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Diagnostic accuracy studies are, like other clinical studies, at risk of bias due to shortcomings in design and conduct, and the results of a diagnostic accuracy study may not apply to other patient groups and settings. Readers of study reports need to be informed about study design and conduct, in sufficient detail to judge the trustworthiness and applicability of the study findings. The STARD statement (Standards for Reporting of Diagnostic Accuracy Studies) was developed to improve the completeness and transparency of reports of diagnostic accuracy studies. STARD contains a list of essential items that can be used as a checklist, by authors, reviewers and other readers, to ensure that a report of a diagnostic accuracy study contains the necessary information. STARD was recently updated. All updated STARD materials, including the checklist, are available at http://www.equator-network.org/reporting-guidelines/stard. Here, we present the STARD 2015 explanation and elaboration document. Through commented examples of appropriate reporting, we clarify the rationale for each of the 30 items on the STARD 2015 checklist, and describe what is expected from authors in developing sufficiently informative study reports.

Background Several hundred core outcome set (COS) projects have been systematically identified to date which, if adopted, ensure that researchers measure and report those outcomes that are most likely to be relevant to users of their research. The uptake of a COS by COS users will depend in part on the transparency and robustness of the methods used in the COS development study, which would be increased by the use of a standardised protocol. This article describes the development of the COS-STAP (Core Outcome Set-STAndardised Protocol Items) Statement for the content of a COS development study protocol. Methods The COS-STAP Statement was developed following the Enhancing the Quality and Transparency Of Health Research (EQUATOR) Network’s methodological framework for guideline development. This included an initial item generation stage, a two-round Delphi survey involving more than 150 participants representing three stakeholder groups (COS developers, journal editors and patient and public involvement researchers interested in COS development), followed by a consensus meeting with eight voting participants. Results The COS-STAP Statement consists of a checklist of 13 items considered essential documentation in a protocol, outlining the scope of the COS, stakeholder involvement, COS development plans and consensus processes. Conclusions Journal editors and peer reviewers can use the guidance to assess the completeness of a COS development study protocol submitted for publication. By providing guidance for key content, the COS-STAP Statement will enhance the drafting of high-quality protocols and determine how the COS development study will be carried out. Electronic supplementary material The online version of this article (10.1186/s13063-019-3230-x) contains supplementary material, which is available to authorized users.

Treatment of carbapenemase‐producing Enterobacterales bloodstream infections in solid organ transplant recipients is challenging. The objective of this study was to develop a specific score to predict mortality in solid organ transplant recipients with carbapenemase‐producing Enterobacterales bloodstream infections. A multinational, retrospective (2004‐2016) cohort study (INCREMENT‐SOT, ClinicalTrials.gov NCT02852902) was performed. The main outcome variable was 30‐day all‐cause mortality. The INCREMENT‐SOT‐CPE score was developed using logistic regression. The global cohort included 216 patients. The final logistic regression model included the following variables: INCREMENT‐CPE mortality score ≥8 (8 points), no source control (3 points), inappropriate empirical therapy (2 points), cytomegalovirus disease (7 points), lymphopenia (4 points), and the interaction between INCREMENT‐CPE score ≥8 and CMV disease (minus 7 points). This score showed an area under the receiver operating characteristic curve of 0.82 (95% confidence interval [CI] 0.76‐0.88) and classified patients into 3 strata: 0‐7 (low mortality), 8‐11 (high mortality), and 12‐17 (very‐high mortality). We performed a stratified analysis of the effect of monotherapy vs combination therapy among 165 patients who received appropriate therapy. Monotherapy was associated with higher mortality only in the very‐high (adjusted hazard ratio [HR] 2.82, 95% CI 1.13‐7.06, P = .03) and high (HR 9.93, 95% CI 2.08‐47.40, P = .004) mortality risk strata. A score‐based algorithm is provided for therapy guidance., This work was supported by Plan Nacional de I+D+i 2013‐2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases [REIPI RD16/0016/0008; RD16/0016/0001, RD16/0016/0002, RD16/0016/00010] ‐ co‐financed by European Development Regional Fund “A way to achieve Europe”, Operative program Intelligent Growth 2014‐2020; ESCMID Study Group for Infections in Compromised Hosts [ESGICH grant to JMA]; Sociedad Andaluza de Trasplante de Órgano Sólido [SATOT grant to LMM]; ESCMID Study Group for Bloodstream Infections and Sepsis (ESGBIS); and ESCMID Study Group for Antimicrobial Resistance Surveillance (ESGARS).

Treatment of carbapenemase-producing Enterobacterales bloodstream infections in solid organ transplant recipients is challenging. The objective of this study was to develop a specific score to predict mortality in solid organ transplant recipients with carbapenemase-producing Enterobacterales bloodstream infections. A multinational, retrospective (2004-2016) cohort study (INCREMENT-SOT, ClinicalTrials.gov NCT02852902) was performed. The main outcome variable was 30-day all-cause mortality. The INCREMENT-SOT-CPE score was developed using logistic regression. The global cohort included 216 patients. The final logistic regression model included the following variables: INCREMENT-CPE mortality score >= 8 (8 points), no source control (3 points), inappropriate empirical therapy (2 points), cytomegalovirus disease (7 points), lymphopenia (4 points), and the interaction between INCREMENT-CPE score >= 8 and CMV disease (minus 7 points). This score showed an area under the receiver operating characteristic curve of 0.82 (95% confidence interval [CI] 0.76-0.88) and classified patients into 3 strata: 0-7 (low mortality), 8-11 (high mortality), and 12-17 (very-high mortality). We performed a stratified analysis of the effect of monotherapy vs combination therapy among 165 patients who received appropriate therapy. Monotherapy was associated with higher mortality only in the very-high (adjusted hazard ratio [HR] 2.82, 95% CI 1.13-7.06, P = .03) and high (HR 9.93, 95% CI 2.08-47.40, P = .004) mortality risk strata. A score-based algorithm is provided for therapy guidance.

BACKGROUND Multiple arterial grafts may result in longer survival than single arterial grafts after coronary-artery bypass grafting (CABG) surgery. We evaluated the use of bilateral internal-thoracic-artery grafts for CABG. METHODS We randomly assigned patients scheduled for CABG to undergo bilateral or single internal-thoracic-artery grafting. Additional arterial or vein grafts were used as indicated. The primary outcome was death from any cause at 10 years. The composite of death from any cause, myocardial infarction, or stroke was a secondary outcome. RESULTS A total of 1548 patients were randomly assigned to undergo bilateral internal-thoracic-artery grafting (the bilateral-graft group) and 1554 to undergo single internal-thoracic-artery grafting (the single-graft group). In the bilateral-graft group, 13.9% of the patients received only a single internal-thoracic-artery graft, and in the single-graft group, 21.8% of the patients also received a radial-artery graft. Vital status was not known for 2.3% of the patients at 10 years. In the intention-to-treat analysis at 10 years, there were 315 deaths (20.3% of the patients) in the bilateral-graft group and 329 deaths (21.2%) in the single-graft group (hazard ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.12; P=0.62). Regarding the composite outcome of death, myocardial infarction, or stroke, there were 385 patients (24.9%) with an event in the bilateral-graft group and 425 patients (27.3%) with an event in the single-graft group (hazard ratio, 0.90; 95% CI, 0.79 to 1.03). CONCLUSIONS Among patients who were scheduled for CABG and had been randomly assigned to undergo bilateral or single internal-thoracic-artery grafting, there was no significant between-group difference in the rate of death from any cause at 10 years in the intention-to-treat analysis. Further studies are needed to determine whether multiple arterial grafts provide better outcomes than a single internal-thoracic-artery graft. (Funded by the British Heath Foundation and others; Current Controlled Trials number, ISRCTN46552265.)

Randomised controlled trials are considered to be the best method to assess comparative clinical efficacy and effectiveness, and can be a key source of data for estimating cost effectiveness. Central to the design of a randomised controlled trial is an a priori sample size calculation, which ensures that the study has a high probability of achieving its prespecified main objective. Beyond pure statistical or scientific concerns, it is ethically imperative that an appropriate number of study participants be recruited, to avoid imposing the burdens of a clinical trial on more patients than necessary. The scientific concern is satisfied and the ethical imperative is further addressed by the specification of a target difference between treatments that is considered realistic or important by one or more key stakeholder groups. The sample size calculation ensures that the trial will have the required statistical power to identify whether a difference of a particular magnitude exists. In this article, the key messages from the DELTA 2 guidance on determining the target difference and sample size calculation for a randomised controlled trial are presented. Recommendations for the subsequent reporting of the sample size calculation are also provided.

Systematic reviews of clinical trials aim to include all relevant studies conducted on a particular topic and to provide an unbiased summary of their results, producing the best evidence about the benefits and harms of medical treatments. Relevant studies, however, may not provide the results for all measured outcomes or may selectively report only some of the analyses undertaken, leading to unnecessary waste in the production and reporting of research, and potentially biasing the conclusions to systematic reviews. In this article, Kirkham and colleagues provide a methodological approach, with an example of how to identify missing outcome data and how to assess and adjust for outcome reporting bias in systematic reviews.

To combine individual participant data (IPD) from major international population-based cohorts, using harmonised OA data, to assess whether subjects with knee OA have an increased association with premature mortality.

Background: Randomised controlled trials (RCTs) are used to evaluate social and psychological interventions and inform policy decisions about them. Accurate, complete, and transparent reports of social and psychological intervention RCTs are essential for understanding their design, conduct, results, and the implications of the findings. However, the reporting of RCTs of social and psychological interventions remains suboptimal. The CONSORT Statement has improved the reporting of RCTs in biomedicine. A similar high-quality guideline is needed for the behavioural and social sciences. Our objective was to develop an official extension of the Consolidated Standards of Reporting Trials 2010 Statement (CONSORT 2010) for reporting RCTs of social and psychological interventions: CONSORT-SPI 2018. Methods: We followed best practices in developing the reporting guideline extension. First, we conducted a systematic review of existing reporting guidelines. We then conducted an online Delphi process including 384 international participants. In March 2014, we held a 3-day consensus meeting of 31 experts to determine the content of a checklist specifically targeting social and psychological intervention RCTs. Experts discussed previous research and methodological issues of particular relevance to social and psychological intervention RCTs. They then voted on proposed modifications or extensions of items from CONSORT 2010. Results: The CONSORT-SPI 2018 checklist extends 9 of the 25 items from CONSORT 2010: background and objectives, trial design, participants, interventions, statistical methods, participant flow, baseline data, outcomes and estimation, and funding. In addition, participants added a new item related to stakeholder involvement, and they modified aspects of the flow diagram related to participant recruitment and retention. Conclusions: Authors should use CONSORT-SPI 2018 to improve reporting of their social and psychological intervention RCTs. Journals should revise editorial policies and procedures to require use of reporting guidelines by authors and peer reviewers to produce manuscripts that allow readers to appraise study quality, evaluate the applicability of findings to their contexts, and replicate effective interventions.

Background Un case report è la descrizione narrativa di un caso clinico per scopi clinici, scientifici o formativi. Considerata l’assenza di specifiche linee guida per il reporting, i case report mancano del rigore necessario per guidare la pratica professionale o informare il disegno di studi clinici. Obiettivo Sviluppare, disseminare e implementare linee guida per il reporting dei casi clinici. Metodi è stato utilizzato un processo di consenso in 3 step: 1) pre-meeting: revisione della letteratura e interviste per definire gli item da includere nelle linee guida per il reporting; 2) meeting di consenso: stesura della bozza delle linee guida per il reporting; 3) post-meeting: feedback, revisione della bozza, test pilota e stesura della versione finale delle linee guida per il reporting. Risultatit Il processo di consenso, che ha coinvolto 27 partecipanti, ha portato alla stesura di una checklist di 13 item per il reporting dei casi clinici. Gli item principali di questa checklist sono: titolo, parole chiave, abstract, introduzione, informazioni sul paziente, dati clinici, timeline, valutazione diagnostica, interventi terapeutici, follow-up e outcome, discussione, punto di vista del paziente e consenso informato.] Conclusioni Auspichiamo che l’implementazione delle linee guida CARE (CAse REport) da parte delle riviste biomediche migliorerà completezza e trasparenza dei case report pubblicati, permettendone una aggregazione sistematica che potrà informare il disegno di studi clinici, fornire tempestive informazioni su efficacia ed effetti avversi e migliorare l’assistenza sanitaria.

Background Heart failure (HF) is a major public health problem with rising prevalence, especially in elderly. Survival rates for advanced HF patients are worse than those for breast or prostate cancer. Two decades of biomarker research highlighted the prognostic ability of certain markers, and informed the development of new or updated prognostic models. Despite numerous published models and NICE’s recognition of the need for prognosis information, no risk stratification models have been adequately established, nor has the quality of the models and the evidence they present being systematically brought together and tested. Objectives We hypothesise that HF–related biomarkers may offer an added value to the traditional prognostic factors for HF clinical outcomes, independent of other present co-morbidities. We aim to test this hypothesis through a systematic reviews series assessing the evidence of HF prognostic models using novel meta-analysis (MA) methodology and relevant critical appraisal tools. Methods We follow Cochrane methodology. Published search filters were combined for a sensitive literature search. Prognostic models including at least one HF-related biomarker were eligible. Independent pairs of co-authors carried out screening and data extraction. Based on the CHARMS and PROBAST checklists we considered model development studies with and without external validation in independent data, and model updating studies. MA will be carried out using recently published novel methodology. Results Searches yielded over 40,000 titles, highlighting the need for tighter, updated prognostic search filters. A pilot screening of 10% of these (ie 4000) returned only a 2% for full text screening, with an ultimate estimate of 150 included models for evaluation. Conclusions This is a complex time constrained project with potential to advise on future HF prognostic model design; contribute to improved HF clinical management; apply recently developed MA methodology for combining prognostic model data, and inform the project for developing Cochrane methodology standards of prognostic model reviews. Acknowledgements Project funded by the British Heart Foundation (grant no. PG/17/49/33099)

The Arabic‐speaking region is disproportionately affected by oral health conditions compared with industrialized nations. The World Health Organization recommends oral health integration into chronic disease programs in middle‐ to low‐income countries. This article evaluates availability of peer‐reviewed dental and oral health publications in the Arabic‐speaking region. Dental journals were identified through (i) PubMed NLM Catalog Journals; (ii) Scopus; (iii) Google Scholar; (iv) Science Direct; (v) the Index Medicus for the Eastern Mediterranean Regional Office; and (vi) Iraqi Academic Scientific Journals database. Each journal site was evaluated for aim/scope, publication period, activity status, format, and language. The search returned 28 dental and oral health professional journals that fit the study parameters; all were tabled and described by evaluation criteria. Language is a key element that emerged within the sample. The prevalence of online formats may inhibit community‐level practitioners from accessing regionally and culturally congruent dental research.

The objective of this analysis is to evaluate the necessity of large clinical trials using FLOW trial data. The FLOW pilot study and definitive trial were factorial trials evaluating the effect of different irrigation solutions and pressures on re-operation. To explore treatment effects over time, we analyzed data from the pilot and definitive trial in increments of 250 patients until the final sample size of 2447 patients was reached. At each increment we calculated the relative risk (RR) and associated 95% confidence interval (CI) for the treatment effect, and compared the results that would have been reported at the smaller enrolments with those seen in the final, adequately powered study. The pilot study analysis of 89 patients and initial incremental enrolments in the FLOW definitive trial favored low pressure compared to high pressure (RR: 1.50, 95% CI: 0.75–3.04; RR: 1.39, 95% CI: 0.60–3.23, respectively), which is in contradiction to the final enrolment, which found no difference between high and low pressure (RR: 1.04, 95% CI: 0.81–1.33). In the soap versus saline comparison, the FLOW pilot study suggested that re-operation rate was similar in both the soap and saline groups (RR: 0.98, 95% CI: 0.50–1.92), whereas the FLOW definitive trial found that the re-operation rate was higher in the soap treatment arm (RR: 1.28, 95% CI: 1.04–1.57). Our findings suggest that studies with smaller sample sizes would have led to erroneous conclusions in the management of open fracture wounds. NCT01069315 (FLOW Pilot Study) Date of Registration: February 17, 2010, NCT00788398 (FLOW Definitive Trial) Date of Registration: November 10, 2008.

Aim: To develop age-, sex-, and ethnic-Appropriate normative reference ranges for standard echocardiographic measurements of the left heart by combining echocardiographic measurements obtained from adult volunteers without clinical cardiovascular disease or significant cardiovascular risk factors, from multiple studies around the world.Methods and results: The Echocardiographic Normal Ranges Meta-Analysis of the Left heart (EchoNoRMAL) collaboration was established and population-based data sets of echocardiographic measurements combined to perform an individual person data meta-Analysis. Data from 43 studies were received, representing 51 222 subjects, of which 22 404 adults aged 18-80 years were without clinical cardiovascular or renal disease, hypertension or diabetes. Quantile regression or an appropriate parametric regression method will be used to derive reference values at the 5th and 95th centile of each measurement against age. Conclusion: This unique data set represents a large, multi-ethnic cohort of subjects resident in a wide range of countries. The resultant reference ranges will have wide applicability for normative data based on age, sex, and ethnicity. © The Author 2013.

Summary Background Charts of size at birth are used to assess the postnatal growth of preterm babies on the assumption that extrauterine growth should mimic that in the uterus. Methods The INTERGROWTH-21 st Project assessed fetal, newborn, and postnatal growth in eight geographically defined populations, in which maternal health care and nutritional needs were met. From these populations, the Fetal Growth Longitudinal Study selected low-risk women starting antenatal care before 14 weeks' gestation and monitored fetal growth by ultrasonography. All preterm births from this cohort were eligible for the Preterm Postnatal Follow-up Study, which included standardised anthropometric measurements, feeding practices based on breastfeeding, and data on morbidity, treatments, and development. To construct the preterm postnatal growth standards, we selected all live singletons born between 26 and before 37 weeks' gestation without congenital malformations, fetal growth restriction, or severe postnatal morbidity. We did analyses with second-degree fractional polynomial regression models in a multilevel framework accounting for repeated measures. Fetal and neonatal data were pooled from study sites and stratified by postmenstrual age. For neonates, boys and girls were assessed separately. Findings From 4607 women enrolled in the study, there were 224 preterm singleton births, of which 201 (90%) were enrolled in the Preterm Postnatal Follow-up Study. Variance component analysis showed that only 0·2% and 4·0% of the total variability in postnatal length and head circumference, respectively, could be attributed to between-site differences, justifying pooling the data from all study sites. Preterm growth patterns differed from those for babies in the INTERGROWTH-21 st Newborn Size Standards. They overlapped with the WHO Child Growth Standards for term babies by 64 weeks' postmenstrual age. Interpretation Our data have yielded standards for postnatal growth in preterm infants. These standards should be used for the assessment of preterm infants until 64 weeks' postmenstrual age, after which the WHO Child Growth Standards are appropriate. Size-at-birth charts should not be used to measure postnatal growth of preterm infants. Funding Bill & Melinda Gates Foundation.

Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field,1,2 and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research,3 and some health care journals are moving in this direction.4 As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews. Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in 4 leading medical journals in 1985 and 1986 and found that none met all 8 explicit scientific criteria, such as a quality assessment of included studies.5 In 1987, Sacks and colleagues6 evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in 6 domains. Reporting was generally poor; between 1 and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement.7 In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials.8 In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1). Box 1 Conceptual issues in the evolution from QUOROM to PRISMA

Background Compulsory submission of a checklist from the relevant reporting guideline is one of the most widespread journal requirements aiming to improve completeness of reporting. However, the current suboptimal levels of adherence to reporting guidelines observed in the literature may indicate that this journal policy is not having a significant effect. Findings We explored whether authors provided the appropriate CONSORT checklist extension for their study and whether there were inconsistencies between what authors claimed on the submitted checklist and what was actually reported in the published paper. We randomly selected 12 randomized trials from three journals that provide the originally submitted checklist and analyzed six core CONSORT items. Only one paper used the appropriate checklist extension and had no inconsistencies between what was claimed in the submitted checklist and what was reported in the published paper. Conclusion Journals should take further actions to take full advantage of the requirement for the submission of fulfilled CONSORT checklists, thus ensuring that these checklists reflect what is reported in the manuscript. Electronic supplementary material The online version of this article (10.1186/s13063-018-2475-0) contains supplementary material, which is available to authorized users.

Background: The long-term effects of off-pump coronary artery bypass continue to be controversial because some studies have reported increased adverse event rates with off-pump coronary artery bypass when compared with on-pump coronary artery bypass. The Arterial Revascularization Trial compared survival after bilateral versus single internal thoracic artery grafting. The choice of off-pump coronary artery bypass versus on-pump coronary artery bypass was based on the surgeon's discretion. We performed a post hoc analysis of the Arterial Revascularization Trial to compare 5-year outcomes with 2 strategies. Methods: Among 3102 patients enrolled in the Arterial Revascularization Trial, we selected 1260 patients who underwent off-pump coronary artery bypass versus 1700 patients who underwent on-pump coronary artery bypass with cardioplegic arrest for the present comparison. Primary outcomes were 5-year mortality and incidence of major cardiac and cerebrovascular events, including cardiovascular death, myocardial infarction, cerebrovascular accident, and revascularization after index procedure. Propensity score matching selected 1260 pairs for final comparison. Stratified Cox models were used for treatment effect estimate. Results: Hospital mortality was comparable between off-pump coronary artery bypass and on-pump coronary artery bypass groups (12 [1.0%] vs 15 [1.2%]; P = .7). Conversion rate to on-pump during off-pump coronary artery bypass was 29 of 1260 (2.3%). When compared with off-pump coronary artery bypass not converted, off-pump coronary artery bypass converted to on-pump presented a remarkably higher hospital mortality (10.3% vs 0.7%; P < .001). At 5 years, the mortality rate was 110 (8.9%) versus 102 (8.3%) in the off-pump coronary artery bypass and on-pump coronary artery bypass groups, respectively, with no significant difference (hazard ratio, 1.14; 95% confidence interval, 0.86-1.52; P = .35). Incidence of major cardiac and cerebrovascular events was 175 (14.3) versus 169 (13.8) in the off-pump coronary artery bypass and on-pump coronary artery bypass groups, respectively, with no significant difference (hazard ratio, 1.05; 95% confidence interval, 0.84-1.31; P = .65). Conclusions: The present post hoc Arterial Revascularization Trial analysis supports the hypothesis that both off-pump coronary artery bypass and on-pump coronary artery bypass are equally effective and safe.

Evidence shows the quality of reporting of randomised controlled trials (RCTs) is not optimal. The lack of transparent reporting impedes readers from judging the reliability and validity of trial findings, researchers from extracting information for systematic reviews and results in research waste. The Consolidated Standards of Reporting Trials (CONSORT) Statement was developed to improve the reporting of randomised controlled trials. Within-person trials are a particular type of trial for conditions that can affect two or more body sites, and are a useful and efficient tool because the comparisons between interventions are within-persons. Such trials are more commonly conducted in ophthalmology, dentistry and dermatology. The reporting of within-person trials has, however, been variable and incomplete, hindering their usefulness in clinical decision making and by future researchers. This document presents the CONSORT extension to within-person trials. It aims to facilitate the reporting of within-person trials. CONSORT within-person extends 16 items of the CONSORT 2010 checklist, and introduces a modified flowchart and baseline table to enhance transparency. Examples of good reporting and evidence-based rationale for CONSORT within-person checklist items are provided.

Well-written and transparent case reports (1) reveal early signals of potential benefits, harms, and information on the use of resources; (2) provide information for clinical research and feedback on clinical practice guidelines (CPGs), and (3) inform medical education. High-quality case reports are more likely when authors follow reporting guidelines. During 2011-2012 a group of clinicians, researchers, and journal editors developed recommendations for the accurate reporting of information in case reports that resulted in the CARE (CAse REport) Statement and Checklist. They were presented at the 2013 International Congress on Peer Review and Biomedical Publication, have been endorsed by multiple medical journals, and translated into nine languages. This explanation and elaboration document has the objective to increase the use and dissemination of the CARE Checklist in writing and publishing case reports. Each item from the CARE Checklist is explained and accompanied by published examples. The explanations and examples in this document are designed to support the writing of high-quality case reports by authors and their critical appraisal by editors, peer reviewers, and readers. This article and the 2013 CARE Statement and Checklist, available from the CARE website [www.carestatement. org] and the EQUATOR Network, [www.equator-network.org] are resources for improving the completeness and transparency of case reports.

Chinese herbal medicine (CHM) formulas are the major components of traditional Chinese medicine (TCM) interventions. The general reporting quality of randomized clinical trials (RCTs) of CHM formulas is disappointing although there are CONSORT (Consolidated Standards of Reporting Trials) Statement extensions for herbal medicinal interventions and acupuncture interventions. A group of TCM clinical experts, methodologists, epidemiologists and editors has developed CONSORT–CHM Formulas through a comprehensive process including publication of the CONSORT–CHM Formulas (Draft), solicitation of comments, revision and finalization. The CONSORT 2010 Statement was extended by introducing the idea of TCM Pattern and the features of CHM formulas. One new checklist sub-item, Keywords was added to facilitate the indexation and data searching. Seven of the 25 CONSORT checklist items, namely Title and Abstract, Background and Objectives, Participants, Interventions, Outcomes, Generalizability and Interpretation, are now elaborated upon and the explanation of Harms of CHM formulas is revised. Illustrative examples and explanations are also provided. We hope that CONSORT–CHM Formulas 2017 can improve the reporting quality of RCTs of CHM formulas.

Risk prediction models, developed to estimate the probability of an individual developing a particular outcome, are frequently published. Few are adequately validated resulting in a large number of prediction models not used in practice. Data are often measured with some degree of error. This error can influence the performance of a prediction model. The impact of either random or systematic error in a particular covariate, the covariate’s strength or the sample size at which this measurement error could become negligible on model performance is unknown. This simulation study investigates the impact of measurement error and its relationship to sample size and a covariate’s strength on calibration (i.e. how close observed and predicted probabilities are, and quantified by the calibration slope and Brier score), discrimination (i.e. how well the model differentiates between individuals with and without the outcome, and quantified by the c-index and D statistic), and explained variation (e.g. R2).

OBJECTIVE: Coronary artery bypass grafting (CABG) using bilateral internal mammary arteries (BIMA) may improve survival over CABG using single internal mammary arteries (SIMA), but may be surgically more complex (and therefore costly) and associated with impaired sternal wound healing. We report, for the first time, a detailed comparison of healthcare resource use and costs over 12 months, as part of the Arterial Revascularisation (ART) Trial. METHODS: 3102 patients in 28 hospitals in seven countries were randomised to CABG surgery using BIMA (n=1548) or SIMA (n=1554). Detailed resource use data were collected covering surgery, the initial hospital episode, and for 12 months post randomisation. Using UK unit costs, total costs were calculated and compared between trial arms and for subgroups. RESULTS: Patients randomised to BIMA spent 20 min longer in theatre (95% CI 15 to 25, pCONCLUSIONS: At 12 months from randomisation, mean costs were approximately 9% higher in BIMA than SIMA patients, primarily due to longer time in theatre and in-hospital stay, and slightly higher costs related to sternal wound problems during follow-up. Follow-up to the primary trial endpoint of 10 years will reveal whether longer-term differences emerge in graft patency or in overall survival. TRIAL REGISTRATION NUMBER: Controlled-trials.com (ISRCTN46552265).

[This corrects the article DOI: 10.1186/s41512-016-0001-y.].

This article contains a set of six invited commentaries written by leading scholars, expressing varied perspectives on the future of frontline research and on the frontline domain itself. The article accompanies the Journal of Service Research special issue on organizational frontlines. In their commentaries, the authors share insightful views on areas of personal interest ranging from employee emotion and customer relationship building to the effect of technology and its implementation at the organizational frontline. Included within each commentary are managerial insights and suggestions for needed research in the highlighted area.

Objective Accurate gestational‐age (GA) estimation, preferably by ultrasound measurement of fetal crown–rump length before 14 weeks' gestation, is an important component of high‐quality antenatal care. The objective of this study was to determine how GA can best be estimated by fetal ultrasound for women who present for the first time late in pregnancy with uncertain or unknown menstrual dates. Methods INTERGROWTH‐21st was a large, prospective, multicenter, population‐based project performed in eight geographically defined urban populations. One of its principal components, the Fetal Growth Longitudinal Study, aimed to develop international fetal growth standards. Each participant had their certain menstrual dates confirmed by first‐trimester ultrasound examination. Fetal head circumference (HC), biparietal diameter (BPD), occipitofrontal diameter (OFD), abdominal circumference (AC) and femur length (FL) were measured every 5 weeks from 14 weeks' gestation until delivery. For each participant, a single, randomly selected ultrasound examination was used to explore all candidate biometric variables and permutations to build models to predict GA. Regression equations were ranked based upon minimization of the mean prediction error, goodness of fit and model complexity. An automated machine learning algorithm, the Genetic Algorithm, was adapted to evaluate > 64 000 potential polynomial equations as predictors. Results Of the 4607 eligible women, 4321 (94%) had a pregnancy without major complications and delivered a live singleton without congenital malformations. After other exclusions (missing measurements in GA window and outliers), the final sample comprised 4229 women. Two skeletal measures, HC and FL, produced the best GA prediction, given by the equation loge(GA) = 0.03243 × (loge(HC))2 + 0.001644 × FL × loge(HC) + 3.813. When FL was not available, the best equation based on HC alone was loge(GA) = 0.05970 × (loge(HC))2 + 0.000000006409 × (HC)3 + 3.3258. The estimated uncertainty of GA prediction (half width 95% interval) was 6–7 days at 14 weeks' gestation, 12–14 days at 26 weeks' gestation and > 14 days in the third trimester. The addition of FL to the HC model led to improved prediction intervals compared with using HC alone, but no further improvement in prediction was afforded by adding AC, BPD or OFD. Equations that included other measurements (BPD, OFD and AC) did not perform better. Conclusions Among women initiating antenatal care late in pregnancy, a single set of ultrasound measurements combining HC and FL in the second trimester can be used to estimate GA with reasonable accuracy. We recommend this tool for underserved populations but considerable efforts should be implemented to improve early initiation of antenatal care worldwide. © 2016 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology., Linked Comment: Ultrasound Obstet Gynecol 2016; 48: 693–693

Objectives: We aimed to identify risk factors for antepartum stillbirth including fetal growth restriction, amongst women with well-dated pregnancies and access to antenatal care. Design: Population-based, prospective, observational study Setting: Eight international urban populations Population: Pregnant women and their babies enrolled in the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. Methods: Cox proportional Hazard models were used to compare risks amongst antepartum stillborn and liveborn babies. Main outcome measures: Antepartum stillbirth was defined as any fetal death after 16 weeks of gestation before the onset of labour. Results: Of 60 121 babies, 553 were stillborn (9.2 per 1000 births), of which 445 were antepartum deaths (7.4 per 1000 births). After adjustment for site, risk factors were low socio-economic status, Hazard ratio (HR): 1·6 (95% CI 1·2-2·1); single marital status, 2·0 (1·4-2·8); age  40 years, 2·2 (1·4-3·7); essential hypertension 4·0 (2·7-5·9); HIV/AIDS 4·3 (2·0-9·1); preeclampsia 1·6 (1·1-3·8), multiple pregnancy 3·3 (2.0-5·6) and antepartum haemorrhage 3.3 (2.5-4.5). Birth weight < 3rd centile was associated with antepartum stillbirth, 4.6 (3.4-6.2). The greatest risk was in babies not suspected to have been growth restricted antenatally, 5.0 (3.6-7.0). The population attributable risk of antepartum death associated with SGA diagnosed at birth was 11%. Conclusions: Antepartum stillbirth is a complex syndrome associated with several risk factors. Although small babies are at higher risk, current growth restriction detection strategies only modestly reduced the rate of stillbirth.

Objective Estimated fetal weight (EFW) and fetal biometry are complementary measures used to screen for fetal growth disturbances. Our aim was to provide international EFW standards to complement the INTERGROWTH‐21st Fetal Growth Standards that are available for use worldwide. Methods Women with an accurate gestational‐age assessment, who were enrolled in the prospective, international, multicenter, population‐based Fetal Growth Longitudinal Study (FGLS) and INTERBIO‐21st Fetal Study (FS), two components of the INTERGROWTH‐21st Project, had ultrasound scans every 5 weeks from 9–14 weeks' until 40 weeks' gestation. At each visit, measurements of fetal head circumference (HC), biparietal diameter, occipitofrontal diameter, abdominal circumference (AC) and femur length (FL) were obtained blindly by dedicated research sonographers using standardized methods and identical ultrasound machines. Birth weight was measured within 12 h of delivery by dedicated research anthropometrists using standardized methods and identical electronic scales. Live babies without any congenital abnormality, who were born within 14 days of the last ultrasound scan, were selected for inclusion. As most births occurred at around 40 weeks' gestation, we constructed a bootstrap model selection and estimation procedure based on resampling of the complete dataset under an approximately uniform distribution of birth weight, thus enriching the sample size at extremes of fetal sizes, to achieve consistent estimates across the full range of fetal weight. We constructed reference centiles using second‐degree fractional polynomial models. Results Of the overall population, 2404 babies were born within 14 days of the last ultrasound scan. Mean time between the last scan and birth was 7.7 (range, 0–14) days and was uniformly distributed. Birth weight was best estimated as a function of AC and HC (without FL) as log(EFW) = 5.084820 − 54.06633 × (AC/100)3 − 95.80076 × (AC/100)3 × log(AC/100) + 3.136370 × (HC/100), where EFW is in g and AC and HC are in cm. All other measures, gestational age, symphysis–fundus height, amniotic fluid indices and interactions between biometric measures and gestational age, were not retained in the selection process because they did not improve the prediction of EFW. Applying the formula to FGLS biometric data (n = 4231) enabled gestational age‐specific EFW tables to be constructed. At term, the EFW centiles matched those of the INTERGROWTH‐21st Newborn Size Standards but, at

Summary Research publication can both communicate and miscommunicate. Unless research is adequately reported, the time and resources invested in the conduct of research is wasted. Reporting guidelines such as CONSORT, STARD, PRISMA, and ARRIVE aim to improve the quality of research reports, but all are much less adopted and adhered to than they should be. Adequate reports of research should clearly describe which questions were addressed and why, what was done, what was shown, and what the findings mean. However, substantial failures occur in each of these elements. For example, studies of published trial reports showed that the poor description of interventions meant that 40–89% were non-replicable; comparisons of protocols with publications showed that most studies had at least one primary outcome changed, introduced, or omitted; and investigators of new trials rarely set their findings in the context of a systematic review, and cited a very small and biased selection of previous relevant trials. Although best documented in reports of controlled trials, inadequate reporting occurs in all types of studies—animal and other preclinical studies, diagnostic studies, epidemiological studies, clinical prediction research, surveys, and qualitative studies. In this report, and in the Series more generally, we point to a waste at all stages in medical research. Although a more nuanced understanding of the complex systems involved in the conduct, writing, and publication of research is desirable, some immediate action can be taken to improve the reporting of research. Evidence for some recommendations is clear: change the current system of research rewards and regulations to encourage better and more complete reporting, and fund the development and maintenance of infrastructure to support better reporting, linkage, and archiving of all elements of research. However, the high amount of waste also warrants future investment in the monitoring of and research into reporting of research, and active implementation of the findings to ensure that research reports better address the needs of the range of research users.

Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalizability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover 3 main study designs: cohort, case-control, and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors, to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. Eighteen items are common to all 3 study designs and 4 are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available at www.annals.org and on the Web sites of PLoS Medicine and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

I read Gepner and colleagues’ article with interest. In their most common form, randomized trials compare groups of persons receiving different interventions studied simultaneously. Each participant receives 1 intervention selected at random at enrollment. The probabilities of being allocated to each treatment are usually equal (for example, an allocation ratio of 1:1). That all participants have the same probability of receiving each treatment is implied. That principle is violated if the allocation ratio is changed (for example, from 1:1 to 1:2) partway through the trial. Although all participants are randomly assigned to 1 of the same set of possible treatments, bias can arise because the sets of participants recruited in the 2 phases of the trial may differ—for example, those recruited in the second part may be healthier than those in the first part. The correct approach is to separately analyze the data for each part of the trial and then combine the results

Objective(s) The question of whether skeletonized internal mammary artery (IMA) harvesting reduces the incidence of sternal wound complications in comparison to the pedicled technique, in the context of single or bilateral IMAs, remains controversial. We studied the impact IMA harvesting strategy on sternal wound complication in the Arterial Revascularization Trial (ART). Methods Patients enrolled in the ART (n=3102) were randomised to coronary artery bypass grafting with single or bilateral IMAs. Sternal wound complication rates were examined according to the harvesting technique that was documented in 2056 patients. The IMA harvesting technique, based on surgeon preference, resulted in 4 groups: pedicled single IMA (P-SIMA, n=607), pedicled bilateral IMA (P-BIMA, n=459), skeletonized single IMA (S-SIMA, n=512) and skeletonized bilateral IMA (S-BIMA, n=478). Propensity Scores weighting was used to estimate the impact of the harvesting technique on sternal wound complications. Results A total of 219 of 2056 patients (10.6%) experienced a sternal wound complication within 1 year from the index operation. Of those, only 25 (1.2%) patients required sternal wound reconstruction. P-BIMA (OR 1.80; 95%CI 1.23 to 2.63) but not S-BIMA (OR 1.00; 95%CI 0.65 to 1.53) or S-SIMA (OR 0.89; 95%CI 0.57-1.38) was associated with a significantly increased risk of any sternal wound complications compared to P-SIMA. Conclusions The present ART sub-study suggests that, with a skeletonization technique, the risk of sternal wound complication with BIMA grafting is similar to that after standard pedicled SIMA harvesting whilst skeletonized SIMA harvesting did not add any further benefit when compared to pedicled SIMA harvesting.

The choice of an adequate sample size for a Cox regression analysis is generally based on the rule of thumb derived from simulation studies (Peduzzi et al. (1995)) of a minimum of 10 events per variable (EPV). One simulation study suggested scenarios in which the 10 EPV rule can be relaxed (Vittinghoff and McCulloch (2007)). The effect of a range of binary predictors with varying prevalence, reflecting clinical practice, has not yet been fully investigated.We conducted an extended resampling study using a large general practice data set, comprising over 2 million anonymized patient records, to examine the EPV requirements for prediction models with low-prevalence binary predictors developed using Cox regression. The performance of the models was then evaluated using an independent external validation data set. We investigated both fully specified models and models derived using variable selection.Our results indicated that an EPV rule of thumb should be data-driven and that EPV > 10 generally eliminates bias in regression coefficients when many low-prevalence predictors are included in a Cox model.Higher EPV is needed when low-prevalence predictors are present in a model to eliminate bias in regression coefficients and improve predictive accuracy.

Background and study aims: Terminal digit preference bias for “pleasing” numbers has been described in many areas of medicine. The aim of this study was to determine whether endoscopists, radiologists, and pathologists exhibit such bias when measuring colorectal polyp diameters. Methods: Colorectal polyp diameters measured at endoscopy, computed tomographic colonography (CTC), and histopathology were collated from a colorectal cancer screening program and two parallel multicenter randomized trials. Smoothing models were fitted to the data to estimate the expected number of polyps at 1-mm increments, assuming no systematic measurement bias. The difference between the expected and observed numbers of polyps was calculated for each terminal digit using statistical modeling. The impact of measurement bias on per-patient detection rates of polyps ≥ 10 mm was estimated for each modality. Results: A total of 92 124 individual polyps were measured by endoscopy (91 670 screening and 454 from trials), 2385 polyps were measured by CTC (1664 screening, 721 trials), and 79 272 were measured by histopathology (78 783 screening, 489 trials). Clustering of polyp diameter measurements at 5-mm intervals was demonstrated for all modalities, both in the screening program and the trials. The statistical models estimated that per-patient detection rates of polyps ≥ 10 mm were over-inflated by 2.4 % for endoscopy, 3.1 % for CTC, and 3.3 % for histopathology in the screening program, with similar trends in the randomized trials. Conclusion: Endoscopists, radiologists, and pathologists all exhibit terminal digit preference when measuring colorectal polyps. This will bias trial data, referral rates for further testing, adenoma surveillance regimens, and comparisons between tests.

Objectives: The relationship between atrial fibrillation (AF) and the development of cardiovascular and renal disease is unclear. We aimed to quantify the associations between AF and cardiovascular disease, renal disease and death. Design: Systematic Review and Meta-analysis. Data Sources: We conducted a systematic search of MEDLINE and EMBASE. Eligibility Criteria: We included cohort studies examining the association of AF with cardiovascular disease, renal disease and death. Two reviewers independently extracted study characteristics and the relative risk of outcomes associated with AF: specifically, all-cause mortality, cardiovascular mortality, major cardiovascular events, any stroke, ischemic stroke, hemorrhagic stroke, ischemic heart disease, sudden cardiac death, congestive heart failure, chronic kidney disease and peripheral arterial disease. Estimates were pooled using inverse-variance weighted random effects meta-analysis. Results: One hundred and four eligible cohort studies involving 9,686,513 participants (587,867 with AF) were identified. AF was associated with an increased risk of all-cause mortality (relative risk 1.46; 95% confidence interval 1.39 to 1.54), cardiovascular mortality (2.03; 1.79 to 2.30), major cardiovascular events (1.96; 1.53 to 2.51), stroke (2.42; 2.17 to 2. 71), ischemic stroke (2.33; 1.84 to 2.94), ischemic heart disease (1.61; 1.38 to 1.87), sudden cardiac death (1.88; 1.36 to 2.60), heart failure (4.99; 3.04 to 8.22), chronic kidney disease (1.64; 1.41 to 1.91) and peripheral arterial disease (1.31; 1.19 to 1.45), but not hemorrhagic stroke (2.00; 0.67 to 5.96). Among the outcomes examined, the absolute risk increase for heart failure was the greatest. Associations of AF with included outcomes were broadly consistent across subgroups and in sensitivity analyses. Conclusions: AF is associated with an increased risk of death and an increased risk of cardiovascular and renal disease. Interventions aimed at reducing outcomes beyond stroke are warranted in patients with AF.

Objective: The aim of this study was to assess long-term effects for women following the use of magnesium sulphate for pre-eclampsia. Design: Assessment at 2-3 years after delivery for women recruited to the Magpie Trial (recruitment in 1998-2001, ISRCTN 86938761), which compared magnesium sulphate with placebo for pre-eclampsia. Setting: Follow up after discharge from hospital at 125 centres in 19 countries across five continents. Population: A total of 7927 women were randomised at the follow-up centres. Of these women, 2544 were not included for logistic reasons and 601 excluded (109 at a centre where

The validity and practical utility of observational medical research depends critically on good study design, excellent data quality, appropriate statistical methods and accurate interpretation of results. Statistical methodology has seen substantial development in recent times. Unfortunately, many of these methodological developments are ignored in practice. Consequently, design and analysis of observational studies often exhibit serious weaknesses. The lack of guidance on vital practical issues discourages many applied researchers from using more sophisticated and possibly more appropriate methods when analyzing observational studies. Furthermore, many analyses are conducted by researchers with a relatively weak statistical background and limited experience in using statistical methodology and software. Consequently, even 'standard' analyses reported in the medical literature are often flawed, casting doubt on their results and conclusions. An efficient way to help researchers to keep up with recent methodological developments is to develop guidance documents that are spread to the research community at large. These observations led to the initiation of the strengthening analytical thinking for observational studies (STRATOS) initiative, a large collaboration of experts in many different areas of biostatistical research. The objective of STRATOS is to provide accessible and accurate guidance in the design and analysis of observational studies. The guidance is intended for applied statisticians and other data analysts with varying levels of statistical education, experience and interests. In this article, we introduce the STRATOS initiative and its main aims, present the need for guidance documents and outline the planned approach and progress so far. We encourage other biostatisticians to become involved.

Objectives: against a backdrop of rising levels of obesity, we describe and estimate associations of body mass index (BMI), age and gender with time to revision for participants undergoing primary total hip (THR) or knee (TKR) replacement in the UK.Design: population-based cohort study.Setting: routinely collected primary care data from a representative sample of general practices, including linked data on all secondary care events.Participants: population-based cohort study of 63?162 patients with THR and 54?276 with TKR in the UK General Practice Research Database between 1988 and 2011.Primary and secondary outcomes: risk of THR and TKR revision associated with BMI, age and gender, after adjusting for the competing risk of death.Results: the 5-year cumulative incidence rate for THR was 2.2% for men and 1.8% for women (TKR 2.3% for men, 1.6% for women). The adjusted overall subhazard ratio (SHR) for patients with THR undergoing subsequent hip revision surgery, with a competing risk of death, were estimated at 1.020 (95% CI 1.009 to 1.032) per additional unit (kg/m2) of BMI, 1.23 (95% CI 1.10 to 1.38) for men compared with women and 0.970 (95% CI 0.967 to 0.973) per additional year of age. For patients with TKR, the equivalent estimates were 1.015 (95% CI 1.002 to 1.028) for BMI; 1.51 (95% CI 1.32 to 1.73) for gender and 0.957 (95% CI 0.951 to 0.962) for age. Morbidly obese patients with THR had a 65.5% increase (95% CI 15.4% to 137.3%, p=0.006) in the subhazard of revision versus the normal BMI group (18.5–25). The effect for TKR was smaller (a 43.9% increase) and weaker (95% CI 2.6% to 103.9%, p=0.040).Conclusions: BMI is estimated to have a small but statistically significant association with the risk of hip and knee revision, but absolute numbers are small. Further studies are needed in order to distinguish between effects for specific revision surgery indications