OBJECTIVE:
To investigate the credibility of authors’ claims of subgroup effects using a representative sample of recently published randomized controlled trials.

DESIGN:
Systematic review.

DATA SOURCE:
Core clinical journals, as defined by the National Library of Medicine, in Medline.

STUDY SELECTION:
Randomised controlled trials published in 2007. Using prespecified criteria, teams of trained reviewers independently judged whether authors claimed subgroup effects and the strength of their claims. Reviewers assessed each of these claims against 10 predefined criteria, developed through a search of existing criteria and a consensus process.

RESULTS:
Of 207 randomised controlled trials reporting subgroup analyses, 64 (31%) made claims for the primary outcome. Of those, 20 were strong claims and 28 claims of a likely effect. Authors included subgroup variables measured at baseline in 60 (94%) trials, used subgroup variable as a stratification factor at randomisation in 13 (20%), clearly prespecified their hypotheses in 26 (41%), correctly prespecified direction in 4 (6%), tested a small number of hypotheses in 28 (44%), carried out a test of interaction that proved statistically significant in 6 (9%), documented replication of a subgroup effect with previous related studies in 21 (33%), identified consistency of a subgroup effect across related outcomes in 19 (30%), and provided a compelling indirect evidence for the effect in 14 (22%). In the 19 trials making more than one claim, only one (5%) checked the independence of the interaction. Of the 64 claims, 54 (84%) met four or fewer of the 10 criteria. For strong claims, more than 50% failed each of the individual criteria, and only three (15%) met more than five criteria.

CONCLUSION:
Authors often claim subgroup effects in their trial report. However, the credibility of subgroup effects, even when claims are strong, is usually low. Users of the information should treat claims that fail to meet most criteria with scepticism. Trial researchers should report the conduct of subgroup analyses and provide sufficient evidence when claiming a subgroup effect or suggesting a possible effect.

PURPOSE:
To discuss the methodological considerations of a standard and applicable randomized clinical trial (RCT).
MATERIALS AND METHODS:
Using a predefined strategy, we conducted systematic computerized search of the MEDLINE (1966 to 2011) and EMBASE (1980 to 2011) databases to identify all English language educational articles discussing the RCT methodological aspects. Full text versions of identified studies were reviewed in blinded fashion for key methodological and statistical characteristics.
RESULTS:
Randomized clinical trials in surgery are the highest level of the primary research evidence in evidence-based medicine. There is increasing demand for implementation of RCTs in urological daily practice.
CONCLUSION:
Randomized clinical trials’ report should be absolutely clear, simple, and easy to understand with well-defined internal and external validity. Efforts should be made to design high quality RCTs in urology. There are substantial needs for urologists to their knowledge about RCT.

ABSTRACT:
To assess the factors associated with increased citation rates in the urological literature by reviewing articles published in the four major urological journals to help authors improve the impact of their work. A random sample of 200 original research articles published between January and June 2004 was analysed from The Journal of Urology, Urology, European Urology and BJU International. Study information was abstracted by two independent reviewers and citation counts within 4 years of publication were collected using Web of Science(TM) . Study characteristics and citation rates were analysed using median and interquartile ranges (IQRs), and logistic regression analysis was used to evaluate which factors predicted greater citation rates. The overall median number of citations per published article was 6.0 (IQR 3-12). After univariate analysis, we found that study design, study topic, continent of origin and sample size were associated with greater median citation rates. In a multivariate linear regression model, study design and study topic (oncology) predicted increased citation rates. Randomized controlled trials were cited a median of 13.5 times and were the strongest predictor of citation rates with an odds ratio of 115.5 (95% confidence interval 9.4-1419.6). Citation rates are associated with study design and study topic in the urological literature. Authors may improve the impact of their work by designing clinical studies with greater methodological safeguards against bias.

OBJECTIVE:
To examine the evidence on the benefits and harms of screening for prostate cancer.

DESIGN:
Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES:
Electronic databases including Medline, Embase, CENTRAL, abstract proceedings, and reference lists up to July 2010. Review methods Included studies were randomised controlled trials comparing screening by prostate specific antigen with or without digital rectal examination versus no screening. Data abstraction and assessment of methodological quality with the GRADE approach was assessed by two independent reviewers and verified by the primary investigator. Mantel-Haenszel and inverse variance estimates were calculated and pooled under a random effects model expressing data as relative risks and 95% confidence intervals.

RESULTS:
Six randomised controlled trials with a total of 387 286 participants that met inclusion criteria were analysed. Screening was associated with an increased probability of receiving a diagnosis of prostate cancer (relative risk 1.46, 95% confidence interval 1.21 to 1.77; P<0.001) and stage I prostate cancer (1.95, 1.22 to 3.13; P=0.005). There was no significant effect of screening on death from prostate cancer (0.88, 0.71 to 1.09; P=0.25) or overall mortality (0.99, 0.97 to 1.01; P=0.44). All trials had one or more substantial methodological limitations. None provided data on the effects of screening on participants' quality of life. Little information was provided about potential harms associated with screening.

CONCLUSIONS:
The existing evidence from randomised controlled trials does not support the routine use of screening for prostate cancer with prostate specific antigen with or without digital rectal examination.

PURPOSE
We assessed the quality of randomized, controlled trial reporting in abstracts from the annual meetings of the American Urological Association and determined whether the information provided is consistent with subsequent full text publications.

MATERIALS AND METHODS:
All randomized, controlled trials presented in abstract form at the 2002 and 2003 American Urological Association annual meetings were identified for review. A systematic PubMed search based on authorship and key words from the study title was done to identify all subsequent full text publications. A standardized evaluation form was developed based on the published literature, pilot tested in a separate sample and applied by 2 independent reviewers.

RESULTS:
A total of 126 randomized, controlled trials were identified for review, including 56 in 2002 and 70 in 2003. Approximately a third of the trials (43 or 34.1%) identified the study design as a randomized, controlled trial in the abstract title. The method of randomization, allocation concealment and blinding was reported in 0% (0), 0% (0) and 40.5% (51) of studies, respectively. Mean/median followup was provided in 27.0% of studies (34). Of 126 randomized, controlled trials presented in abstract form 62.7% (79) were subsequently published as full text articles. Study sample size and the number of randomized subjects differed in 24.1% and 28.9% of abstracts, respectively. From the small proportion of randomized, controlled trials (23 or 29.1%) that identified a single primary end point results differed in 9 of 23 (39.1%).

CONCLUSIONS:
Most abstracts fail to provide the necessary information to assess methodological quality. Organizers of urological meetings should consider implementing a more structured abstract format that requires authors to provide the necessary study details, thereby allowing urologists to critically appraise study validity.

OBJECTIVE:
To develop and apply a standardized evaluation form for assessing the methodological and reporting quality of observational studies of surgical interventions in urology.

METHODS:
An evaluation standard was developed using the Consolidated Standards for Reporting Trials statement and previously reported surgical reporting quality instruments. Consensus scoring among three reviewers was developed using two distinct sets of studies. All comparative observational trials involving therapeutic surgical procedures published in four major urological journals in 1995 and 2005 were randomly assigned to each reviewer. Categories of reporting adequacy included background, intervention, statistical analysis, results and discussion.

RESULTS:
Twenty-seven articles in 1995 and 62 in 2005 met the inclusion criteria; 90% of studies were retrospective. From 1995 to 2005, the overall reporting quality score increased by 3.9 points (95% confidence interval, CI, 2.7-5.9; P = 0.001), from a mean (sd) of 19.1 (3.9) to 23.0 (4.2) on a scale of 0-42. There were significant improvements in the reporting categories of study background (+0.7 points, 95% CI 0.1-1.3, P = 0.043, 0-8-point scale), intervention (+1.6 points, 0.8-2.3, P = 0.001, 0-9-point scale), and statistical analysis (+0.8 points, 0.2-1.4, P = 0.006, 0-9-point scale). There were smaller and statistically insignificant improvements for results (+0.5 points, -0.3 to 1.2, P = 0.217, 0-10-point scale) and discussion reporting (+0.4 points, -0.1 to 0.8, P = 0.106, 0-6-point scale).

CONCLUSIONS:
There have been minor improvements in the reporting of observational studies of surgical intervention between 1995 and 2005. However, reporting quality remains suboptimal. Clinical investigators, reviewers and journal editors should continue to strive for transparent reporting of the observational studies representing the bulk of the clinical evidence for urological procedures.

PURPOSE:
Increasingly there is a recognized need for the development of high quality, evidenced-based clinical guidelines to assist clinicians and patients in critically important treatment related decision making. We review the different approaches used by leading urological organizations to develop guidelines for the management of clinically localized prostate cancer and their specific recommendations for case management.

MATERIALS AND METHODS:
Guidelines for the management of localized prostate cancer developed by leading professional organizations were identified through the National Guidelines Clearinghouse™, PubMed®, cited references and personal communication with prostate cancer experts. A structured data abstraction was applied to assess how the guideline was developed, what type of professionals and stakeholders were involved in the development process, how the primary evidence was identified and graded, and what specific final recommendations were reported.

RESULTS:
Clinical practice guidelines on the management of clinically localized prostate cancer demonstrate major differences in their specific recommendations. Few recommendations are based on high level evidence, and there are considerable discrepancies among the systems used to grade the quality of the evidence and the strength of the recommendations.

CONCLUSIONS:
There appears to be a need to standardize the process used by leading urological organizations to develop clinical guidelines for the management of prostate cancer. A unified approach may offer considerable rewards in terms of efficiency, guideline credibility and optimal clinical decision making. Furthermore, increased efforts are indicated to promote studies that yield high quality evidence to guide the management of prostate cancer.

PURPOSE OF REVIEW:
Population-based investigations comprise a significant portion of the prostate cancer literature and contribute considerably to our knowledge of this disease. It is important to recognize, however, the inherent limitations of observational study designs. In this review, we will highlight important population-based studies in prostate cancer of high methodological quality using the framework of the recently published Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

RECENT FINDINGS:
Recent findings of population-based studies of prostate cancer have generated key advances in our understanding of prostate cancer outcomes and epidemiology, which are highlighted in this review. The STROBE criteria, which were developed to promote the transparent reporting of observational studies, provide an excellent framework to determine the validity of conclusions drawn from large population-based studies.

SUMMARY:
Population-based research is a powerful tool for understanding prostate cancer, but clinicians and investigators must interpret findings appropriately.

PURPOSE OF REVIEW:
Clinical practice guidelines are being increasingly recognized as critically important to an evidence-based practice. This article reviews the different approaches used by leading urological organizations to the development of prostate cancer guidelines. It further introduces the recommendations of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) working group as a unified approach to guideline development.

RECENT FINDINGS:
Clinical guidelines on the management of prostate cancer demonstrate major methodological differences. Most notably, considerable discrepancies with regards to the systems used to grade the quality of the evidence and the strength of recommendation exist. The GRADE approach classifies the quality of evidence as high, moderate, low or very low, according to factors that include study design and execution, and the consistency of the results. It subsequently classifies recommendations as strong or weak, according to the balance between benefits and downsides and the degree of confidence in estimates of the downsides.

SUMMARY:
There is an urgent need to standardize processes used to develop clinical guidelines for the management of patients with prostate cancer by leading urological organizations. Adoption of the GRADE approach would offer considerable rewards in terms of efficiency, guideline credibility and optimal clinical decision-making.

PURPOSE:
Knowledge of statistical terminology and the ability to critically interpret research findings are critical skills in the practice of evidence based medicine.

MATERIALS AND METHODS:
We provide a series of non-technical explanations of basic statistical concepts commonly encountered in the urological literature. In addition, we provide examples of common statistical pitfalls to increase awareness of limitations to consider when applying research findings to practice.

RESULTS:
Statistical goals encountered in the urological literature can be broadly categorized as summarizing outcome variables, comparing 2 or more groups, measuring association among variables or predicting 1 variable from another. Errors frequently include the use of an inappropriate test for the data type of interest or using statistical testing in a manner that increases the likelihood of false-positive results. Such errors pose a threat to the validity of research findings and they may undermine study conclusions.

CONCLUSIONS:
Editors and reviewers alike should strive for high standards of statistical analysis and reporting, and promote the publication of high quality evidence in the urological literature. The understanding of basic statistical concepts and the principles of the hypothesis testing framework is essential to the critical appraisal process and, therefore, important to all urologists. Statistical literacy should be fostered through educational materials and courses in the urological community.

PURPOSE:
Negative studies provide valuable information. However, conducting studies with inadequate power is unethical and an inefficient use of resources. The purpose of this study was to determine the prevalence of negative studies with inadequate power in urological literature.

MATERIALS AND METHODS:
The Journal of Urology, Urology and BJU International (formerly British Journal of Urology) from 1982 to 2002 were searched using the Ovid MEDLINE database. All clinical trials that contained the phrase "no difference" were identified. Data necessary for power calculation were extracted from applicable studies.

RESULTS:
Of the 417 articles identified in the MEDLINE search, 127 were negative studies that contained enough information to be analyzed. There were 70 (55%) articles from The Journal of Urology, 35 (28%) from BJU International and 22 (17%) from Urology. Of the studies that used continuous variables 65% had adequate power (greater than 80%) to detect a 50% difference between groups and 32% had adequate power to detect a 25% difference. Of the studies that used dichotomous variables only 33% had adequate power to detect a 50% difference between groups and 23% had adequate power to detect a 25% difference. Levels of adequate power in negative studies did not improve over time (p = 0.258).

CONCLUSIONS:
Many negative studies in urological literature are inconclusive because they lack adequate power to detect even large differences between groups. Inadequately powered studies often result in false conclusions that alter clinical behavior and deter further research. Therefore, it is imperative to consider power when interpreting literature. When designing future investigations power calculations should be performed to ensure sufficient patient recruitment to attain clinically meaningful results.

PURPOSE:
We provide a systematic assessment of the quality and accuracy of statistical reporting in the urology literature.

MATERIALS AND METHODS:
All original research publications with adult human subjects in a single issue (August 2004) of 4 leading urology journals were identified for formal review. A standardized evaluation form was developed in consultation with an experienced biostatistician and subsequently tested. Two independent reviewers with at least 1 year of formal training in research design and biostatistics who were blinded to authors and institutions reviewed each article. Discrepancies were settled by consensus and/or adjudication by the biostatistician.

RESULTS:
Of the 169 articles screened 97 met eligibility criteria for review. Cohort (43 of 97 or 44%) or cross-sectional (28 of 97 or 29%) designs comprised the majority of these studies. Only 10 randomized clinical trials (12.4%) were identified. Statistical tests were identified in 83 studies (93%). Overall 69 of 83 studies (71%) providing statistical comparisons had at least 1 statistical error, including using the wrong test for the data type in 28%, inappropriate use of a parametric test in 22% and failure to account for multiple comparisons in 65%. In studies applying multivariate analysis (29%) over fitting the model with too many variables was the most common statistical flaw (39%).

CONCLUSIONS: This formal review suggests that statistical methods are often used inappropriately in the urology literature, thereby potentially undermining the validity of study results and conclusions. An effort to raise the awareness of appropriate statistical techniques through postgraduate education appears indicated.

BACKGROUND:
Robot-assisted laparoscopic prostatectomy (RALP) is displacing radical retropubic prostatectomy as the gold standard surgical approach for clinically localised prostate cancer in the United States and is also being increasingly used in Europe and other parts of the world. This trend has occurred despite the paucity of high-quality evidence to support its relative superiority to more established treatment modalities.

OBJECTIVE:
We performed this study to critically assess the quality of published evidence on RALP to support this major shift in practice patterns.

DESIGN, SETTING, AND PARTICIPANTS:
We conducted a systematic review of the published literature through Medline and Embase (1966 to December 2008). All original research publications on RALP were included. Editorials, letters to the editor, and review articles were excluded.

MEASUREMENTS:
Two reviewers independently performed the data abstraction using a standardised form derived from the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria.

RESULTS AND LIMITATIONS:
Seventy-five original research publications met eligibility criteria. Fifty-five (73.3%) studies were published between 2005 and 2008, and 20 studies (26.7%) were published between 2001 and 2004. Approximately three-quarters of the studies were case series (74.7%), and only two (2.7%) randomised, controlled trials (RCT) were identified. Twelve authors co-wrote 72% (54 of 75) of the published studies. Reporting of STROBE criteria ranged from 100.0% (scientific rationale/background explained) to 1.3% (consideration of sample size), with no improvement over time. The study was limited to published literature in the English language.

CONCLUSIONS:
The published RALP literature is limited to observational studies of mostly low methodologic quality. Our findings draw into question to what extent valid conclusions about the relative superiority or equivalence of RALP to other surgical approaches can be drawn and whether published outcomes can be generalised to the broader community. There is an urgent need to raise the methodologic standards for clinical research on new urologic procedures and devices.