Douglas Altman

Douglas Altman
University of Oxford | OX · Centre for Statistics in Medicine

About

1,025
Publications
411,919
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624,254
Citations
Additional affiliations
January 2010 - December 2011
January 2010 - present
January 2009 - present
University Medical Center Utrecht

Publications

Publications (1,025)
Article
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Background: From 2005 to 2010, we conducted 2 randomized studies on a journal (Medicina Clínica), where we took manuscripts received for publication and randomly assigned them to either the standard editorial process or to additional processes. Both studies were based on the use of methodological reviewers and reporting guidelines (RG). Those inte...
Article
Background From 2005 to 2010, we conducted 2 randomized studies on a journal (Medicina Clínica), where we took manuscripts received for publication and randomly assigned them to either the standard editorial process or to additional processes. Both studies were based on the use of methodological reviewers and reporting guidelines (RG). Those interv...
Article
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Background To our knowledge, no publication providing overarching guidance on the conduct of systematic reviews of observational studies of etiology exists. Methods and findings Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology (COSMOS-E) provides guidance on all steps in systematic reviews of observational studi...
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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 use...
Article
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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...
Article
Prognostic factors are associated with the risk of future health outcomes in individuals with a particular health condition or some clinical start point (eg, a particular diagnosis). Research to identify genuine prognostic factors is important because these factors can help improve risk stratification, treatment, and lifestyle decisions, and the de...
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Most studies aiming to construct reference or standard charts use a cross‐sectional design, collecting one measurement per participant. Reference or standard charts can also be constructed using a longitudinal design, collecting multiple measurements per participant. The choice of appropriate statistical methodology is important as inaccurate centi...
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This paper discusses the features of study design and methodological considerations for constructing reference centile charts for attained size, growth, and velocity charts with a focus on human growth charts used during pregnancy. Recent systematic reviews of pregnancy dating, fetal size, and newborn size charts showed that many studies aimed at c...
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Background: Cancer prognostic biomarkers have shown disappointing clinical applicability. The objective of this study was to classify and estimate how study results are overinterpreted and misreported in prognostic factor studies in oncology. Methods: This systematic review focused on 17 oncology journals with an impact factor above 7. PubMed wa...
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Background: As complete reporting is essential to judge the validity and applicability of multivariable prediction models, a guideline for the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) was introduced. We assessed the completeness of reporting of prediction model studies published just...
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Binary logistic regression is one of the most frequently applied statistical approaches for developing clinical prediction models. Developers of such models often rely on an Events Per Variable criterion (EPV), notably EPV ≥10, to determine the minimal sample size required and the maximum number of candidate predictors that can be examined. We pres...
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Purpose: To assess the adherence of stroke randomised controlled trials to Consolidated Standards Of Reporting Trials reporting guidelines and investigate the factors that are associated with completeness of reporting. Method: We took a random sample from the Cochrane Stroke Group's Trial Register of transient ischaemic attack or stroke randomis...
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The Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK) were developed to address widespread deficiencies in the reporting of such studies. The REMARK checklist consists of 20 items to report for published tumor marker prognostic studies. A detailed paper was published explaining the rationale behind checklist items, providing po...
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In 2010, the NC3Rs published the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines to improve the reporting of animal research. Despite considerable levels of support from the scientific community, the impact on the quality of reporting in animal research publications has been limited. This position paper highlights the strategy...
Data
Table S1. Baseline Characteristics of Patients in the Aprotinin and No‐Aprotinin Groups in the Original Sample Table S2. Hospital Outcomes in the Original Sample Table S3. Five‐Year Outcomes in the Original Sample Figure S1. Rate of missing data for all variables analyzed.
Article
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Background: There is still uncertainty about the safety of aprotinin for coronary artery bypass graft surgery. The ART (Arterial Revascularization Trial) was designed to compare survival after bilateral versus single internal thoracic artery grafting. Many of the ART patients (≈30%) received perioperative aprotinin. We investigated the association...
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Many reports of health research omit important information needed to assess their methodological robustness and clinical relevance. Without clear and complete reporting, it is not possible to identify flaws or biases, reproduce successful interventions, or use the findings in systematic reviews or meta-analyses. The EQUATOR Network (http://www.equa...
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Background Core outcome sets (COS) comprise a minimum set of outcomes that should be measured and reported in all trials for a specific health condition. The COMET (Core Outcome Measures in Effectiveness Trials) Initiative maintains an up to date, publicly accessible online database of published and ongoing COS. An annual systematic review update i...
Data
PRISMA checklist for content of a systematic review. (DOC)
Data
Table of reports included in updated review (n = 18). (DOCX)
Article
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To review the effects of bilateral versus single internal mammary artery grafts for coronary bypass grafting.
Article
Background The arterial revascularization trial (ART) has been designed to answer the question whether the use of bilateral internal thoracic arteries (BITA) can improve 10-year outcomes when compared to single internal thoracic artery (SITA). In the ART, a significant proportion of patients initially allocated to BITA received other conduit strate...
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Methods to assess risk of bias in a way that is reliable, reproducible and transparent to readers, have evolved over time. Viswanathan et al. recently provided updated recommendations for assessing risk of bias in systematic reviews of health care interventions. We comment on their recommendations, and discuss new tools in development that we, as c...
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Background Selective reporting of outcomes in clinical trials is a serious problem. We aimed to investigate the influence of the peer review process within biomedical journals on reporting of primary outcome(s) and statistical analyses within reports of randomised trials. Methods Each month, PubMed (May 2014 to April 2015) was searched to identify...
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Importance While guidance on statistical principles for clinical trials exists, there is an absence of guidance covering the required content of statistical analysis plans (SAPs) to support transparency and reproducibility. Objective To develop recommendations for a minimum set of items that should be addressed in SAPs for clinical trials, develop...
Article
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Objectives: To investigate the application and interpretation of statistical analyses in a cross-section of systematic reviews (SRs) of therapeutic interventions, without restriction by journal, clinical condition, or specialty. Study design and setting: We evaluated a random sample of SRs assembled previously, which were indexed in MEDLINE® dur...
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Background: The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization r...
Article
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 thor...
Article
Full-text available
Background: The use of core outcome sets (COS) ensures that researchers measure and report those outcomes that are most likely to be relevant to users of their research. Several hundred COS projects have been systematically identified to date, but there has been no formal quality assessment of these studies. The Core Outcome Set-STAndards for Deve...
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Background: Retrospective studies provide conflicting interpretations of the effect of inherited genetic factors on breast cancer prognosis. The primary aim of this study was to determine the impact of a germline BRCA1/2 mutation on outcomes in young onset breast cancer. Method: Patients were recruited from 127 UK oncology centres and were eligibl...
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Objectives: To evaluate how often reproducible research practices, which allow others to recreate the findings of studies, given the original data, are used in systematic reviews (SRs) of biomedical research. Study design and setting: We evaluated a random sample of SRs indexed in MEDLINE® during February 2014, which focused on a therapeutic int...
Article
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Introduction There is evidence that the use of some reporting guidelines, such as the Consolidated Standards for Reporting Trials, is associated with improved completeness of reporting in health research. However, the current levels of adherence to reporting guidelines are suboptimal. Over the last few years, several actions aiming to improve compl...
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Aims: Recent guidelines recommend that patients with heart failure and left ventricular ejection fraction (LVEF) 40-49% should be managed similar to LVEF ≥ 50%. We investigated the effect of beta-blockers according to LVEF in double-blind, randomized, placebo-controlled trials. Methods and results: Individual patient data meta-analysis of 11 tri...
Article
The importance of adequate intervention descriptions in minimising research waste and improving research usability and reproducibility has gained attention in the past few years. Nearly all focus to date has been on intervention reporting in randomised trials. Yet clinicians are encouraged to use systematic reviews, whenever available, rather than...
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Background Guidelines for assessing methodological and reporting quality of systematic reviews (SRs) were developed to contribute to implementing evidence-based health care and the reduction of research waste. As SRs assessing a cohort of SRs is becoming more prevalent in the literature and with the increased uptake of SR evidence for decision-maki...
Article
Objectives: To assess a comprehensive package of ultrasound quality control in a large multicentre study of fetal growth - the Fetal Growth Longitudinal Study of the INTERGROWTH-21(st) Project. Methods: We performed quality control (QC) measures on 20,313 ultrasound scan images taken prospectively from 4,321 fetuses at 14-41 weeks' gestation in...
Article
Incomplete and inadequate reporting is an avoidable waste that reduces the usefulness of research. The CONSORT (Consolidated Standards of Reporting Trials) Statement is an evidence-based reporting guideline that aims to improve research transparency and reduce waste. In 2008, the CONSORT Group developed an extension to the original statement that a...
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The selection of appropriate outcomes is crucial when designing clinical trials in order to compare the effects of different interventions directly. For the findings to influence policy and practice, the outcomes need to be relevant and important to key stakeholders including patients and the public, health care professionals and others making deci...
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Background The methodological quality and completeness of reporting of the systematic reviews (SRs) is fundamental to optimal implementation of evidence-based health care and the reduction of research waste. Methods exist to appraise SRs yet little is known about how they are used in SRs or where there are potential gaps in research best-practice g...
Article
Objective To examine how poor reporting and inadequate methods for key methodological features in randomised controlled trials (RCTs) have changed over the past three decades. Design Mapping of trials included in Cochrane reviews. Data sources Data from RCTs included in all Cochrane reviews published between March 2011 and September 2014 reportin...
Article
Introduction Evidence-based medicine works best if the evidence is reported well. Past studies have shown reporting quality to be lacking in the field of surgery. Reporting guidelines are an important tool for authors to optimize the reporting of their research. The objective of this study was to analyse the frequency and strength of recommendation...
Article
e14023 Background: To generate empirical evidence, classify and estimate the frequency of distorted presentation and overinterpretation of results in prognostic factor (PF) studies in oncology. Methods: We selected 17 oncology journals with an impact factor of 7 or more. PubMed was searched to identify primary clinical studies evaluating one or mor...
Article
Missteps in the design and conduct of phase 1 trials have resulted in morbidity and mortality.¹,2 Empirical evidence to improve regulatory review of phase 1 trials is lacking. We studied the characteristics of phase 1 trials, frequency of harms, and dissemination of results.