Primary study authors of significant studies are more likely to believe that a strong association exists in a heterogeneous meta-analysis compared with methodologists

A framework is proposed for defining, categorizing, and assessing conflicts of interest in health research

OBJECTIVE

We propose an operational definition of conflicts of interest (COI), a framework for categorizing interests, and an approach to assessing whether an interest qualifies as a COI.

STUDY DESIGN AND SETTING

We reviewed the literature and conducted methodological studies to inform the development of a draft framework for classifying interests.

RESULTS

We developed the following operational definition: "a conflict of interest exists when a past, current, or expected interest creates a significant risk of inappropriately influencing an individual's judgment, decision, or action when carrying out a specific duty". Interest refers to a benefit (e.g., money received from industry) or to an attribute of the individual (e.g., having specific religious beliefs). The proposed framework includes seven types of interests relating to individuals (direct financial benefit, benefit through professional status, intellectual, and personal) or their institution (direct financial benefit to the institution, benefit through increasing services provided by the institution, and nonfinancial). When assessing whether an interest qualifies as a COI, one could consider its relevance, nature (e.g., cash vs. educational support), magnitude, and recency.

CONCLUSION

The proposed operational definition and categorization framework may help journals, guideline organizations, professional societies, and healthcare institutions enhance transparency in health research.

Psychologists update their beliefs about effect sizes after replication studies

Self-correction-a key feature distinguishing science from pseudoscience-requires that scientists update their beliefs in light of new evidence. However, people are often reluctant to change their beliefs. We examined belief updating in action by tracking research psychologists' beliefs in psychological effects before and after the completion of four large-scale replication projects. We found that psychologists did update their beliefs; they updated as much as they predicted they would, but not as much as our Bayesian model suggests they should if they trust the results. We found no evidence that psychologists became more critical of replications when it would have preserved their pre-existing beliefs. We also found no evidence that personal investment or lack of expertise discouraged belief updating, but people higher on intellectual humility updated their beliefs slightly more. Overall, our results suggest that replication studies can contribute to self-correction within psychology, but psychologists may underweight their evidentiary value.

School-based interventions to prevent anxiety, depression and conduct disorder in children and young people: a systematic review and network meta-analysis

Background

Schools in the UK increasingly have to respond to anxiety, depression and conduct disorder as key causes of morbidity in children and young people.

Objective

The objective was to assess the comparative effectiveness of educational setting-based interventions for the prevention of anxiety, depression and conduct disorder in children and young people.

Design

This study comprised a systematic review, a network meta-analysis and an economic evaluation.

Data sources

The databases MEDLINE, EMBASE™ (Elsevier, Amsterdam, the Netherlands), PsycInfo® (American Psychological Association, Washington, DC, USA) and Cochrane Central Register of Controlled Trials (CENTRAL) were searched to 4 April 2018, and the NHS Economic Evaluation Database (NHS EED) was searched on 22 May 2019 for economic evaluations. No language or date filters were applied.

Main outcomes

The main outcomes were post-intervention self-reported anxiety, depression or conduct disorder symptoms.

Review methods

Randomised/quasi-randomised trials of universal or targeted interventions for the prevention of anxiety, depression or conduct disorder in children and young people aged 4–18 years were included. Screening was conducted independently by two reviewers. Data extraction was conducted by one reviewer and checked by a second. Intervention- and component-level network meta-analyses were conducted in OpenBUGS. A review of the economic literature and a cost–consequence analysis were conducted.

Results

A total of 142 studies were included in the review, and 109 contributed to the network meta-analysis. Of the 109 studies, 57 were rated as having an unclear risk of bias for random sequence generation and allocation concealment. Heterogeneity was moderate. In universal secondary school settings, mindfulness/relaxation interventions [standardised mean difference (SMD) –0.65, 95% credible interval (CrI) –1.14 to –0.19] and cognitive–behavioural interventions (SMD –0.15, 95% CrI –0.34 to 0.04) may be effective for anxiety. Cognitive–behavioural interventions incorporating a psychoeducation component may be effective (SMD –0.30, 95% CrI –0.59 to –0.01) at preventing anxiety immediately post intervention. There was evidence that exercise was effective in preventing anxiety in targeted secondary school settings (SMD –0.47, 95% CrI –0.86 to –0.09). There was weak evidence that cognitive–behavioural interventions may prevent anxiety in universal (SMD –0.07, 95% CrI –0.23 to 0.05) and targeted (SMD –0.38, 95% CrI –0.84 to 0.07) primary school settings. There was weak evidence that cognitive–behavioural (SMD –0.04, 95% CrI –0.16 to 0.07) and cognitive–behavioural + interpersonal therapy (SMD –0.18, 95% CrI –0.46 to 0.08) may be effective in preventing depression in universal secondary school settings. Third-wave (SMD –0.35, 95% CrI –0.70 to 0.00) and cognitive–behavioural interventions (SMD –0.11, 95% CrI –0.28 to 0.05) incorporating a psychoeducation component may be effective at preventing depression immediately post intervention. There was no evidence of intervention effectiveness in targeted secondary, targeted primary or universal primary school settings post intervention. The results for university settings were unreliable because of inconsistency in the network meta-analysis. A narrative summary was reported for five conduct disorder prevention studies, all in primary school settings. None reported the primary outcome at the primary post-intervention time point. The economic evidence review reported heterogeneous findings from six studies. Taking the perspective of a single school budget and based on cognitive–behavioural therapy intervention costs in universal secondary school settings, the cost–consequence analysis estimated an intervention cost of £43 per student.

Limitations

The emphasis on disorder-specific prevention excluded broader mental health interventions and restricted the number of eligible conduct disorder prevention studies. Restricting the study to interventions delivered in the educational setting may have limited the number of eligible university-level interventions.

Conclusions

There was weak evidence of the effectiveness of school-based, disorder-specific prevention interventions, although effects were modest and the evidence not robust. Cognitive–behavioural therapy-based interventions may be more effective if they include a psychoeducation component.

Future work

Future trials for prevention of anxiety and depression should evaluate cognitive–behavioural interventions with and without a psychoeducation component, and include mindfulness/relaxation or exercise comparators, with sufficient follow-up. Cost implications must be adequately measured.

Study registration

This study is registered as PROSPERO CRD42016048184.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 9, No. 8. See the NIHR Journals Library website for further project information.

Drivers of the opioid crisis: An appraisal of financial conflicts of interest in clinical practice guideline panels at the peak of opioid prescribing

Background

Starting in the late 1990s, the pharmaceutical industry sought to increase prescribing of opioids for chronic non-cancer pain. Influencing the content of clinical practice guidelines may have been one strategy industry employed. In this study we assessed potential risk of bias from financial conflicts of interest with the pharmaceutical industry in guidelines for opioid prescribing for chronic non-cancer pain published between 2007 and 2013, the peak of opioid prescribing.

Methods

We used the Guideline Panel Review (GPR) to appraise the guidelines included in the 2014 systematic review and critical appraisal by Nuckols et al. These were English language opioid prescribing guidelines for adults with chronic non-cancer pain published between July 2007 and July 2013, the peak of opioid prescribing. The GPR assigns red flags to items known to introduce potential bias from financial conflicts of interest. We operationalized the GPR by creating specific definitions for each red flag. Two reviewers independently evaluated each guideline. Disagreements were resolved with discussion. We also compared our score to the critical appraisal scores for overall quality from the study by Nuckols et al.

Results

We appraised 13 guidelines, which received 43 red flags in total. Guidelines had 3.3 red flags on average (out of a possible seven) with range from one to six. Four guidelines had missing information, so red flags may be higher than reported. The guidelines with the highest and second highest scores for overall quality in the 2014 critical appraisal by Nuckols et al. had five and three red flags, respectively.

Conclusion

Our findings reveal that the guidelines for opioid prescribing chronic non-cancer pain from 2007 to 2013 were at risk of bias because of pervasive conflicts of interest with the pharmaceutical industry and a paucity of mechanisms to address bias. Even highly-rated guidelines examined in a 2014 systematic review and critical appraisal had many red flags.

Relationship Between Declarations of Conflict of Interests and Reporting Positive Outcomes in Iranian Dental Journals

Conflict of interests is a situation when someone is in need of other people's trust on one the hand and has personal or general interests on the other hand, resulting in conflict with the given responsibility. In this research work, an attempt was made to find the relation between declarations of conflict of interests and reporting positive outcomes in the dental journals in Iran (2000-2016). In this analytical/cross-sectional study, first Health and Biomedical Information was searched and all the Persian and English dental journals published in Iran were collected. Then, all the papers published in the journals from December 2000 to December 2016 were collected and categorized in terms of the year of publication, author or authors' affiliations, Persian and English journal, type of the substance or the drug used (including the manufacturing company), declarations of conflict of interests and the positive or negative conclusion of the report. Data were analyzed with the Fisher's exact test and Chi squared test, using the program SPSS 18. In numerical analysis, the significance was set at P < 0.05. Seventeen dental journals in Persian and English were analyzed: 10 in English and 7 in Persian. Reviewing these studies showed that of 1021 articles in Persian, in 128 cases there was no mention of a declaration of conflict of interests and in 11 cases, the COI had been stated. In addition, from 1220 articles in English, in 825 cases there was no mention of declarations of conflict of interests and in 45 cases, the declarations of COI had been mentioned. There was no significant relation between the COI and 'no' COI and the reporting of positive outcomes in papers in Iranian dental journals in terms of the journal type, year of publication and the journals' guarantee form (P = 0.25, P = 0.41 and P = 0.09). A total of 83% of studies with declarations of COI had one positive outcome, with a significant relationship in this field; however, in 73% of studies with no COI, there was one positive outcome, too. In general, the society expects that doctors would not consider any incentives except the health of the patients in the efforts made by them. The severity of the consequences of COI is of higher value when the patients' health is endangered due to it. In addition, COI might change the attitude and approach of other doctors and peers.

Dairy Products: Is There an Impact on Promotion of Prostate Cancer? A Review of the Literature

This review of the literature aims to study potential associations between high consumption of milk and/or dairy products and prostate cancer (PC). Literature is scarce, yet there is a direct relationship between mTORC1 activation and PC; several ingredients in milk/dairy products, when in high concentrations, increase signaling of the mTORC1 pathway. However, there are no studies showing an unequivocal relationship between milk products PC initiation and/or progression. Three different reviews were conducted with articles published in the last 5 years: (M1) PC and intake of dairy products, taking into account the possible mTORC1signaling mechanism; (M2) Intake of milk products and incidence/promotion of PC; (M3) mTORC1 activation signaling pathway, levels of IGF-1 and PC; (M4) mTORC pathway and dairy products. Of the 32 reviews identified, only 21 met the inclusion criteria and were analyzed. There is little scientific evidence that directly link the three factors: incidence/promotion of PC, intake of dairy products and PC, and PC and increased mTORC1 signaling. Persistent hyper-activation of mTORC1 is associated with PC promotion. The activity of exosomal mRNA in cellular communication may lead to different impacts of different types of milk and whether or not mammalian milks will have their own characteristics within each species. Based on this review of the literature, it is possible to establish a relationship between the consumption of milk products and the progression of PC; we also found a possible association with PC initiation, hence it is likely that the intake of dairy products should be reduced or minimized in mens' diet.

Reporting of Financial and Non-financial Conflicts of Interest in Systematic Reviews on Health Policy and Systems Research: A Cross Sectional Survey

Background: Systematic reviews are increasingly used to inform health policy-making. The conflicts of interest (COI) of the authors of systematic reviews may bias their results and influence their conclusions. This may in turn lead to misguided public policies and systems level decisions. In order to mitigate the adverse impact of COI, scientific journals require authors to disclose their COIs. The objective of this study was to assess the frequency and different types of COI that authors of systematic reviews on health policy and systems research (HSPR) report.

Methods: We conducted a cross sectional survey. We searched the Health Systems Evidence (HSE) database of McMaster Health Forum for systematic reviews published in 2015. We extracted information regarding the characteristics of the systematic reviews and the associated COI disclosures. We conducted descriptive analyses.

Results: Eighty percent of systematic reviews included authors’ COI disclosures. Of the 160 systematic reviews that included COI disclosures, 15% had at least one author reporting at least one type of COI. The two most frequently reported types of COI were individual financial COI and individual scholarly COI (11% and 4% respectively). Institutional COIs were less commonly reported than individual COIs (3% and 15% respectively) and non-financial COIs were less commonly reported than financial COIs (6% and 14% respectively). Only one systematic review reported the COI disclosure by editors, and none reported disclosure by peer reviewers. All COI disclosures were in the form of a narrative statement in the main document and none in an online document.

Conclusion: A fifth of systematic reviews in HPSR do not include a COI disclosure statement, highlighting the need for journals to strengthen and/or better implement their COI disclosure policies. While only 15% of identified disclosure statements report any COI, it is not clear whether this indicates a low frequency of COI versus an underreporting of COI, or both.

Overdiagnosis or not? 2017 ACC/AHA high blood pressure clinical practice guideline: Consequences of intellectual conflict of interest

American Heart Association/the American College of Cardiology and nine other professional organizations have issued a new hypertension clinical practice guideline (CPG) on November 2017, which has lowered the hypertension threshold to 130/80 mmHg. American Academy of Family Medicine has decided to not endorse this new CPG for various reasons including flaws in CPG development process and a limited additional benefit for lower treatment targets. The major concern was intellectual conflict of interest (COI). Substantial weight was given to SPRINT trial, which provided the basis for the recommended change in blood pressure targets. It is a serious intellectual COI that the Chair of the SPRINT trial steering committee was commissioned as chair of the guideline panel. The new threshold would lead to 46 percent of the U.S. adult population being categorized as having hypertension, while using the previous threshold that figure would be 32 percent. Should we call this change as overdiagnosis?

Including values in evidence-based policy making for breast screening: An empirically grounded tool to assist expert decision makers

Values are an important part of evidence-based decision making for health policy: they guide the type of evidence that is collected, how it is interpreted, and how important the conclusions are considered to be. Experts in breast screening (including clinicians, researchers, consumer advocates and senior administrators) hold differing values in relation to what is important in breast screening policy and practice, and committees may find it difficult to incorporate the complexity and variety of values into policy decisions. The decision making tool provided here is intended to assist with this process. The tool is modified from more general frameworks that are intended to assist with ethical decision making in public health, and informed by data drawn from previous empirical studies on values amongst Australian breast screening experts. It provides a structured format for breast screening committees to consider and discuss the values of themselves and others, suggests relevant topics for further inquiry and highlights areas of need for future research into the values of the public. It enables committees to publicly explain and justify their decisions with reference to values, improving transparency and accountability. It is intended to act alongside practices that seek to accommodate the values of individual women in the informed decision making process for personal decision making about participation in breast screening.

A manifesto for reproducible science

Improving the reliability and efficiency of scientific research will increase the credibility of the published scientific literature and accelerate discovery. Here we argue for the adoption of measures to optimize key elements of the scientific process: methods, reporting and dissemination, reproducibility, evaluation and incentives. There is some evidence from both simulations and empirical studies supporting the likely effectiveness of these measures, but their broad adoption by researchers, institutions, funders and journals will require iterative evaluation and improvement. We discuss the goals of these measures, and how they can be implemented, in the hope that this will facilitate action toward improving the transparency, reproducibility and efficiency of scientific research.

Triangulating meta-analyses: the example of the serotonin transporter gene, stressful life events and major depression

Background

Meta-analysis is intended as a tool for the objective synthesis of evidence across a literature, in order to obtain the best evidence as to whether or not an association or effect is robust. However, as the use of meta-analysis has proliferated it has become increasingly clear that the results of a meta-analysis can be critically sensitive to methodological and analytical choices, so that different meta-analyses on the same topic can arrive at quite different conclusions.

Results

We demonstrate the variability in results of different meta-analyses on the same topic, using the example of the literature on the putative moderating effect of 5-HTTLPR genotype on the association between stressful life events and major depression. We also extend on previous work by including a P-curve analysis of studies from this literature, drawn from a previous meta-analysis, in an attempt to resolve the discrepant conclusions arrived at by previous meta-analyses.

Conclusions

We highlight the divergent conclusions that can be reached when different methodological and analytical choices are taken, and argue that triangulating evidence using multiple evidence synthesis methods is preferable where possible, and that every effort should be made for meta-analyses to be as unbiased as possible (e.g., conducted by methodologists or as part of an adversarial collaboration between authors from opposing camps).

Electronic supplementary material

The online version of this article (doi:10.1186/s40359-016-0129-0) contains supplementary material, which is available to authorized users.

Requirements of Clinical Journals for Authors' Disclosure of Financial and Non-Financial Conflicts of Interest: A Cross Sectional Study

IMPORTANCE

It is unclear how medical journals address authors' financial and non-financial conflict of interest (COI).

OBJECTIVE

To assess the policies of clinical journals for disclosure of financial and non-financial COI.

METHODS

Cross sectional study that included both review of public documents as well as a simulation of a manuscript submission for the National Library of Medicine's "core clinical journals". The study did not involve human subjects. Investigators who abstracted the data, reviewed "instructions for authors" on the journal website and, in order to reflect the actual implementation of the COI disclosure policy, simulated the submission of a manuscript. Two individuals working in duplicate and independently to abstract information using a standardized data abstraction form, resolved disagreements by discussion or with the help of a third person.

RESULTS

All but one of 117 core clinical journals had a COI policy. All journals required disclosure of financial COI pertaining to the authors and a minority (35%) asked for financial COI disclosure pertaining to the family members or authors' institution (29%). Over half required the disclosure of at least one form of non-financial COI (57%), out of which only two (3%) specifically referred to intellectual COI. Small minorities of journals (17% and 24% respectively) described a potential impact of disclosed COI and of non-disclosure of COI on the editorial process.

CONCLUSION

While financial COI disclosure was well defined by the majority of the journals, many did not have clear policies on disclosure of non-financial COI, disclosure of financial COI of family members and institutions of the authors, and effect of disclosed COI or non-disclosure of COI on editorial policies.

Multivariate piecewise exponential survival modeling

In this article, we develop a piecewise Poisson regression method to analyze survival data from complex sample surveys involving cluster-correlated, differential selection probabilities, and longitudinal responses, to conveniently draw inference on absolute risks in time intervals that are prespecified by investigators. Extensive simulations evaluate the developed methods with extensions to multiple covariates under various complex sample designs, including stratified sampling, sampling with selection probability proportional to a measure of size (PPS), and a multi-stage cluster sampling. We applied our methods to a study of mortality in men diagnosed with prostate cancer in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial to investigate whether a biomarker available from biospecimens collected near time of diagnosis stratifies subsequent risk of death. Poisson regression coefficients and absolute risks of mortality (and the corresponding 95% confidence intervals) for prespecified age intervals by biomarker levels are estimated. We conclude with a brief discussion of the motivation, methods, and findings of the study.

Application of credibility ceilings probes the robustness of meta-analyses of biomarkers and cancer risk

OBJECTIVES

Meta-analyses of biomarkers often present spurious significant results and large effects. We applied sensitivity analyses with the use of credibility ceilings to assess whether and how the results of meta-analyses of biomarkers and cancer risk would change.

STUDY DESIGN AND SETTING

We evaluated 98 meta-analyses, 43 (44%) of which had nominally statistically significant results. We assumed that any single study cannot give more than a maximum certainty 100 - c% (c, credibility ceiling) that the effect estimate [odds ratio (OR)] exceeds 1 (null) or 1.2.

RESULTS

Nominal statistical significance was maintained for 21 (21%) meta-analyses, for c = 10% and OR >1, and these proportions changed to 7%, 3%, and 6% with ceilings of 20%, 30%, and 40%, respectively. For ceilings for OR >1.2, the respective proportions were 37%, 21%, 7%, and 3%. Seven meta-analyses on infectious agents retained statistical significance even with a high ceiling of c = 20% for OR >1.00. Meta-analyses without other hints of bias (large between-study heterogeneity, small-study effects, excess significance) were more likely to retain statistical significance than those that had such hints of bias.

CONCLUSION

Credibility ceilings may be helpful in meta-analyses of biomarkers to understand the robustness of the results to different levels of uncertainty.

Critical assessment of high-circulation print newspaper coverage of the Institute of Medicine report Dietary Reference Intakes for Calcium and Vitamin D

OBJECTIVE

To evaluate high-circulation US and Canadian newspaper coverage of the Institute of Medicine (IOM) report Dietary Reference Intakes for Calcium and Vitamin D and assess pre-report and post-report reporter-specific vitamin D-related coverage.

DESIGN

Two independent reviewers analysed the newspaper articles. The key report findings cited, proportion of sentences describing the IOM report and proportion of sentences describing critical viewpoints on the report were calculated. The content of articles written by reporters with a history of pre-report vitamin D-related articles was compared with that of articles written by reporters without such a history.

SETTING

Factiva and LexisNexis searches of the top thirty US and three English-language Canadian print newspapers, by circulation.

SUBJECTS

Articles on the IOM report published from 30 November to 21 December 2010 and previous vitamin D-related articles written by the same reporters.

RESULTS

Only ten articles met inclusion/exclusion criteria. Articles inconsistently cited the key findings in the IOM report. Reporters with a history of pre-report articles highlighting the benefits of vitamin D dedicated a greater proportion of sentences to viewpoints critical of the IOM report (P < 0·01). There was no significant difference between pre-report publication history and proportion of sentences focused on the IOM report. A borderline-significant difference (P = 0·058) was observed between pre-report articles highlighting the benefits of vitamin D and the absence of reference to potential risks of vitamin D overconsumption.

CONCLUSION

Our findings suggest that newspaper articles did not consistently or comprehensively report the IOM recommendations and that pre-report publication history of reporters was related to post-report article content.

Use and applications of systematic reviews in public health nutrition

Decisions related to a spectrum of nutrition-related public health and clinical concerns must consider many factors and are best informed by evaluating the totality and quality of the evidence. Systematic review (SR) is a structured process to evaluate, compare, and synthesize relevant evidence for the SR-specific question(s). Applications of SR are exemplified here through the discussion of four case studies: research agendas, nutrient reference intakes, dietary guidance, and practice guidelines. Concerns that SR cannot be effectively applied to nutrition evidence because of the lack of an unexposed comparator and the complex homeostasis in nutrition are discussed. Central to understanding the applicability of SR is its flexibility in defining key inclusion criteria and rigorous elements as appropriate for the SR-specific question(s). Through the reduction of bias and random error by explicit, reproducible, comprehensive, and rigorous examination of all of the evidence, SR informs the scientific judgment needed for sound evidence-based public health nutrition.

Overlapping meta-analyses on the same topic: survey of published studies

OBJECTIVE

To assess how common it is to have multiple overlapping meta-analyses of randomized trials published on the same topic.

DESIGN

Survey of published meta-analyses.

DATA SOURCES

PubMed.

STUDY SELECTION AND METHODS

Meta-analyses published in 2010 were identified, and 5% of them were randomly selected. We further selected those that included randomized trials and examined effectiveness of any medical intervention. For eligible meta-analyses, we searched for other meta-analyses on the same topic (covering the same comparisons, indications/settings, and outcomes or overlapping subsets of them) published until February 2013.

RESULTS

Of 73 eligible meta-analyses published in 2010, 49 (67%) had at least one other overlapping meta-analysis (median two meta-analyses per topic, interquartile range 1-4, maximum 13). In 17 topics at least one author was involved in at least two of the overlapping meta-analyses. No characteristics of the index meta-analyses were associated with the potential for overlapping meta-analyses. Among pairs of overlapping meta-analyses in 20 randomly selected topics, 13 of the more recent meta-analyses did not include any additional outcomes. In three of the four topics with eight or more published meta-analyses, many meta-analyses examined only a subset of the eligible interventions or indications/settings covered by the index meta-analysis. Conversely, for statins in the prevention of atrial fibrillation after cardiac surgery, 11 meta-analyses were published with similar eligibility criteria for interventions and setting: there was still variability on which studies were included, but the results were always similar or even identical across meta-analyses.

CONCLUSIONS

While some independent replication of meta-analyses by different teams is possibly useful, the overall picture suggests that there is a waste of efforts with many topics covered by multiple overlapping meta-analyses.

Underreporting of conflicts of interest in clinical practice guidelines: cross sectional study

Background

Conflicts of interest affect recommendations in clinical guidelines and disclosure of such conflicts is important. However, not all conflicts of interest are disclosed. Using a public available disclosure list we determined the prevalence and underreporting of conflicts of interest among authors of clinical guidelines on drug treatments.

Methods

We included up to five guidelines published from July 2010 to March 2012 from each Danish clinical specialty society. Using the disclosure list of the Danish Health and Medicines Authority, we identified author conflicts of interest and compared them with the disclosures in the guidelines. For each guideline we extracted methodological characteristics of guideline development.

Results

Forty-five guidelines from 14 specialty societies were included. Of 254 authors, 135 (53%) had conflicts of interest, corresponding to 43 of the 45 guidelines (96%) having one or more authors with a conflict of interest. Only one of the 45 guidelines (2%) disclosed author conflicts of interest. The most common type of conflict of interest (83 of the 135) was being a consultant, an advisory board member or a company employee. Only 10 guidelines (22%) described the methods used for guideline development, 27 (60%) used references in the text and 11 (24%) graded the types of evidence.

Conclusions

Conflicts of interest were common, but disclosures were very rare. Most guidelines did not describe how they were developed and many did not describe the evidence behind specific recommendations. Publicly available disclosure lists may assist guideline issuing bodies in ensuring that all conflicts are disclosed.

Genetic polymorphisms associated with retinal vein occlusion: a Greek case-control study and meta-analysis

BACKGROUND

The genetic background of retinal vein occlusion (RVO) remains unclear. In the current study, we aimed to replicate polymorphisms related to thrombophilia/hypofibrinolysis in a Greek population and also systematically summarize current evidence available on the topic.

MATERIALS AND METHODS

A total of 48 RVO patients and 53 controls were genotyped for factor V H1299R and V Leiden, β-fibrinogen G455A, PAI-1 4G/5G, ACE I/D, HPA1, prothrombin G20210A, factor XIII Val34Leu, MTHFR A1298C and C677T polymorphisms. We examined the association between RVO and the above polymorphisms under a per-allele genetic model in a Greek unrelated case/control population. Additionally, searching PubMed up to January 2012, we identified existing evidence on these polymorphisms and performed meta-analyses.

RESULTS

A total of three polymorphisms had nominally significant associations with RVO. These associations pertained to ACE D allele (odds ratio, OR, 2.08 [95% CI, 1.12-3.85], p = 0.02); factor XIII 34Leu allele (OR = 0.41 [95% CI, 0.18-0.95], p = 0.037] and MTHFR 677T variant (OR = 2.20 [95% CI 1.10-4.40], p = 0.026). We performed a meta-analysis on the associations between RVO and PAI-1 (n = 5), factor V Leiden (n = 21), MTHFR C677T (n = 19) and prothrombin G20210A (n = 21). We observed nominally significant associations only for PAI-1 (OR = 1.27 [95% CI, 1.02-1.60, p = 0.036]) (I(2) = 44.7%), and factor V Leiden (OR = 1.40 [95% CI, 1.07-1.84, p = 0.015]) (I(2) = 3.6%) using random effects model.

CONCLUSIONS

Our results suggest that there may be an association between increased risk for RVO and ACE I/D, MTHFR C677T, PAI-1 4G/5G and factor V Leiden polymorphisms, whereas the Val34Leu variant may exert a protective effect.

The implications of biomarker evidence for systematic reviews

BACKGROUND

In Evidence-Based Medicine, clinical practice guidelines and systematic reviews are crucial devices for medical practitioners in making clinical decision. Clinical practice guidelines are systematically developed statements to support health care decisions for specific circumstances whereas systematic reviews are summaries of evidence on clearly formulated clinical questions. Biomarkers are biological measurements (primarily molecular) that are used to diagnose, predict treatment outcomes and prognosticate disease and are increasingly used in randomized controlled trials (RCT).

METHODS

We search PubMed for systematic reviews, RCTs, case reports and non-systematic reviews with and without mentions of biomarkers between years 1990-2011. We compared the frequency and growth rate of biomarkers and non-biomarkers publications. We also compared the growth of the proportion of biomarker-based RCTs with the growth of the proportion of biomarker-based systematic reviews.

RESULTS

With 147,774 systematic reviews indexed in PubMed from 1990 to 2011 (accessed on 18/10/2012), only 4,431 (3%) are dedicated to biomarkers. The annual growth rate of biomarkers publications is consistently higher than non-biomarkers publications, showing the growth in biomarkers research. From 20 years of systematic review publications indexed in PubMed, we identified a bias in systematic reviews against the inclusion of biomarker-based RCTs.

CONCLUSIONS

With the realisation of genome-based personalised medicine, biomarkers are becoming important for clinical decision making. The bias against the inclusion of biomarkers in systematic reviews leads to medical practitioners deprive of important information they require to address clinical questions. Sparse or weak evidence and lack of genetic training for systematic reviewers may contribute to this trend.

Evaluation of excess statistical significance in meta-analyses of 98 biomarker associations with cancer risk

BACKGROUND

Numerous biomarkers have been associated with cancer risk. We assessed whether there is evidence for excess statistical significance in results of cancer biomarker studies, suggesting biases.

METHODS

We systematically searched PubMed for meta-analyses of nongenetic biomarkers and cancer risk. The number of observed studies with statistically significant results was compared with the expected number, based on the statistical power of each study under different assumptions for the plausible effect size. We also evaluated small-study effects using asymmetry tests. All statistical tests were two-sided.

RESULTS

We included 98 meta-analyses with 847 studies. Forty-three meta-analyses (44%) found nominally statistically significant summary effects (random effects). The proportion of meta-analyses with statistically significant effects was highest for infectious agents (86%), inflammatory (67%), and insulin-like growth factor (IGF)/insulin system (52%) biomarkers. Overall, 269 (32%) individual studies observed nominally statistically significant results. A statistically significant excess of the observed over the expected number of studies with statistically significant results was seen in 20 meta-analyses. An excess of observed vs expected was observed in studies of IGF/insulin (P ≤ .04) and inflammation systems (P ≤ .02). Only 12 meta-analyses (12%) had a statistically significant summary effect size, more than 1000 case patients, and no hints of small-study effects or excess statistical significance; only four of them had large effect sizes, three of which pertained to infectious agents (Helicobacter pylori, hepatitis and human papilloma viruses).

CONCLUSIONS

Most well-documented biomarkers of cancer risk without evidence of bias pertain to infectious agents. Conversely, an excess of statistically significant findings was observed in studies of IGF/insulin and inflammation systems, suggesting reporting biases.

Candidate and non-candidate genes in behavior genetics

In this review we discuss recent developments in psychiatric genetics: on the one hand, studies using whole genome approaches (genome-wide association studies (GWAS) and exome sequencing) are coming close to finding genes and molecular variants that contribute to disease susceptibility; on the other candidate genes, such as the serotonin transporter, continue to dominate in genetic studies of brain imaging phenotypes and in protracted searches for gene by environment interactions. These two areas intersect, in that new information about genetic effects from whole genome approaches, should (but does not always) inform the single locus analyses.