients with cancer complicated by neutropenia. These agents should be restricted to patients with proved infection and those in randomised trials. A large, definitive placebo controlled trial of amphotericin B is needed.

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Meta-analysis of prophylactic or empirical antifungal treatment versus placebo or no treatment in patients with cancer complicated by neutropenia

Objective: To determine whether short term, oral low dose prednisolone (⩽15 mg daily) is superior to placebo and non-steroidal anti-inflammatory drugs in patients with rheumatoid arthritis. Design: Meta-analysis of randomised trials of oral corticosteroids compared with placebo or a non-steroidal anti-inflammatory drug. Setting: Trials conducted anywhere in the world. Subjects: Patients with rheumatoid arthritis. Main outcome measures: Joint tenderness, pain, and grip strength. Outcomes measured on different scales were combined by using the standardised effect size (difference in effect divided by SD of the measurements). Results: Ten studies were included in the meta-analysis. Prednisolone had a marked effect over placebo on joint tenderness (standardised effect size 1.31; 95% confidence interval 0.78 to 1.83), pain (1.75; 0.87 to 2.64), and grip strength (0.41; 0.13 to 0.69). Measured in the original units the differences were 12 (6 to 18) tender joints and 22 mm Hg (5 mm Hg to 40 mm Hg) for grip strength. Prednisolone also had a greater effect than non-steroidal anti-inflammatory drugs on joint tenderness (0.63; 0.11 to 1.16) and pain (1.25; 0.26 to 2.24), whereas the difference in grip strength was not significant (0.31; −0.02 to 0.64). Measured in the original units the differences were 9 (5 to 12) tender joints and 12 mm Hg (−6 mm Hg to 31 mm Hg). The risk of adverse effects during moderate and long term use seemed acceptable. Conclusion: Prednisolone in low doses (⩽15 mg daily) may be used intermittently in patients with rheumatoid arthritis, particularly if the disease cannot be controlled by other means. Key messages Prednisolone in low doses—that is, no more than 15 mg daily—is highly effective in patients with rheumatoid arthritis The risk of adverse effects is acceptable in short, moderate, or long term use Oral low dose prednisolone may be used intermittently in patients with rheumatoid arthritis, particularly if the disease cannot be controlled by other means Further short term placebo controlled trials to study the clinical effect of prednisolone or other oral corticosteroids are no longer necessary

https://www.bmj.com/content/bmj/316/7134/811.full.pdf

Peter C Gøtzsche

Papers

Lessons From and Cautions About Noninferiority and Equivalence Randomized Trials

Somatostatin analogues for acute bleeding oesophageal varices.

What should be done to tackle ghostwriting in the medical literature

Meta-analysis of prophylactic or empirical antifungal treatment versus placebo or no treatment in patients with cancer complicated by neutropenia

Meta-analysis of short term low dose prednisolone versus placebo and non-steroidal anti-inflammatory drugs in rheumatoid arthritis