Registration of observational studies: is it time?

Methodology of clinical trials on sodium-glucose cotransporter 2 inhibitors registered on ClinicalTrials.gov: a cross-sectional study

BACKGROUND/OBJECTIVE

The research on sodium-glucose cotransporter 2 (SGLT2) inhibitors has been increasing rapidly in the last decade, as well as indications for their use. This study aimed to analyze the methodological characteristics of clinical trials on SGLT2 inhibitors registered on ClinicalTrials.gov.

DESIGN

We conducted a cross-sectional study of trials on SGLT2 inhibitors registered on ClinicalTrials.gov up to November 11, 2022. We included clinical trials that tested SGLT2 inhibitors for any clinical condition, as a single or combined SGLT2 therapy, compared to any other medication or placebo and mapped their characteristics.

RESULTS

We identified 1102 eligible trials on 14 different SGLT2 inhibitors. The first trial registration was in 2005. There were 993 (90%) interventional and 109 (10%) observational trials. Most trials were in Phase 1 (29%), Phase 3 (23%), or Phase 4 (24%). Interventional trials were mostly randomized (85%); almost half of them did not use masking (44%). Trials on empagliflozin, dapagliflozin, and canagliflozin accounted for 75% of all trials. More than 60% of trials included patients with diabetes mellitus, 13% included only healthy subjects, and 12% included patients with heart diseases. Overall, these trials included more than 9.5 million participants (~ 312,000 of which in interventional studies). Almost 65% of all clinical trials were industry-funded. Most trials were completed (60%) and 35% of those reported results. For trials that are obligated to report results by the Food and Drugs Administration (FDA), 88% of them did so. Trials fully or partially funded by industry more frequently published results compared to non-industry funded trials (46.1% vs. 11.2%; p < 0.001).

CONCLUSIONS

The number of registered trials on SGLT2 inhibitors is increasing progressively along with expanding indications for its use, shifting from diabetes mellitus to cardiovascular and renal diseases. Public reporting of trial results improved with time but remains suboptimal.

Assessing the transparency in reporting of clinical trials investigating manual therapy interventions for low back pain: A methodological review

RATIONALE

Low back pain (LBP) is a common condition with a significant societal burden. Manual therapy is an effective treatment for LBP and recommended in clinical practice guidelines. While the quantity of literature supporting the use of manual therapy is large, the methodological quality and transparency of this collective work are unclear.

AIMS AND OBJECTIVES

Explore the transparency in reporting of clinical trials assessing manual therapy interventions in patients with LBP by comparing planned components in the trial registration with what was reported in the published manuscript.

METHODS

Three databases were searched to identify trials assessing the treatment effect of manual therapy for LBP from January 2005 to May 2023. Studies were included if the manual therapy consisted of thrust manipulations, mobilizations or muscle energy techniques.

RESULTS

From 4462 studies initially identified, 167 studies remained in the final review after title, abstract and full-text review. Only 87 (52.1%) of the 167 studies were registered (n = 57 prospectively and n = 30 retrospectively). Primary outcomes in the publications were identical to the registration in 54 (62.1%) of the registered trials. Secondary outcomes in the publication were identical to the registration in 27 (31.0%) of the registered trials. The CONSORT reporting guideline was referenced in only 19 (21.8%) trials. Multiple discrepancies between registration and publication were noted for primary and secondary outcomes. All trials had eligibility criteria in the registration that matched their corresponding manuscript, while only four (4.6%) trial registrations addressed any type of statistical analysis plan.

CONCLUSION

Approximately half of the trials were not registered. Of those registered, only half were registered prospectively. Substantial discrepancies existed between registered and published outcomes that were never addressed by the authors, raising questions about potential bias. Transparency can be improved through more stringent requirements during manuscript submission to journals, and better reporting of the rationale for discrepancies between registration and publication.

Planned but ever published? A retrospective analysis of clinical prediction model studies registered on clinicaltrials.gov since 2000

OBJECTIVES

To describe the characteristics and publication outcomes of clinical prediction model studies registered on clinicaltrials.gov since 2000.

STUDY DESIGN AND SETTING

Observational studies registered on clinicaltrials.gov between January 1, 2000, and March 2, 2022, describing the development of a new clinical prediction model or the validation of an existing model for predicting individual-level prognostic or diagnostic risk were analyzed. Eligible clinicaltrials.gov records were classified by modeling study type (development, validation) and the model outcome being predicted (prognostic, diagnostic). Recorded characteristics included study status, sample size information, Medical Subject Headings, and plans to share individual participant data. Publication outcomes were analyzed by linking National Clinical Trial numbers for eligible records with PubMed abstracts.

RESULTS

Nine hundred twenty-eight records were analyzed from a possible 89,896 observational study records. Publications searches found 170 matching peer-reviewed publications for 137 clinicaltrials.gov records. The estimated proportion of records with 1 or more matching publications after accounting for time since study start was 2.8% at 2 years (95% CI: 1.7%, 3.9%), 12.3% at 5 years (9.8% to 14.9%) and 27% at 10 years (23% to 33%). Stratifying records by study start year indicated that publication proportions improved over time. Records tended to prioritize the development of new prediction models over the validation of existing models (76%; 704/928 vs. 24%; 182/928). At the time of download, 27% of records were marked as complete, 35% were still recruiting, and 14.7% had unknown status. Only 7.4% of records stated plans to share individual participant data.

CONCLUSION

Published clinical prediction model studies are only a fraction of overall research efforts, with many studies planned but not completed or published. Improving the uptake of study preregistration and follow-up will increase the visibility of planned research. Introducing additional registry features and guidance may improve the identification of clinical prediction model studies posted to clinical registries.

The majority of observational studies in leading peer-reviewed medicine journals are not registered and do not have a publicly accessible protocol: a scoping review

OBJECTIVES

Observational studies are not subject to the same requirements as randomized controlled trials, such as registration or publishing a protocol. The aim of this scoping review was to estimate the registration rate of observational studies in leading peer-reviewed medicine journals and to evaluate whether protocols were available in the public domain.

STUDY DESIGN AND SETTING

In March 2023, we searched OVID Medline for observational studies published in 2022 in the top five general medicine journals according to impact factor (The Lancet, The British Medical Journal (BMJ), The Journal of the American Medical Association, The New England Journal of Medicine, and Annals of Internal Medicine). We defined an observational study as a cohort study, a case-control study, a cross-sectional study, or a case series. Information on i) the proportion of observational studies that have been registered and ii) the proportion of observational studies that have a protocol available in the public domain was extracted from a random sample of studies.

RESULTS

Our search identified 699 studies; 290 studies were selected as full text, and a random sample of 200 studies was included. For half of the studies, the first author worked at a US institution. Most studies were cohort studies (n = 126, 63.0%) and used administrative healthcare records, electronic healthcare records, and registries. Of the 200 observational studies, 20 (10.0%) were registered. Among those, 14 were prospectively registered. Twenty-four studies (12.0%) had a protocol available in the public domain. Studies that were registered or had a protocol, were more frequently published in the BMJ (n = 12/28, 42.9%), had a first author working in the UK (n = 10/28, 35.7%) and used electronic health care records (n = 13/28, 46.4%) compared to studies with no registration and no protocol.

CONCLUSION

The rate of prospectively registered observational studies is worryingly low. Prospective registration of observational studies should be encouraged and standardized to ensure transparency in clinical research and reduce research waste.

Optimising the use of electronic medical records for large scale research in psychiatry

The explosion and abundance of digital data could facilitate large-scale research for psychiatry and mental health. Research using so-called "real world data"-such as electronic medical/health records-can be resource-efficient, facilitate rapid hypothesis generation and testing, complement existing evidence (e.g. from trials and evidence-synthesis) and may enable a route to translate evidence into clinically effective, outcomes-driven care for patient populations that may be under-represented. However, the interpretation and processing of real-world data sources is complex because the clinically important 'signal' is often contained in both structured and unstructured (narrative or "free-text") data. Techniques for extracting meaningful information (signal) from unstructured text exist and have advanced the re-use of routinely collected clinical data, but these techniques require cautious evaluation. In this paper, we survey the opportunities, risks and progress made in the use of electronic medical record (real-world) data for psychiatric research.

Prevalence of orofacial injuries resulting from trauma in individuals with cerebral palsy: A systematic review and meta-analysis

Individuals with cerebral palsy (CP) may have cognitive, sensitive, behavioral, communicative, and convulsive disorders. Because defensive reflexes are reduced by CP, the risk of orofacial trauma is greater in these individuals. This study aimed to evaluate the prevalence of orofacial injuries resulting from trauma in patients with CP. This review was reported according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) and registered in the International Prospective Register of Systematic Reviews (PROSPERO-CRD42022293570). The search was performed for articles published until January 2023 in Embase, Latin American and Caribbean Literature on Health Sciences (LILACS), PubMed/Medline, Scopus, and Web of Science databases. Gray literature was also consulted through Google Scholar, OpenGrey, ProQuest Dissertations, and Theses. Studies in which orofacial injuries due to trauma were prevalent in individuals with CP were included. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Tool. Additionally, a random-effects meta-analysis was conducted. Twelve studies were included in the synthesis, of which nine presented a low risk of bias and three presented a moderate risk. When considering the general prevalence of orofacial injuries in patients with CP, a prevalence of 34% [95% CI = 18%-52%; I2  = 98%] was observed, with enamel and dentin fractures being the most common orofacial injuries. Approximately one in three patients with CP showed at least one type of orofacial injury involving dental trauma. There is a lack of literature assessing the prevalence of these traumas in soft tissues and the evidence for this outcome remains uncertain.

Trials and tribulations of transparency related to inconsistencies between plan and conduct in peer-reviewed physiotherapy publications: A methodology review

RATIONALE

The physiotherapy profession strives to be a leader in providing quality care and strongly recognizes the value of research to guide clinical practice. Adherence to guidelines for research reporting and conduct is a significant step towards high-quality, transparent and reproducible research.

AIM/OBJECTIVE

Assess integrity between planned and conducted methodology in randomized controlled trials (RCTs) and systematic reviews (SRs) published in physiotherapy journals.

METHODS

Eighteen journals were manually searched for RCTs and SRs published from 1 July 2021 through 31 December 2021. Studies were included if the journal or specific study was indexed in PubMed and published/translated in English. Descriptive statistics determined congruence between preregistration data and publication.

RESULTS

Forty RCTs and 68 SRs were assessed. Forty-three SRs included meta-analysis (MA). Of the 34 registered RCTs, 7 (20.6%) had no discrepancy between the registration and publication. Two trials (5.9%) addressed all discrepancies, 4 (11.8%) addressed some and 21 (61.8%) did not address any discrepancies. Of the 36 registered MAs, 33 (91.7%) had discrepancies between the registration and publication. Two (5.6%) addressed all discrepancies and three (8.3%) had no discrepancies. Eight SRs without MA published information not matching their registration, and none provided justification for the discrepancies.

CONCLUSION

Most RCTs/SRs were registered; the majority had discrepancies between preregistration and publication, potentially influencing the outcomes and interpretations of findings. Journals should require preregistration and compare the submission with the registration information when assessing publication suitability. Readers should be aware of these inconsistencies and their implications when interpreting and translating results into practice.

Sensitivity analysis for causality in observational studies for regulatory science

Objective

The United States Congress passed the 21st Century Cures Act mandating the development of Food and Drug Administration guidance on regulatory use of real-world evidence. The Forum on the Integration of Observational and Randomized Data conducted a meeting with various stakeholder groups to build consensus around best practices for the use of real-world data (RWD) to support regulatory science. Our companion paper describes in detail the context and discussion of the meeting, which includes a recommendation to use a causal roadmap for study designs using RWD. This article discusses one step of the roadmap: the specification of a sensitivity analysis for testing robustness to violations of causal model assumptions.

Methods

We present an example of a sensitivity analysis from a RWD study on the effectiveness of Nifurtimox in treating Chagas disease, and an overview of various methods, emphasizing practical considerations on their use for regulatory purposes.

Results

Sensitivity analyses must be accompanied by careful design of other aspects of the causal roadmap. Their prespecification is crucial to avoid wrong conclusions due to researcher degrees of freedom. Sensitivity analysis methods require auxiliary information to produce meaningful conclusions; it is important that they have at least two properties: the validity of the conclusions does not rely on unverifiable assumptions, and the auxiliary information required by the method is learnable from the corpus of current scientific knowledge.

Conclusions

Prespecified and assumption-lean sensitivity analyses are a crucial tool that can strengthen the validity and trustworthiness of effectiveness conclusions for regulatory science.

Registration of health and medical research

Registration of health and medical research is an effective way of improving the transparency and credibility of evidence. Registration involves pre-specifying the research objectives, design, methods and analytic plan on a publicly accessible repository before conducting the study. Registration can reduce bias and improve the transparency and credibility of research findings. Registration is mandated for clinical trials, but it is also relevant to systematic reviews, observational and preclinical experimental research. This paper describes how researchers can register their research and outlines possible barriers and challenges in doing so. Widespread adoption of research registration can reduce research waste and improve evidence-informed clinical and policy decision making.

Clinical trial data-sharing policies among journals, funding agencies, foundations, and other professional organizations: a scoping review

BACKGROUND AND OBJECTIVES

To identify the similarities and differences in data-sharing policies for clinical trial data that are endorsed by biomedical journals, funding agencies, and other professional organizations. Additionally, to determine the beliefs, and opinions regarding data-sharing policies for clinical trials discussed in articles published in biomedical journals.

METHODS

Two searches were conducted, a bibliographic search for published articles that present beliefs, opinions, similarities, and differences regarding policies governing the sharing of clinical trial data. The second search analyzed the gray literature (non-peer-reviewed publications) to identify important data-sharing policies in selected biomedical journals, foundations, funding agencies, and other professional organizations.

RESULTS

A total of 471 articles were included after database search and screening, with 45 from the bibliographic search and 426 from the gray literature search. A total of 424 data-sharing policies were included. Fourteen of the 45 published articles from the bibliographic search (31.1%) discussed only advantages specific to data-sharing policies, 27 (27/45; 60%) discussed both advantages and disadvantages, and 4 (4/45; 8.9%) discussed only disadvantages specific. A total of 216 journals (of 270; 80%) specified a data-sharing policy provided by the journal itself. One hundred industry data-sharing policies were included, and 32 (32%) referenced a data-sharing policy on their website. One hundred and thirty-six (42%) organizations (of 327) specified a data-sharing policy.

CONCLUSION

We found many similarities listed as advantages to data-sharing and fewer disadvantages were discussed within the literature. Additionally, we found a wide variety of commonalities and differences-such as the lack of standardization between policies, and inadequately addressed details regarding the accessibility of research data-that exist in data-sharing policies endorsed by biomedical journals, funding agencies, and other professional organizations. Our study may not include information on all data sharing policies and our data is limited to the entities' descriptions of each policy.

What is the 'voltage drop' when an effective health promoting intervention for older adults-Choose to Move (Phase 3)-Is implemented at broad scale?

BACKGROUND

Choose to Move (CTM), an effective health-promoting intervention for older adults, was scaled-up across British Columbia, Canada. Adaptations that enable implementation at scale may lead to 'voltage drop'-diminished positive effects of the intervention. For CTM Phase 3 we assessed: i. implementation; ii. impact on physical activity, mobility, social isolation, loneliness and health-related quality of life (impact outcomes); iii. whether intervention effects were maintained; iv) voltage drop, compared with previous CTM phases.

METHODS

We conducted a type 2 hybrid effectiveness-implementation pre-post study of CTM; older adult participants (n = 1012; mean age 72.9, SD = 6.3 years; 80.6% female) were recruited by community delivery partners. We assessed CTM implementation indicators and impact outcomes via survey at 0 (baseline), 3 (mid-intervention), 6 (end-intervention) and 18 (12-month follow-up) months. We fitted mixed-effects models to describe change in impact outcomes in younger (60-74 years) and older (≥ 75 years) participants. We quantified voltage drop as percent of effect size (change from baseline to 3- and 6-months) retained in Phase 3 compared with Phases 1-2.

RESULTS

Adaptation did not compromise fidelity of CTM Phase 3 as program components were delivered as intended. PA increased during the first 3 months in younger (+1 days/week) and older (+0.9 days/week) participants (p<0.001), and was maintained at 6- and 18-months. In all participants, social isolation and loneliness decreased during the intervention, but increased during follow-up. Mobility improved during the intervention in younger participants only. Health-related quality of life according to EQ-5D-5L score did not change significantly in younger or older participants. However, EQ-5D-5L visual analog scale score increased during the intervention in younger participants (p<0.001), and this increase was maintained during follow-up. Across all outcomes, the median difference in effect size, or voltage drop, between Phase 3 and Phases 1-2 was 52.6%. However, declines in social isolation were almost two times greater in Phase 3, compared with Phases 1-2.

CONCLUSION

Benefits of health-promoting interventions-like CTM-can be retained when implemented at broad scale. Diminished social isolation in Phase 3 reflects how CTM was adapted to enhance opportunities for older adults to socially connect. Thus, although intervention effects may be reduced at scale-up, voltage drop is not inevitable.

Challenges and recommendations for high quality research using electronic health records

Harnessing Real World Data is vital to improve health care in the 21st Century. Data from Electronic Health Records (EHRs) are a rich source of patient centred data, including information on the patient's clinical condition, laboratory results, diagnoses and treatments. They thus reflect the true state of health systems. However, access and utilisation of EHR data for research presents specific challenges. We assert that using data from EHRs effectively is dependent on synergy between researchers, clinicians and health informaticians, and only this will allow state of the art methods to be used to answer urgent and vital questions for patient care. We propose that there needs to be a paradigm shift in the way this research is conducted - appreciating that the research process is iterative rather than linear. We also make specific recommendations for organisations, based on our experience of developing and using EHR data in trusted research environments.

Global perspective on pediatric growth hormone registries: a systematic review

BACKGROUND

Registries are considered valuable data sources for identification of pediatric conditions treated with growth hormone (GH), and their follow-up. Currently, there is no systematic literature review on the scope and characteristics of pediatric GH registries. Therefore, the purpose of this systematic review is to identify worldwide registries reported on pediatric GH treatment and to provide a summary of their main characteristics.

CONTENT

Pediatric GH registries were identified through a systematic literature review. The search was performed on all related literature published up to January 30th, 2021. Basic information on pediatric GH registries, their type and scope, purpose, sources of data, target conditions, reported outcomes, and important variables were analyzed and presented.

SUMMARY

Twenty two articles, reporting on 20 pediatric GH registries, were included in this review. Industrial funding was the most common funding source. The main target conditions included in the pediatric GH registries were: growth hormone deficiency, Turner syndrome, Prader Willi syndrome, small for gestational age, idiopathic short stature, and chronic renal insufficiency. The main objectives in establishing and running pediatric GH registries were assessing the safety and effectiveness of the treatment, describing the epidemiological aspects of target growth conditions and populations, serving public health surveillance, predicting and measuring treatment outcomes, exploring new and useful aspects of GH treatment, and improving the quality of patient care.

OUTLOOK

This systematic review provides a global perspective on pediatric GH registries which can be used as a basis for the design and development of new GH registry systems at both national and international levels.

What are the effects of different elements of media on radicalization outcomes? A systematic review

BACKGROUND

Most national counter-radicalization strategies identify the media, and particularly the Internet as key sources of risk for radicalization. However, the magnitude of the relationships between different types of media usage and radicalization remains unknown. Additionally, whether Internet-related risk factors do indeed have greater impacts than other forms of media remain another unknown. Overall, despite extensive research of media effects in criminology, the relationship between media and radicalization has not been systematically investigated.

OBJECTIVES

This systematic review and meta-analysis sought to (1) identify and synthesize the effects of different media-related risk factors at the individual level, (2) identify the relative magnitudes of the effect sizes for the different risk factors, and (3) compare the effects between outcomes of cognitive and behavioral radicalization. The review also sought to examine sources of heterogeneity between different radicalizing ideologies.

SEARCH METHODS

Electronic searches were carried out in several relevant databases and inclusion decisions were guided by a published review protocol. In addition to these searches, leading researchers were contacted to try and identify unpublished or unidentified research. Hand searches of previously published reviews and research were also used to supplement the database searches. Searches were carried out until August 2020.

SELECTION CRITERIA

The review included quantitative studies that examined at least one media-related risk factor (such as exposure to, or usage of a particular medium or mediated content) and its relationship to either cognitive or behavioral radicalization at the individual level.

DATA COLLECTION AND ANALYSIS

Random-effects meta-analysis was used for each risk factor individually and risk factors were arranged in rank-order. Heterogeneity was explored using a combination of moderator analysis, meta-regression, and sub-group analysis.

RESULTS

The review included 4 experimental and 49 observational studies. Most of the studies were judged to be of low quality and suffer from multiple, potential sources of bias. From the included studies, effect sizes pertaining to 23 media-related risk factors were identified and analyzed for the outcome of cognitive radicalization, and two risk factors for the outcome of behavioral radicalization. Experimental evidence demonstrated that mere exposure to media theorized to increase cognitive radicalization was associated with a small increase in risk (g = 0.08, 95% confidence interval [CI] [-0.03, 19]). A slightly larger estimate was observed for those high in trait aggression (g = 0.13, 95% CI [0.01, 0.25]). Evidence from observational studies shows that for cognitive radicalization, risk factors such as television usage have no effect (r = 0.01, 95% CI [-0.06, 0.09]). However, passive (r = 0.24, 95% CI [0.18, 0.31]) and active (r = 0.22, 95% CI [0.15, 0.29]) forms of exposure to radical content online demonstrate small but potentially meaningful relationships. Similar sized estimates for passive (r = 0.23, 95% CI [0.12, 0.33]) and active (r = 0.28, 95% CI [0.21, 0.36]) forms of exposure to radical content online were found for the outcome of behavioral radicalization.

AUTHORS' CONCLUSIONS

Relative to other known risk factors for cognitive radicalization, even the most salient of the media-related risk factors have comparatively small estimates. However, compared to other known risk factors for behavioral radicalization, passive and active forms of exposure to radical content online have relatively large and robust estimates. Overall, exposure to radical content online appears to have a larger relationship with radicalization than other media-related risk factors, and the impact of this relationship is most pronounced for behavioral outcomes of radicalization. While these results may support policy-makers' focus on the Internet in the context of combatting radicalization, the quality of the evidence is low and more robust study designs are needed to enable the drawing of firmer conclusions.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

Toward more rigorous and informative nutritional epidemiology: The rational space between dismissal and defense of the status quo

To date, nutritional epidemiology has relied heavily on relatively weak methods including simple observational designs and substandard measurements. Despite low internal validity and other sources of bias, claims of causality are made commonly in this literature. Nutritional epidemiology investigations can be improved through greater scientific rigor and adherence to scientific reporting commensurate with research methods used. Some commentators advocate jettisoning nutritional epidemiology entirely, perhaps believing improvements are impossible. Still others support only normative refinements. But neither abolition nor minor tweaks are appropriate. Nutritional epidemiology, in its present state, offers utility, yet also needs marked, reformational renovation. Changing the status quo will require ongoing, unflinching scrutiny of research questions, practices, and reporting-and a willingness to admit that "good enough" is no longer good enough. As such, a workshop entitled "Toward more rigorous and informative nutritional epidemiology: the rational space between dismissal and defense of the status quo" was held from July 15 to August 14, 2020. This virtual symposium focused on: (1) Stronger Designs, (2) Stronger Measurement, (3) Stronger Analyses, and (4) Stronger Execution and Reporting. Participants from several leading academic institutions explored existing, evolving, and new better practices, tools, and techniques to collaboratively advance specific recommendations for strengthening nutritional epidemiology.

COVID-19-related research in Africa: a cross-sectional review of the International Clinical Trial Registration Platform (ICTRP)

Objective

The declaration of the coronavirus disease (COVID-19), a pandemic in early 2020, has seen an upsurge in research globally to fill gaps in the epidemiology of the SARS-CoV-2 virus impact on health care and clinical management, as well as possible prevention and treatment modalities. Published literature on the different types of COVID-19 research conducted globally is varied and is particularly limited in Africa. This study sets out to describe the COVID-19-related research registered and conducted on the African continent.

Methods

This is a cross-sectional study of all COVID-19-related studies available in the WHO’s International Clinical Trials Registry Platform (ICTRP) repository. We extracted studies registered from March 1, 2020, to July 15, 2021. A descriptive analysis of the extracted data was performed, and the findings were presented.

Results

At extraction, a total of 12,533 COVID-19-related studies were listed on the ICTRP portal. We included 9803 studies, after excluding 2060 duplicate records and 686 records without a site/country. While 9347 studies (96%) were conducted outside of Africa, only 456 studies (4%) were conducted in the African continent, of which 270 (59.2%) were interventional studies, and 184 (40.4%) were observational studies. About 80% of the studies were conducted in Egypt and South Africa, and most of these involved testing of drugs and biologicals.

Conclusion

The African continent hosts considerably fewer COVID-19-related research compared to other parts of the world. This may have implications on scientific evidence available for implementing COVID-19 control efforts. There is, therefore, a need for local funding and ownership of research projects and north-south collaboration in research.

Designing deep learning studies in cancer diagnostics

The number of publications on deep learning for cancer diagnostics is rapidly increasing, and systems are frequently claimed to perform comparable with or better than clinicians. However, few systems have yet demonstrated real-world medical utility. In this Perspective, we discuss reasons for the moderate progress and describe remedies designed to facilitate transition to the clinic. Recent, presumably influential, deep learning studies in cancer diagnostics, of which the vast majority used images as input to the system, are evaluated to reveal the status of the field. By manipulating real data, we then exemplify that much and varied training data facilitate the generalizability of neural networks and thus the ability to use them clinically. To reduce the risk of biased performance estimation of deep learning systems, we advocate evaluation in external cohorts and strongly advise that the planned analyses, including a predefined primary analysis, are described in a protocol preferentially stored in an online repository. Recommended protocol items should be established for the field, and we present our suggestions.

The reporting of observational studies of drug effectiveness and safety: recommendations to extend existing guidelines

INTRODUCTION

The use of observational data to assess drug effectiveness and safety can provide relevant information, much of which may not be feasible to obtain through randomized clinical trials. Because observational studies provide critical drug safety and effectiveness information that influences drug policy and prescribing practices, transparent, consistent, and accurate reporting of these studies is critical.

AREAS COVERED

We provide recommendations to extend existing reporting guidelines, covering the main components of primary research studies (methods, results, discussion).

EXPERT OPINION

Our recommendations include extending drug safety and effectiveness guidelines to include explicit checklist items on: study registration, causal diagrams, rationale for measures of effect, comprehensive assessment of bias, comprehensive data cleaning steps, drug equivalents, subject-level drug data visualization, sex and gender-based analyses and results, patient-oriented outcomes, and patient involvement in research.

Use of real-world evidence in economic assessments of pharmaceuticals in the United States

BACKGROUND: Despite the increasing interest in expanding the use of real-world evidence (RWE) in economic assessments of pharmaceuticals, decision makers face uncertainty about how RWE should be used. OBJECTIVE: To assess the use of RWE in economic assessments of drugs by the Institute for Clinical and Economic Review (ICER). METHODS: We reviewed cost-effectiveness and budget impact analyses in final evidence reports of pharmaceuticals published by ICER. We calculated the total number of RWE uses and the proportion of model inputs informed by RWE per report. We classified model inputs into 15 categories based on their attributes and then examined what category each RWE informed to classify the reason for RWE use. Finally, we characterized RWE by study design, data source, and sponsor type. RESULTS: We identified 33 reports, all of which used RWE; the mean RWE use per report was 12 (range = 4-26). The average proportion of model inputs informed by RWE per report was 32.7%, but this proportion had a wide range (range = 4.1%-76.9%). RWE was most commonly used for disease progression inputs (28.7%) and health care resource utilization and costs (21.1%), but was rarely used for drug-specific clinical outcomes such as effectiveness (1.5%), adverse drug event rates (0.5%), and discontinuation rates (1.2%). The most frequently used study design was a retrospective cohort (56.6%), and the most frequently used data source was registry data (41.4%). About a third (30.2%) of RWE was industry-sponsored. CONCLUSIONS: RWE has been commonly used to inform pharmaceutical value assessments conducted by ICER. However, there has been relatively limited use of RWE to inform drug-specific effectiveness, despite calls for greater inclusion of RWE in value assessments for real-world drug effectiveness. DISCLOSURES: This study was funded by the University of Washington School of Pharmacy Corporate Advisory Board Health Tech Fund (HTF). The funder had no role in management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; and the decision to submit the manuscript for publication. All authors were employed by the CHOICE Institute, University of Washington School of Pharmacy, at the time of the study. Carlson reports grants from the Institute for Clinical and Economic Review during the conduct of the study and personal fees from Bayer, Adaptive Biotechnologies, Allergan, Galderma, and ViFor Pharma, unrelated to this study. Veenstra reports personal fees from several manufacturers unrelated to this study. The other authors have nothing to disclose.

Characteristics and trends of clinical studies primarily sponsored by China in WHO primary registries between 2009 and 2018: a cross-sectional survey

OBJECTIVES

To analyse characteristics and developmental trends of clinical study registration primarily sponsored by China's institutions during 2009-2018.

SETTING

Registration information registered prior to 31 December 2018 was obtained from the International Clinical Trials Registry Platform (ICTRP) source registries, including Chinese Clinical Trial Registry, ClinicalTrials.gov, Australian New Zealand Clinical Trials Registry and International Standard Randomised Controlled Trial Number. Registration information on other ICTRP source registries was collected from the ICTRP.

DESIGN

A cross-sectional analysis was performed. The studies sponsored by mainland China's institutions (not including institutions in Hong Kong SAR, Macau SAR or Taiwan of China) as of 31 December 2018 were filtered. For duplicate registrations, only the records with the earliest registration date were included. Global registrations were summarised for comparison.

RESULTS

A total of 32 557 China-sponsored studies and 478 261 global studies were included. The registered China-sponsored studies, increased from a cumulative number of 1333 in 2009 to 32 557 in 2018, were less likely to have industry involvement (14% vs 30%) and more likely to be registered prospectively (63% vs 45%) than the global registrations during 2009-2018. The top three most studied health conditions were lung cancer (4.2%), diabetes (3.8%) and ischaemic heart disease (3.2%). Depression and depressive disorders and chronic obstructive pulmonary disease (COPD) each represented 1.1% of registered China-sponsored studies. Phase 2 and phase 3 trials together accounted for 30%, notably lower than the global level (53%). The registered studies responding to an individual participant data (IPD) sharing plan had increased since 2016, but the proportions of studies indicating 'yes' were still at a low level and accounted for 5% of the registered China-sponsored studies and global registrations.

CONCLUSIONS

Clinical study registration activity in China has been substantial during 2009-2018. Some diseases with a high disease burden in China (depression and depressive disorders and COPD) were underrepresented by the proportion of registered studies. The accessibility of IPD merits improvement.

Ethics committees for clinical experimentation at international level with a focus on Italy

Guiding legislation and associated bureaucracy for the ethical review of clinical trials observational studies and food related research play an important role in the competitiveness of a nation in the face of tough global competition to attract sponsors and investigators. This is of particular relevance in the case of multicentre trials and multidisciplinary research. Accordingly, in this report we tried to gather in-depth knowledge of the current role and practices of ethics committees nationwide in both clinical and research settings. This mini-review aims to describe the formulation and organization of ethical committees in Italy in order to provide a focus for deliberations on ethical issues in medical and scientific research in line with human rights, as set out in the European Union charter. Furthermore, we evaluated the impact of an institution's ethical committee intervention on reducing the time required to obtain an opinion from Research Ethics Committees by guiding investigators in addressing ethical issues in their proposed studies.

Standardized Protocol Items Recommendations for Observational Studies (SPIROS) for Observational Study Protocol Reporting Guidelines: Protocol for a Delphi Study

BACKGROUND

Approximately 90% of currently published clinical and public health research is in the form of observational studies. Having a detailed and registered study protocol prior to data collection is important in any empirical study. Without this, there is no reliable way to assess the occurrence of publication bias, outcome reporting bias, and other protocol deviations. However, there is currently no solid guidance available on the information that a protocol for an observational study should contain.

OBJECTIVE

The aim of this study is to formulate the Standardized Protocol Items Recommendations for Observational Studies (SPIROS) reporting guidelines, which focus on 3 main study designs of analytical epidemiology: cohort, case-control, and cross-sectional studies.

METHODS

A scoping review of published protocol papers of observational studies in epidemiology will identify candidate items for the SPIROS reporting guidelines. The list of items will be extended with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist items and recommendations from the SPIROS steering committee. This long list serves as the basis for a 2-round Delphi survey among experts to obtain consensus on which items to include. Each candidate item from the long list will be rated on a 5-point Likert scale to assess relevance for inclusion in the SPIROS reporting guidelines. Following the Delphi survey, an expert-driven consensus workshop will be convened to finalize the reporting guidelines.

RESULTS

A scoping review of published observational study protocols has been completed, with 59 candidate items identified for inclusion into the Delphi survey, itself launched in early 2020.

CONCLUSIONS

This project aims to improve the timeliness, completeness, and clarity of study protocols of observational studies in analytical epidemiology by producing expert-based recommendations of items to be addressed. These reporting guidelines will facilitate and encourage researchers to prepare and register study protocols of sufficient quality prior to data collection in order to improve the transparency, reproducibility, and quality of observational studies.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/17864.

Social Isolation and Cognitive Function in Later Life: A Systematic Review and Meta-Analysis

BACKGROUND

There is some evidence to suggest that social isolation may be associated with poor cognitive function in later life. However, findings are inconsistent and there is wide variation in the measures used to assess social isolation.

OBJECTIVE

We conducted a systematic review and meta-analysis to investigate the association between social isolation and cognitive function in later life.

METHODS

A search for longitudinal studies assessing the relationship between aspects of social isolation (including social activity and social networks) and cognitive function (including global measures of cognition, memory, and executive function) was conducted in PsycInfo, CINAHL, PubMed, and AgeLine. A random effects meta-analysis was conducted to assess the overall association between measures of social isolation and cognitive function. Sub-analyses investigated the association between different aspects of social isolation and each of the measures of cognitive function.

RESULTS

Sixty-five articles were identified by the systematic review and 51 articles were included in the meta-analysis. Low levels of social isolation characterized by high engagement in social activity and large social networks were associated with better late-life cognitive function (r = 0.054, 95% CI: 0.043, 0.065). Sub-analyses suggested that the association between social isolation and measures of global cognitive function, memory, and executive function were similar and there was no difference according to gender or number of years follow-up.

CONCLUSIONS

Aspects of social isolation are associated with cognitive function in later life. There is wide variation in approaches to measuring social activity and social networks across studies which may contribute to inconsistencies in reported findings.

Improving transparency to build trust in real-world secondary data studies for hypothesis testing-Why, what, and how: recommendations and a road map from the real-world evidence transparency initiative

Real-world data (RWD) and the derivations of these data into real-world evidence (RWE) are rapidly expanding from informing healthcare decisions at the patient and health system level to influencing major health policy decisions, including regulatory approvals and coverage. Recent examples include the approval of palbociclib in combination with endocrine therapy for male breast cancer and the inclusion of RWE in the label of paliperidone palmitate for schizophrenia. This interest has created an urgency to develop processes that promote trust in the evidence-generation process. Key stakeholders and decision-makers include patients and their healthcare providers; learning health systems; health technology assessment bodies and payers; pharmacoepidemiologists and other clinical reseachers, and policy makers interested in bioethical and regulatory issues. A key to optimal uptake of RWE is transparency of the research process to enable decision-makers to evaluate the quality of the methods used and the applicability of the evidence that results from the RWE studies. Registration of RWE studies-particularly for hypothesis evaluating treatment effectiveness (HETE) studies-has been proposed to improve transparency, trust, and research replicability. Although registration would not guarantee better RWE studies would be conducted, it would encourage the prospective disclosure of study plans, timing, and rationale for modifications. A joint task force of the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) and the International Society for Pharmacoepidemiology (ISPE) recommended that investigators preregister their RWE studies and post their study protocols in a publicly available forum before starting studies to reduce publication bias and improve the transparency of research methods. Recognizing that published recommendations alone are insufficient, especially without accessible registration options and with no incentives, a group of experts gathered on February 25 and 26, 2019, in National Harbor, Maryland, to explore the structural and practical challenges to the successful implementation of the recommendations of the ISPOR/ISPE task force for preregistration. This positioning article describes a plan for making registration of HETE RWE studies routine. The plan includes specifying the rationale for registering HETE RWE studies, the studies that should be registered, where and when these studies should be registered, how and when analytic deviations from protocols should be reported, how and when to publish results, and incentives to encourage registration. Table 1 summarizes the rationale, goals, and potential solutions that increase transparency, in addition to unique concerns about secondary data studies. Definitions of terms used throughout this report are provided in Table 2.

Improving Transparency to Build Trust in Real-World Secondary Data Studies for Hypothesis Testing-Why, What, and How: Recommendations and a Road Map from the Real-World Evidence Transparency Initiative

Real-world data (RWD) and the derivations of these data into real-world evidence (RWE) are rapidly expanding from informing healthcare decisions at the patient and health system level to influencing major health policy decisions, including regulatory approvals and coverage. Recent examples include the approval of palbociclib in combination with endocrine therapy for male breast cancer and the inclusion of RWE in the label of paliperidone palmitate for schizophrenia. This interest has created an urgency to develop processes that promote trust in the evidence-generation process. Key stakeholders and decision-makers include patients and their healthcare providers; learning health systems; health technology assessment bodies and payers; pharmacoepidemiologists and other clinical reseachers, and policy makers interested in bioethical and regulatory issues. A key to optimal uptake of RWE is transparency of the research process to enable decision-makers to evaluate the quality of the methods used and the applicability of the evidence that results from the RWE studies. Registration of RWE studies-particularly for hypothesis evaluating treatment effectiveness (HETE) studies-has been proposed to improve transparency, trust, and research replicability. Although registration would not guarantee better RWE studies would be conducted, it would encourage the prospective disclosure of study plans, timing, and rationale for modifications. A joint task force of the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) and the International Society for Pharmacoepidemiology (ISPE) recommended that investigators preregister their RWE studies and post their study protocols in a publicly available forum before starting studies to reduce publication bias and improve the transparency of research methods. Recognizing that published recommendations alone are insufficient, especially without accessible registration options and with no incentives, a group of experts gathered on February 25 and 26, 2019, in National Harbor, Maryland, to explore the structural and practical challenges to the successful implementation of the recommendations of the ISPOR/ISPE task force for preregistration. This positioning article describes a plan for making registration of HETE RWE studies routine. The plan includes specifying the rationale for registering HETE RWE studies, the studies that should be registered, where and when these studies should be registered, how and when analytic deviations from protocols should be reported, how and when to publish results, and incentives to encourage registration. Table 1 summarizes the rationale, goals, and potential solutions that increase transparency, in addition to unique concerns about secondary data studies. Definitions of terms used throughout this report are provided in Table 2.

Characteristics of Neuropsychiatric Mobile Health Trials: Cross-Sectional Analysis of Studies Registered on ClinicalTrials.gov

BACKGROUND

The development of mobile health (mHealth) technologies is progressing at a faster pace than that of the science to evaluate their validity and efficacy. Under the International Committee of Journal Medical Editors (ICMJE) guidelines, clinical trials that prospectively assign people to interventions should be registered with a database before the initiation of the study.

OBJECTIVE

The aim of this study was to better understand the smartphone mHealth trials for high-burden neuropsychiatric conditions registered on ClinicalTrials.gov through November 2018, including the number, types, and characteristics of the studies being conducted; the frequency and timing of any outcome changes; and the reporting of results.

METHODS

We conducted a systematic search of ClinicalTrials.gov for the top 10 most disabling neuropsychiatric conditions and prespecified terms related to mHealth. According to the 2016 World Health Organization Global Burden of Disease Study, the top 10 most disabling neuropsychiatric conditions are (1) stroke, (2) migraine, (3) major depressive disorder, (4) Alzheimer disease and other dementias, (5) anxiety disorders, (6) alcohol use disorders, (7) opioid use disorders, (8) epilepsy, (9) schizophrenia, and (10) other mental and substance use disorders. There were no date, location, or status restrictions.

RESULTS

Our search identified 135 studies. A total of 28.9% (39/135) of studies evaluated interventions for major depressive disorder, 14.1% (19/135) of studies evaluated interventions for alcohol use disorders, 12.6% (17/135) of studies evaluated interventions for stroke, 11.1% (15/135) of studies evaluated interventions for schizophrenia, 8.1% (11/135) of studies evaluated interventions for anxiety disorders, 8.1% (11/135) of studies evaluated interventions for other mental and substance use disorders, 7.4% (10/135) of studies evaluated interventions for opioid use disorders, 3.7% (5/135) of studies evaluated interventions for Alzheimer disease or other dementias, 3.0% (4/135) of studies evaluated interventions for epilepsy, and 3.0% (4/135) of studies evaluated interventions for migraine. The studies were first registered in 2008; more than half of the studies were registered from 2016 to 2018. A total of 18.5% (25/135) of trials had results reported in some publicly accessible location. Across all the studies, the mean estimated enrollment (reported by the study) was 1078, although the median was only 100. In addition, across all the studies, the actual reported enrollment was lower, with a mean of 249 and a median of 80. Only about a quarter of the studies (35/135, 25.9%) were funded by the National Institutes of Health.

CONCLUSIONS

Despite the increasing use of health-based technologies, this analysis of ClinicalTrials.gov suggests that only a few apps for high-burden neuropsychiatric conditions are being clinically evaluated in trials.

Unravelling the association between accelerometer-derived physical activity and adiposity among preschool children: A systematic review and meta-analyses

Evidence on the association between physical activity (PA) and adiposity in young children is inconclusive. A systematic review and meta-analyses were conducted to examine associations between accelerometer-derived PA and varying adiposity outcomes in preschool children. Searches were conducted in Embase, MEDLINE and Web of Science to identify studies on the association between total PA, sedentary behaviour or different PA intensities and adiposity in children aged 2 to 7 years. Separate random effects meta-analyses were performed for varying PA intensities and adiposity outcomes. Fifty-six articles were included in the review and 48 in the meta-analyses. There was substantial evidence of an inverse association between moderate-to-vigorous- or vigorous PA and body fat percentage (stdβ [SE] = -0.162[0.041]; 5 studies), weight status (r = -0.120, P<.001; 11 studies), fat mass (stdβ [SE] = -0.103[0.051]; 5 studies), fat mass index (stdβ [SE] = -0.121[0.036]; 2 studies) and skinfold thickness (stdβ [SE] = -0.145[0.036]; 4 studies). However, total PA, sedentary behaviour, and different PA intensities were not associated with body mass index (BMI) or waist circumference. Adiposity levels were lower among preschool children engaged in more (moderate-to-) vigorous PA compared with their peers, but no associations between PA and BMI or waist circumference were found.

DEBATE-statistical analysis plans for observational studies

Background

All clinical research benefits from transparency and validity. Transparency and validity of studies may increase by prospective registration of protocols and by publication of statistical analysis plans (SAPs) before data have been accessed to discern data-driven analyses from pre-planned analyses.

Main message

Like clinical trials, recommendations for SAPs for observational studies increase the transparency and validity of findings. We appraised the applicability of recently developed guidelines for the content of SAPs for clinical trials to SAPs for observational studies. Of the 32 items recommended for a SAP for a clinical trial, 30 items (94%) were identically applicable to a SAP for our observational study. Power estimations and adjustments for multiplicity are equally important in observational studies and clinical trials as both types of studies usually address multiple hypotheses. Only two clinical trial items (6%) regarding issues of randomisation and definition of adherence to the intervention did not seem applicable to observational studies. We suggest to include one new item specifically applicable to observational studies to be addressed in a SAP, describing how adjustment for possible confounders will be handled in the analyses.

Conclusion

With only few amendments, the guidelines for SAP of a clinical trial can be applied to a SAP for an observational study. We suggest SAPs should be equally required for observational studies and clinical trials to increase their transparency and validity.

Frequentist versus Bayesian approaches to multiple testing

Multiple tests arise frequently in epidemiologic research. However, the issue of multiplicity adjustment is surrounded by confusion and controversy, and there is no uniform agreement on whether or when adjustment is warranted. In this paper we compare frequentist and Bayesian frameworks for multiple testing. We argue that the frequentist framework leads to logical difficulties, and is unable to distinguish between relevant and irrelevant multiplicity adjustments. We further argue that these logical difficulties resolve within the Bayesian framework, and that the Bayesian framework makes a clear and coherent distinction between relevant and irrelevant adjustments. We use Directed Acyclic Graphs to illustrate the differences between the two frameworks, and to motivate our arguments.

NIH Policies on Experimental Studies with Humans

The U.S. National Institutes of Health clinical trials policies will apply broadly to studies involving experimental manipulations of humans. These studies will require registration and reporting in ClinicalTrials.gov, grant application submission under a clinical trials funding opportunity announcement, and Good Clinical Practice training for investigators.

Analysis of the first 2645 registrations at the research registry®: A global repository for all study types involving human participants

BACKGROUND

The Declaration of Helsinki has called for the registration of all research studies involving human participants. Despite this, prior registries did not allow registration certain study types, or retrospective registration. The Research Registry^® (www.researchregistry.com) was established in 2015 to provide a venue of registration for any study involving human participants.

METHODS

and analysis: This retrospective database analysis describes the first 3000 registrations received by the Research Registry^®. Since the launch of the Registry in 2015, we have collected data on each registration and excluded inappropriate registrations through a weekly curation process. The characteristics of all studies registered is presented. Each registration was marked against a quality score by two researchers acting independently, and we describe how this has changed over time. No ethical approval was required for this data only study including no human participants.

RESULTS

Of 3000 registrations, we included 2645 that were submitted to the registry between February 2015 and October 2017. The number of registrations increased year on year, and we now receive between 60 and 80 registrations per month. One fifth of registrations were from China (537 [20.3%]). Retrospective observational studies were most commonly registered (1125 [42.5%]), and studies included in excess of 20 million patients (median 80 [IQR:25-200]). The quality score of registrations improved over the time (Kruskal-Wallis p < 0.05), and the 'control/comparator' component of the quality score was most poorly completed (completed by 1199 [54%]).

CONCLUSION

The Research Registry^® has received registrations on over 2500 registrations, including in excess of 20 million patients, with the quality of registrations improving over time. Retrospective observational studies and case series are the most commonly registered.

Clinical trials involving positron emission tomography and prostate cancer: an analysis of the ClinicalTrials.gov database

Background

The goal of this study is to evaluate the status and future perspectives of clinical trials on positron emission tomography in prostate cancer for diagnostic or therapeutic as well as for surveillance purposes.

Methods

The www.ClinicalTrials.gov database was searched on the 20th of January 2017 for all trials containing terms describing “prostate cancer” (prostate, prostatic, malignant, malignancy, cancer, tumor) and “positron emission tomography”. In total 167 trials were identified. Trials that included diseases other than PCa were excluded (n = 27; 16%). Furthermore, we excluded trials (n = 4, 2%) withdrawn prior to first patient enrollment. The remaining trials (n = 137, 82%) were selected for further manual classification analysis.

Results

One hundred thirty-seven trials were detected and analyzed. Majority of trials were in “active” recruitment status (n = 46, 34%) followed by trials that had been “completed” - (n = 34, 25%) and trials with “closed recruitment but active follow-up” (n = 23, 17%). Phase 1 and 2 comprised 46% of the complete trial portfolio. Locally confined disease was of major interest (n = 46, 34%), followed by metastatic disease – not otherwise specified (n = 43, 13%). Evaluation of PET was the primary goal of the trial in 114 (83%) cases. Most of the trials evaluated only one agent (n = 122, 89%). Choline and PSMA represented two major groups (total 50%) and they were equally distributed across trial portfolio with 25% (n = 34) each. PSMA trials showed the highest average annual growth rate of 56%. The trials were conducted in 17 countries.

Conclusion

The scientific community is showing a strong and ever-growing interest in the field and we expect that in the coming years, more phase III trials will be initiated ultimately delivering the required Level 1 evidence.

Electronic supplementary material

The online version of this article (10.1186/s13014-018-1057-3) contains supplementary material, which is available to authorized users.

The replication crisis in epidemiology: snowball, snow job, or winter solstice?

PURPOSE OF REVIEW

Like a snowball rolling down a steep hill, the most recent crisis over the perceived lack of reproducibility of scientific results has outpaced the evidence of crisis. It has led to new actions and new guidelines that have been rushed to market without plans for evaluation, metrics for success, or due consideration of the potential for unintended consequences.

RECENT FINDINGS

The perception of the crisis is at least partly a snow job, heavily influenced by a small number of centers lavishly funded by a single foundation, with undue and unsupported attention to preregistration as a solution to the perceived crisis. At the same time, the perception of crisis provides an opportunity for introspection. Two studies' estimates of association may differ because of undue attention on null hypothesis statistical testing, because of differences in the distribution of effect modifiers, because of differential susceptibility to threats to validity, or for other reasons. Perhaps the expectation of what reproducible epidemiology ought to look like is more misguided than the practice of epidemiology. We advocate for the idea of "replication and advancement." Studies should not only replicate earlier work, but also improve on it in by enhancing the design or analysis.

SUMMARY

Abandoning blind reliance on null hypothesis significance testing for statistical inference, finding consensus on when pre-registration of non-randomized study protocols has merit, and focusing on replication and advance are the most certain ways to emerge from this solstice for the better.

How to avoid common problems when using ClinicalTrials.gov in research: 10 issues to consider

ClinicalTrials.gov, a repository of information about clinical studies and their results, together with specialised search tools, provides a unique window into the clinical research enterprise, which includes all initiated, ongoing, and completed or terminated clinical studies. Researchers are increasingly using information from the database to assess research reporting practices, or to characterise the clinical research enterprise. Conducting valid analyses requires an understanding of both the capabilities and limitations of the database (that is, intrinsic factors) as well as reporting policies and other factors external to the database that influence the types of studies in ClinicalTrials.gov in a specified time. This article discusses 10 key issues that researchers need to consider when using the database to conduct research.