An e-mail survey identified unpublished studies for systematic reviews.


BACKGROUND AND OBJECTIVE:A large number of trials remain difficult to locate or unpublished for systematic reviews. The objective of this article was to determine the usefulness of making e-mail contact with authors of clinical trials and literature reviews found in MEDLINE to identify unpublished or difficult to locate Randomized Controlled Trials (RCTs). MATERIALS AND METHODS:A structured search for detecting RCTs in MEDLINE was made from January 1999 to June 2003; a questionnaire was sent to a random sample of 525 author's mails. Those RCTs obtained were sought in MEDLINE, EMBASE, the Cochrane Controlled Trials Register, LILACS, and ongoing registers. RESULTS:40 (7.6%) replies were received; 10 previously undescribed and unpublished RCTs and 21 unregistered ongoing RCTs were found. The most frequently given reasons for not publishing were: lack of time for finalizing the statistical analysis and preparing the manuscript, contractual obligations with the pharmaceutical industry, methodologic errors in designing, and editorial rejection. CONCLUSIONS:Using the e-mails of authors detected by the search in electronic databases could contribute toward detecting potentially relevant ongoing or unpublished RCTs enabling rapid, straightforward, low-cost systematic review; in addition, the results of this study support the need of universal registration of all studies at their inception.


J Clin Epidemiol


Reveiz L,Cardona AF,Ospina EG,de Agular S




Has Abstract


2006-07-01 00:00:00














  • A systematic review of core outcome set development studies demonstrates difficulties in defining unique outcomes.

    abstract:OBJECTIVES:Core outcome set (COS) development often begins with a systematic review to identify outcomes. Reviews frequently show heterogeneity in numbers of outcomes reported across trials. Contributing to this is a lack of a uniform definition for an outcome. This study proposes a first working definition for a uniqu...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Young AE,Brookes ST,Avery KNL,Davies A,Metcalfe C,Blazeby JM

    更新日期:2019-11-01 00:00:00

  • The importance of severity of illness adjustment in predicting adverse outcomes in the Medicare population.

    abstract::The importance of using risk-adjusted mortality rates to measure quality of care is well-established. However, mortality rates may be an insensitive measure of quality for surgical patients since death is a relatively rare outcome. This study used Medicare files to identify, through chart abstraction, clinical postope...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Rosen AK,Ash AS,McNiff KJ,Moskowitz MA

    更新日期:1995-05-01 00:00:00

  • Improving task comprehension in the measurement of health state preferences. A trial of informational cartoon figures and a paired-comparison task.

    abstract::Information concerning people's relative preferences for health care outcomes is usually obtained using questionnaires which ask subjects to imagine health states of various kinds. When using illness- or treatment-specific states, elaborate descriptions of patients' quality of life may adequately convey to the rater a...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Hadorn DC,Hays RD,Uebersax J,Hauber T

    更新日期:1992-03-01 00:00:00

  • Factors predicting stage of breast cancer at diagnosis in middle aged and elderly women: the role of living arrangements.

    abstract::We examined whether sociodemographic, health, and psychosocial factors predict stage at diagnosis in 444 women aged 55-84 with newly diagnosed, microscopically confirmed breast cancer. Stage was defined as local or advanced (regional or remote). One of the most interesting predictors of disease stage was living arrang...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Moritz DJ,Satariano WA

    更新日期:1993-05-01 00:00:00

  • Diagnostic certainty and potential for misclassification in exocrine pancreatic cancer. PANKRAS I Project Investigations.

    abstract::Whereas over the last decade epidemiologic studies on exocrine pancreatic cancer (EPC) continued to show a remarkable heterogeneity in diagnostic criteria applied to define caseness, the actual magnitude and consequences of misclassification remain largely unexplored. The objectives were: (1) to estimate the degree of...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Porta M,Malats N,Piñol JL,Rifà J,Andreu M,Real FX

    更新日期:1994-09-01 00:00:00

  • Reporting of trials presented in conference abstracts needs to be improved.

    abstract:OBJECTIVES:To assess how trial information reported in conference abstracts differs to their subsequent full publication. METHODS:Randomized trials reported at the American Society of Clinical Oncology conference (1992) were identified. CENTRAL and PubMed (December 2002) were searched to identify corresponding full pu...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Hopewell S,Clarke M,Askie L

    更新日期:2006-07-01 00:00:00

  • Three ways to quantify uncertainty in individually applied "minimally important change" values.

    abstract:OBJECTIVE:Determining "minimally important change" (MIC) facilitates the interpretation of change scores on multi-item instruments. This article focuses on how MIC values should be interpreted when applied to individual patients. STUDY DESIGN AND SETTING:The MIC value of a hypothetical questionnaire "Q" was determined...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: de Vet HC,Terluin B,Knol DL,Roorda LD,Mokkink LB,Ostelo RW,Hendriks EJ,Bouter LM,Terwee CB

    更新日期:2010-01-01 00:00:00

  • Gender differences in the reliability of reporting symptoms of angina pectoris.

    abstract::Numerous studies have shown that the symptoms of angina pectoris are more prevalent in women than men, than other manifestations of coronary heart disease, with the greatest discrepancies at younger ages. Variation in symptom reliability between genders could be a potential explanation for these differences. The Lipid...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Harris RB,Weissfeld LA

    更新日期:1991-01-01 00:00:00

  • Inadequate use and regulation of interventions against publication bias decreases their effectiveness: a systematic review.

    abstract:OBJECTIVES:To determine the effectiveness of interventions designed to prevent or reduce publication and related biases. STUDY DESIGN AND SETTING:We searched multiple databases and performed manual searches using terms related to publication bias and known interventions against publication bias. We dually reviewed cit...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Thaler K,Kien C,Nussbaumer B,Van Noord MG,Griebler U,Klerings I,Gartlehner G,UNCOVER Project Consortium.

    更新日期:2015-07-01 00:00:00

  • Synthesis of genetic association studies for pertinent gene-disease associations requires appropriate methodological and statistical approaches.

    abstract:OBJECTIVE:The aim of the study was to consider statistical and methodological issues affecting the results of meta-analysis of genetic association studies for pertinent gene-disease associations. Although the basic statistical issues for performing meta-analysis are well described in the literature, there are remaining...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Zintzaras E,Lau J

    更新日期:2008-07-01 00:00:00

  • A changing relationship between disability and survival in the elderly population: differences by age.

    abstract:BACKGROUND:Longitudinal studies estimating the association between disability and mortality in the elderly population have typically assumed disability constant through the follow-up study period. Current knowledge indicates that such assumptions may not be appropriate. Our purpose was to examine this association (disa...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Lamarca R,Ferrer M,Andersen PK,Liestol K,Keiding N,Alonso J

    更新日期:2003-12-01 00:00:00

  • Authors seldom report the most patient-important outcomes and absolute effect measures in systematic review abstracts.

    abstract:OBJECTIVES:Explicit reporting of absolute measures is important to ensure treatment effects are correctly interpreted. We examined the extent to which authors report absolute effects for patient-important outcomes in abstracts of systematic review (SR). STUDY DESIGN AND SETTING:We searched OVID MEDLINE and Cochrane Da...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Agarwal A,Johnston BC,Vernooij RW,Carrasco-Labra A,Brignardello-Petersen R,Neumann I,Akl EA,Sun X,Briel M,Busse JW,Ebrahim S,Granados CE,Iorio A,Irfan A,Martínez García L,Mustafa RA,Ramirez-Morera A,Selva A,Solà I,S

    更新日期:2017-01-01 00:00:00

  • The Internet is valid and reliable for child-report: an example using the Activities Scale for Kids (ASK) and the Pediatric Quality of Life Inventory (PedsQL).

    abstract:OBJECTIVE:This study tested the impact of web administration on well-established measures of children's physical function and quality of life. STUDY DESIGN AND SETTING:Participants were recruited from clinics at six hospitals. They completed the Activities Scale for Kids (ASK) and the Pediatric Quality of Life Invento...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,多中心研究


    authors: Young NL,Varni JW,Snider L,McCormick A,Sawatzky B,Scott M,King G,Hetherington R,Sears E,Nicholas D

    更新日期:2009-03-01 00:00:00

  • Oncology employees valued patient-oriented research over quality of work-life research: a qualitative study.

    abstract:OBJECTIVES:To assess the role of quality of work-life (QWL) research in a clinical research environment. STUDY DESIGN AND SETTING:A phenomenological qualitative research study was conducted. This research was conducted in a large Canadian ambulatory cancer treatment center that serves over 2.3 million people in Ontari...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Sale JE

    更新日期:2008-05-01 00:00:00

  • Assessment of functional status, low back disability, and use of diagnostic imaging in patients with low back pain and radiating leg pain.

    abstract::We analyzed data from outpatients with chronic low back pain (LBP) in the Veterans Health Study (n = 563) to examine the relationship between localized LBP intensity and radiating leg pain in assessing patient functional status, low back disability, and use of diagnostic imaging. Based on the localized LBP intensity, ...

    journal_title:Journal of clinical epidemiology

    pub_type: 临床试验,杂志文章,多中心研究


    authors: Ren XS,Selim AJ,Fincke G,Deyo RA,Linzer M,Lee A,Kazis L

    更新日期:1999-11-01 00:00:00

  • Comparing clinical information with claims data: some similarities and differences.

    abstract::How well can hospital discharge abstracts be used to estimate patient health status? This paper compares information on comorbidity obtained from hospital discharge abstracts for patients undergoing prostatectomy or cholecystectomy at a Winnipeg teaching hospital with clinical data on preoperative medical conditions p...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Roos LL,Sharp SM,Cohen MM

    更新日期:1991-01-01 00:00:00

  • Methodological review showed correct absolute effect size estimates for time-to-event outcomes in less than one-third of cancer-related systematic reviews.

    abstract:OBJECTIVES:To evaluate in how many cancer-related Cochrane reviews hazard ratio (HR)-based absolute effects in summary of findings (SoF) tables have been correctly calculated and reported. STUDY DESIGN AND SETTING:We identified all Cochrane cancer intervention reviews that reported an HR for at least one outcome and p...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Skoetz N,Goldkuhle M,Weigl A,Dwan K,Labonté V,Dahm P,Meerpohl JJ,Djulbegovic B,van Dalen EC

    更新日期:2019-04-01 00:00:00

  • Evaluation of the MOS SF-36 physical functioning scale (PF-10): I. Unidimensionality and reproducibility of the Rasch item scale.

    abstract::Indexes developed to measure physical functioning as an essential component of general health status are often based on sets of hierarchically-structured items intended to represent a broad underlying concept. Rasch Item Response Theory (IRT) provides a methodology to examine the hierarchical structure, unidimensional...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Haley SM,McHorney CA,Ware JE Jr

    更新日期:1994-06-01 00:00:00

  • The diagnostic value of the measurement of the ankle-brachial systolic pressure index in primary health care.

    abstract::We investigated the value of the ankle-brachial systolic pressure index (ABPI) as a test for the diagnosis of peripheral arterial occlusive disease (PAOD) in general practice. ABPI measurements on 231 legs of 117 subjects performed in three general practice centers (GPC) were compared with the diagnostic conclusions o...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,多中心研究


    authors: Stoffers HE,Kester AD,Kaiser V,Rinkens PE,Kitslaar PJ,Knottnerus JA

    更新日期:1996-12-01 00:00:00

  • Misclassification of exposure is high when interview data on drug use are used as a proxy measure of chronic drug use during follow-up.

    abstract:BACKGROUND AND OBJECTIVE:In many observational studies, the association between drugs and disease is analyzed with information from a baseline interview. We investigated the magnitude and direction of exposure misclassification by comparing interview data at baseline with prospectively gathered pharmacy data. METHODS:...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Beiderbeck AB,Sturkenboom MC,Coebergh JW,Leufkens HG,Stricker BH

    更新日期:2004-09-01 00:00:00

  • Among older adults, the responsiveness of self-rated health to changes in Charlson comorbidity was moderated by age and baseline comorbidity.

    abstract:OBJECTIVE:To examine the impact of changes in comorbidity--as measured by the Charlson comorbidity index--on self-rated health in a large sample of community-dwelling elderly over a 1-year period, and to examine the differential effects of changes in specific Charlson diagnostic categories. STUDY DESIGN AND SETTING:Lo...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Heller DA,Ahern FM,Pringle KE,Brown TV

    更新日期:2009-02-01 00:00:00

  • A case-control study on risk factors for Peyronie's disease.

    abstract::The aim of this study was to investigate the relationship between history of selected diseases, genital traumas, and Peyronie's disease. A hospital-based case-control study was conducted at the Andrologic and Surgical Outpatient Units of the Policlinico Gemelli, Rome, where 134 men with Peyronie's disease and 134 male...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Carrieri MP,Serraino D,Palmiotto F,Nucci G,Sasso F

    更新日期:1998-06-01 00:00:00

  • Translation and psychometric evaluation of a Chinese version of the SF-36 Health Survey in the United States.

    abstract::Outcome measures are rapidly becoming standard tools in the assessment of clinical effectiveness and in the measurement of health status in populations. In this article we document the development of a self-administered Chinese version of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and report t...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Ren XS,Amick B 3rd,Zhou L,Gandek B

    更新日期:1998-11-01 00:00:00

  • Nonrandomized studies using causal-modeling may give different answers than RCTs: a meta-epidemiological study.

    abstract:OBJECTIVES:To evaluate how estimated treatment effects agree between nonrandomized studies using causal modeling with marginal structural models (MSM-studies) and randomized trials (RCTs). STUDY DESIGN:Meta-epidemiological study. SETTING:MSM-studies providing effect estimates on any healthcare outcome of any treatmen...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Ewald H,Ioannidis JPA,Ladanie A,Mc Cord K,Bucher HC,Hemkens LG

    更新日期:2020-02-01 00:00:00

  • Time trends in the treatment of acute myocardial infarction in Switzerland from 1986 to 1993: do they reflect the advances in scientific evidence from clinical trials?

    abstract::Three acute coronary care surveys (1986, 1990, and 1993) were conducted in the Swiss region of Vaud-Fribourg on all men aged 25 to 64 years hospitalized for a definite myocardial infarction (218, 224, and 167 cases). Nearly all patients received anticoagulants and nitrates. The proportion of patients treated increased...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Bourquin MG,Wietlisbach V,Rickenbach M,Perret F,Paccaud F

    更新日期:1998-09-01 00:00:00

  • Congestive heart failure and outpatient risk of venous thromboembolism: a retrospective, case-control study.

    abstract::Although CHF has been considered a risk factor for venous thromboembolism, this has not been directly studied. We hypothesized that congestive heart failure would increase the risk of venous thromboembolism in an outpatient population, and that this risk would increase as patients' ventricular function worsened. We co...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Howell MD,Geraci JM,Knowlton AA

    更新日期:2001-08-01 00:00:00

  • Redundant meta-analyses are common in genetic epidemiology.

    abstract:OBJECTIVES:The massive growth in the publication of meta-analyses may cause redundancy and wasted efforts. We performed a metaepidemiologic study to evaluate the extent of potential redundancy in published meta-analyses in genetic epidemiology. STUDY DESIGN AND SETTING:Using a sample of 38 index meta-analyses of genet...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,评审


    authors: Sigurdson MK,Khoury MJ,Ioannidis JPA

    更新日期:2020-11-01 00:00:00

  • Factors associated with serum HCV RNA positivity in anti-HCV antibody positive intravenous drug users.

    abstract::Serum hepatitis C virus (HCV) RNA, HCV genotypes and liver function tests were evaluated in a series of 189 unselected, consecutive anti-HCV positive intravenous drug users (IVDUs). Serum HCV RNA was detected in 106/189 patients. Abnormal liver function tests were associated with alcohol abuse, but not with the presen...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Pirisi M,Toniutto P,Fabris C,Lombardelli T,Falleti E,Tisminetzky SG,Baralle F,Bartoli E

    更新日期:1998-05-01 00:00:00

  • An observational study showed that explaining randomization using gambling-related metaphors and computer-agency descriptions impeded randomized clinical trial recruitment.

    abstract:OBJECTIVES:To explore how the concept of randomization is described by clinicians and understood by patients in randomized controlled trials (RCTs) and how it contributes to patient understanding and recruitment. STUDY DESIGN AND SETTING:Qualitative analysis of 73 audio recordings of recruitment consultations from fiv...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章,多中心研究


    authors: Jepson M,Elliott D,Conefrey C,Wade J,Rooshenas L,Wilson C,Beard D,Blazeby JM,Birtle A,Halliday A,Stein R,Donovan JL,CSAW study group.,Chemorad study group.,POUT study group.,ACST-2 study group.,OPTIMA prelim study group.

    更新日期:2018-07-01 00:00:00

  • Developing a condition-specific measure of health for patients with dyspepsia and ulcer-related symptoms.

    abstract::A patient-administered instrument for dyspepsia and symptoms suggestive of duodenal or gastric ulcer, based on the type of questions asked when taking a patient's history, was developed and tested using the following steps: literature reviews, devising the questions, testing the responses to the questions using factor...

    journal_title:Journal of clinical epidemiology

    pub_type: 杂志文章


    authors: Garratt AM,Ruta DA,Russell I,Macleod K,Brunt P,McKinlay A,Mowat A,Sinclair T

    更新日期:1996-05-01 00:00:00