Almost all articles on cancer prognostic markers report statistically significant results

Kyzas, Panayiotis; Denaxa-Kyza, Despina; Ioannidis, John P. A.

doi:10.1016/j.ejca.2007.08.030

Cited by 211 publications

(163 citation statements)

References 36 publications

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“…As reviewed elsewhere (Kyzas et al 2007), it is a common practice to highlight positive and statistically significant results in the abstract or conclusion sections of articles. Most studies included in the present review reported some positive findings.…”

Section: Consistency Of Methods Results and Reporting Across Studiesmentioning

confidence: 99%

Systematic review of the literature on triclosan and health outcomes in humans

Goodman

Naiman

LaKind

2017

Critical Reviews in Toxicology

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The ability of epidemiologic evidence to inform regulatory decisions is largely dependent on the coherence and quality of the published literature. This systematic review examines the quality and consistency of studies assessing health outcomes associated with exposure to triclosan (TCS), an antimicrobial chemical with a short physiologic half-life. We used elements of the Biomonitoring, Environmental Epidemiology, and Short-Lived Chemicals instrument to evaluate aspects of study quality. Each methodological domain -overall design, exposure assessment, and data analysis -was categorized according to three tiers where Tier 1 indicated the highest quality. We also examined consistency of methods, results and reporting as considerations for weight of evidence (WOE) assessment. Studies were considered sufficiently comparable if they addressed the same or similar research questions. Forty-two studies met the criteria for inclusion. Only one randomized cross-over clinical trial of TCS was assigned to Tier 1 for all three domains. Most other studies were assigned to Tier 3 for at least one domain. Although the available literature examined more than 100 different health endpoints and reported hundreds of different measures of association, few studies were considered comparable. For reported measures of association, most were not significantly different from the null; the few statistically significant results represented isolated findings without a discernable across-or within-study pattern. We conclude that the current body of epidemiologic literature does not allow a meaningful WOE assessment due to methodological limitations of individual studies and lack of inter-study consistency. On the other hand, methodologically stronger studies may be used to inform future research. ARTICLE HISTORY

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Section: Consistency Of Methods Results and Reporting Across Studiesmentioning

confidence: 99%

Systematic review of the literature on triclosan and health outcomes in humans

Goodman

Naiman

LaKind

2017

Critical Reviews in Toxicology

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“…There is ample evidence that prediction research often suffers from poor design and bias, and these may also have an impact on the results of the studies and on the models of disease outcomes based on these studies [4][5][6]. Although most prognostic studies published to date claim significant results [7,8], very few translate to clinically useful applications. Just as for observational epidemiological studies [9], poor reporting complicates the use of the specific study for research, clinical or public health purposes and hampers the synthesis of evidence across studies.…”

Section: Introductionmentioning

confidence: 99%

Strengthening the reporting of genetic risk prediction studies: the GRIPS statement

Janssens

Ioannidis

Duijn

et al. 2011

European Journal of Clinical Investigation

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“…293 Primary prognostic factor studies are often poorly designed, inappropriately analysed and poorly/selectively reported. [289][290][291][292][297][298][299][300][301][302][303][304] This leads to confusion about whether or not factors are genuinely prognostic, with the play of chance and selective reporting typically leading to overoptimism in the prognostic effect sizes seen in the literature.…”

Section: Recommendations For Future Researchmentioning

confidence: 99%

The prognostic utility of tests of platelet function for the detection of ‘aspirin resistance’ in patients with established cardiovascular or cerebrovascular disease: a systematic review and economic evaluation

Dretzke

Riley

Lordkipanidzé

et al. 2015

Health Technology Assessment

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BackgroundThe use of aspirin is well established for secondary prevention of cardiovascular disease. However, a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment. It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity. This report aims to investigate whether or not insufficient platelet function inhibition by aspirin (‘aspirin resistance‘), as defined using platelet function tests (PFTs), is linked to the occurrence of adverse clinical outcomes, and further, whether or not patients at risk of future adverse clinical events can be identified through PFTs.ObjectivesTo review systematically the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT designation of ‘aspirin resistance’ and the risk of adverse clinical outcome(s) in patients prescribed aspirin therapy. To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs.Data sourcesBibliographic databases (e.g. MEDLINE from inception and EMBASE from 1980), conference proceedings and ongoing trial registries up to April 2012.MethodsStandard systematic review methods were used for identifying clinical and cost studies. A risk-of-bias assessment tool was adapted from checklists for prognostic and diagnostic studies. (Un)adjusted odds and hazard ratios for the association between ‘aspirin resistance’, for different PFTs, and clinical outcomes are presented; however, heterogeneity between studies precluded pooling of results. A speculative economic model of a PFT and change of therapy strategy was developed.ResultsOne hundred and eight relevant studies using a variety of PFTs, 58 in patients on aspirin monotherapy, were analysed in detail. Results indicated that some PFTs may have some prognostic utility, i.e. a trend for more clinical events to be associated with groups classified as ‘aspirin resistant’. Methodological and clinical heterogeneity prevented a quantitative summary of prognostic effect. Study-level effect sizes were generally small and absolute outcome risk was not substantially different between ‘aspirin resistant’ and ‘aspirin sensitive’ designations.No studies on the cost-effectiveness of PFTs for ‘aspirin resistance’ were identified. Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification, the economic model found that a test–treat strategy was likely to be cost-effective. However, neither assumption is currently evidence based.LimitationsPoor or incomplete reporting of studies suggests a potentially large volume of inaccessible data. Analyses were confined to studies on patients prescribed aspirin as sole antiplatelet therapy at the time of PFT. Clinical and methodological heterogeneity across studies precluded meta-analysis. Given the lack of robust data the economic modelling was speculative.ConclusionsAlthough evidence indicates that some PFTs may have some prognostic value, methodological and clinical heterogeneity between studies and different approaches to analyses create confusion and inconsistency in prognostic results, and prevented a quantitative summary of their prognostic effect. Protocol-driven and adequately powered primary studies are needed, using standardised methods of measurements to evaluate the prognostic ability of each test in the same population(s), and ideally presenting individual patient data. For any PFT to inform individual risk prediction, it will likely need to be considered in combination with other prognostic factors, within a prognostic model.Study registrationThis study is registered as PROSPERO 2012:CRD42012002151.FundingThe National Institute for Health Research Health Technology Assessment programme.

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Almost all articles on cancer prognostic markers report statistically significant results

Cited by 211 publications

References 36 publications

Systematic review of the literature on triclosan and health outcomes in humans

Systematic review of the literature on triclosan and health outcomes in humans

Strengthening the reporting of genetic risk prediction studies: the GRIPS statement

The prognostic utility of tests of platelet function for the detection of ‘aspirin resistance’ in patients with established cardiovascular or cerebrovascular disease: a systematic review and economic evaluation

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