Peter C Gøtzsche

Bio: Peter C Gøtzsche is an academic researcher from Cochrane Collaboration. The author has contributed to research in topics: Systematic review & Placebo. The author has an hindex of 90, co-authored 413 publications receiving 147009 citations. Previous affiliations of Peter C Gøtzsche include University of Copenhagen & Copenhagen University Hospital.

Why mammography screening has not lived up to expectations from the randomised trials

Abstract: We analysed the relation between tumour sizes and stages and the reported effects on breast cancer mortality with and without screening in trials and observational studies. The average tumour sizes in all the trials suggest only a 12% reduction in breast cancer mortality, which agrees with the 10% reported in the most reliable trials. Recent studies of tumour sizes and tumour stages show that screening has not lowered the rate of advanced cancers. In agreement with this, recent observational studies of breast cancer mortality have failed to find an effect of screening. In contrast, screening leads to serious harms in healthy women through overdiagnosis with subsequent overtreatment and false-positive mammograms. We suggest that the rationale for breast screening be urgently reassessed by policy-makers. The observed decline in breast cancer mortality in many countries seems to be caused by improved adjuvant therapy and breast cancer awareness, not screening. We also believe it is more important to reduce the incidence of cancer than to detect it ‘early.’ Avoiding getting screening mammograms reduces the risk of becoming a breast cancer patient by one-third.

Short-term low-dose corticosteroids vs placebo and nonsteroidal antiinflammatory drugs in rheumatoid arthritis.

Abstract: BACKGROUND The effect of low dose corticosteroids, equivalent to 15 mg prednisolone daily or less, in patients with rheumatoid arthritis has been questioned. We therefore performed a systematic review of trials which compared corticosteroids with placebo or non-steroidal, anti-inflammatory drugs. OBJECTIVES To determine whether short-term (i.e. as recorded within the first month of therapy), oral low-dose corticosteroids (corresponding to a maximum of 15 mg prednisolone daily) is superior to placebo and nonsteroidal, antiinflammatory drugs in patients with rheumatoid arthritis. SEARCH STRATEGY Medline Silverplatter, The Cochrane Controlled Trials Register, reference lists and a personal archive. SELECTION CRITERIA All randomised studies comparing an oral corticosteroid (not exceeding an equivalent of 15 mg prednisolone daily) with placebo or a nonsteroidal, antiinflammatory drug were eligible if they reported clinical outcomes within one month after start of therapy. DATA COLLECTION AND ANALYSIS Decisions on which trials to include were made independently by two observers based on the methods sections of the trials only. Standardised effect measures were used for the statistical analyses; the random effects model was used if P<0.10 for the test of heterogeneity. MAIN RESULTS Ten studies, involving 320 patients, 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 (standardised effect size 1.75, 0.87 to 2.64) and grip strength (standardised effect size 0.41, 0.13 to 0.69). Measured in the original units, the differences were 12 tender joints (6 to 18) and 22 mm Hg (5 to 40) for grip strength. Prednisolone also had a greater effect than nonsteroidal, antiinflammatory drugs on joint tenderness (standardised effect size 0.63, 0.11 to 1.16) and pain (standardised effect size 1.25, 0.26 to 2.24), whereas the difference in grip strength was not significant (standardised effect size 0.31, -0.02 to 0.64). Measured in the original units, the differences were 9 tender joints (5 to 12) and 12 mm Hg (-6 to 31). The risk of adverse effects, also during moderate- and long-term use, seemed acceptable. REVIEWER'S CONCLUSIONS Prednisolone in low doses (not exceeding 15 mg daily) may be used intermittently in patients with rheumatoid arthritis, particularly if the disease cannot be controlled by other means. Since prednisolone is highly effective, short-term placebo controlled trials studying the clinical effect of low-dose prednisolone or other oral corticosteroids are no longer necessary.

Overstating the Evidence for Lung Cancer Screening: The International Early Lung Cancer Action Program (I-ELCAP) Study

Abstract: Last year, the New England Journal of Medicine ran a lead article reporting that patients with lung cancer had a 10-year survival approaching 90% if detected by screening spiral computed tomography. The publication garnered considerable media attention, and some felt that its findings provided a persuasive case for the immediate initiation of lung cancer screening. We strongly disagree. In this article, we highlight 4 reasons why the publication does not make a persuasive case for screening: the study had no control group, it lacked an unbiased outcome measure, it did not consider what is already known about this topic from previous studies, and it did not address the harms of screening. We conclude with 2 fundamental principles that physicians should remember when thinking about screening: (1) survival is always prolonged by early detection, even when deaths are not delayed nor any lives saved, and (2) randomized trials are the only way to reliably determine whether screening does more good than harm.

Amphotericin B lipid soluble formulations versus amphotericin B in cancer patients with neutropenia

Abstract: Background Patients with cancer who are treated with chemotherapy or receive a bone marrow transplant have an increased risk of acquiring fungal infections. Such infections can be life-threatening. Antifungal drugs are therefore often given prophylactically to such patients, or when they have a fever. Objectives To compare the benefits and harms of lipid soluble formulations of amphotericin B with conventional amphotericin B in cancer patients with neutropenia. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) Issue 4, 2007, PubMed (November 2007) and the reference lists of articles. We searched the proceedings of the ICAAC (from 1990 to 2007), General Meeting of the ASM (from 1990 to 2007), and the European Congress of Clinical Microbiology and Infectious Diseases (1995 to 2007) and contacted researchers in the field. For the 2011 update we searched PubMed from 1966 to 18 July 2011 and the reference lists of articles. Selection criteria Randomised clinical trials comparing lipid soluble formulations of amphotericin B with conventional amphotericin B. Data collection and analysis The two review authors independently assessed trial eligibility, risk of bias and abstracted data. Main results We found 12 trials (1895 patients). Lipid-based amphotericin B was not more effective than conventional amphotericin B for mortality (relative risk (RR) 0.83, 95% confidence interval (CI) 0.62 to 1.12), but decreased invasive fungal infection (RR 0.65, 95% CI 0.44 to 0.97), nephrotoxicity, defined as a 100% increase in serum creatinine (RR 0.45, 95%CI 0.37 to 0.54), and number of dropouts (RR 0.78, 95%CI 0.62 to 0.97). For the drug used in most patients, AmBisome (3 trials, 1149 patients), there was no significant difference in mortality (RR 0.74, 95% CI 0.52 to 1.07) whereas it tended to be more effective than conventional amphotericin B for invasive fungal infection (RR 0.63, 95% CI 0.39 to 1.01, P = 0.053). AmBisome, amphotericin B in Intralipid (6 trials, 379 patients), amphotericin B colloidal dispersion (ABCD) (2 trials, 262 patients), and amphotericin B lipid complex (ABLC) (1 trial, 105 patients) all decreased the occurrence of nephrotoxicity, but conventional amphotericin B was rarely administered under optimal circumstances. For the 2011 update no additional trials were identified for inclusion. Authors' conclusions It is not clear whether there are any advantages of lipid-based formulations if conventional amphotericin B is administered under optimal circumstances and their high cost prohibits routine use in most settings. There is a need for large trials comparing lipid-based formulations of amphotericin B with conventional amphotericin B given in the same dose, with routine premedication for prevention of infusion-related toxicity, and with supplementation with fluid, potassium and magnesium for prevention of nephrotoxicity.

Content area experts as authors: helpful or harmful for systematic reviews and meta-analyses?

Abstract: Peter Gotzsche and John Ioannidis argue that it is not always sensible to include subject experts as authors of systematic reviews and meta-analyses

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

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

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

Abstract: 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

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

Abstract: 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