A Users’ Guide to the Urological Literature Series

 

A Users' Guide to the Urological Literature: Introducing a Series of Evidence Based Medicine Review Articles

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Dahm, P, & Preminger, GM. J Urol, 2007; 178(4):1149. No abstract.


Evidence Based Clinical Practice: A Primer for Urologists

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Scales, CD Jr, Preminger, GM, Keitz, SA & Dahm, P. J Urol, 2007; 178(3):775-82.

PURPOSE:
Evidence based clinical practice has been defined as the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients. It refers to a broad set of principles and methods intended to ensure that medical decisions, guidelines and health policy are based on well designed studies of therapeutic effectiveness and benefit.

MATERIALS AND METHODS:
We review the principles and practice of evidence based clinical practice using examples from the urology literature. We further provide a guide to currently available web based evidence based clinical practice resources and guidelines for urologists.

RESULTS:
Evidence based clinical practice integrates a hierarchy of evidence and patient values with practitioner judgment to guide decision making for the individual patient. Important steps in the evidence based clinical practice process include the formulation of an answerable question and a systematic search of the literature. In the absence of pre-appraised evidence or disease specific guidelines, the practice of evidence based clinical practice relies heavily on the evaluation of the primary literature by the individual urologist. Depending on the question domain (therapy/prevention, etiology/cause/harm, diagnosis or prognosis) and study design, a given study is critically appraised for validity, impact and applicability. Evidence is then integrated with clinical judgment, and patient circumstances and preferences. Finally, the practice of evidence based clinical practice includes a self-assessment of provider performance.

CONCLUSIONS:
Knowledge, practice and documentation of evidence based clinical practice are of increasing importance to every urologist. Urologists should embrace evidence based clinical practice principles by acquiring the necessary skills to critically appraise the literature for the best evidence applicable to patient care.

How to Perform a Literature Search

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Krupski, TL, Dahm, P, Fesperman, SF & Schardt, CM. J Urol, 2008; 179(4):1264-70.

PURPOSE:
Evidence based clinical practice seeks to integrate the current best evidence from clinical research with physician clinical expertise and patient individual preferences. We outline a stepwise approach to an effective and efficient search of electronic databases and introduce the reader to resources most relevant to the practicing urologist.

MATERIALS AND METHODS: The need for additional research evidence is introduced in the context of a urological clinical scenario. This information need is translated into a focused clinical question using the PICOT (population, intervention, comparison, outcome and type of study) format. This PICOT format provides key words for a literature search of pre-appraised evidence and original research studies that address the clinical scenario.

RESULTS:
Available online resources can be broadly categorized into databases that focus on primary research studies, ie randomized, controlled trials, cohort studies, case-control or case series, such as MEDLINE and those that focus on secondary research that provides synthesis or synopsis of primary studies. Examples of such sources of pre-appraised evidence that are becoming increasingly relevant to urologists include BMJ Clinical Evidence, ACP Journal Club, The Cochrane Library and the National Guideline Clearinghouse.

CONCLUSIONS:
The ability to search the medical literature in a time efficient manner represents an important part of an evidence based practice that is relevant to all urologists. The use of electronic databases of pre-appraised evidence can greatly expedite the search for high quality evidence, which is then integrated with urologist clinical skills and patient individual circumstances.

How to Use an Article about a Diagnostic Test

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Scales, CD Jr, Dahm, P, Sultan, S, Campbell-Scherer, D & Devereaux, PJ. J Urol, 2008; 180(2):469-76.

PURPOSE:
Urologists frequently confront diagnostic dilemmas, prompting them to select, perform and interpret additional diagnostic tests. Before applying a given diagnostic test the user should ascertain that the chosen test would indeed help decide whether the patient has a particular target condition. In this article in the Users' Guide to the Urological Literature series we illustrate the guiding principles of how to critically appraise a diagnostic test, interpret its results and apply its findings to the care of an individual patient.

MATERIALS AND METHODS:
The guiding principles of how to evaluate a diagnostic test are introduced in the setting of a clinical scenario. We propose a stepwise approach that addresses the question of whether the study results are likely to be valid, what the results are and whether these results would help urologists with the treatment of their individual patients.

RESULTS:
Some of the issues urologists should consider when assessing the validity of a diagnostic test study are how the authors assembled the study population, whether they used blinding to minimize bias and whether they used an appropriate reference standard in all patients to determine the presence or absence of the target disorder. Urologists should next evaluate the properties of the diagnostic test that indicate the direction and magnitude of change in the probability of disease for a particular test result. Finally, urologists should ask a series of questions to understand how the diagnostic test may impact the care of their patients.

CONCLUSIONS:
Application of the guides presented in this article will allow urologists to critically appraise studies of diagnostic tests. Determining the study validity, understanding the study results and assessing the applicability to patient care are 3 fundamental steps toward an evidence-based approach to choosing and interpreting diagnostic tests.

How to Use a Systematic Literature Review and Meta-Analysis

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Tseng, TY, Dahm, P, Poolman, RW, Preminger, GM, Canales, BJ & Montori, VM. J Urol, 2008; 180(4):1249-56.

PURPOSE:
This article introduces practicing urologists to the critical appraisal of systematic reviews and meta-analyses to guide their evidence-based clinical practice.

MATERIALS AND METHODS:
Using a urological clinical case scenario we introduce a 3-step process in evaluating systematic reviews and meta-analyses by considering 1) the validity of the review results, 2) what the results are, and 3) the extent to which the results can and should be applied to patient care.

RESULTS:
A systematic review seeks to synthesize the medical literature about a specific clinical question using explicit methods to perform a comprehensive literature search, identify and select eligible studies, critically appraise their methods, and judiciously summarize the results considering how they vary with study characteristics. When this summary involves statistical methods, ie a meta-analysis, reviewers can offer a pooled estimate that will have greater precision and will apply more broadly than the individual studies. The quality of the underlying studies, the consistency of results across studies and the precision of the pooled estimate can considerably affect the strength of inference from systematic reviews.

CONCLUSIONS:
Valid systematic reviews of high quality studies can increase the confidence with which urologists and patients make evidence-based decisions. Thus, urologists need to recognize the inherent limitations, understand the results and apply them judiciously to patient care.

How to Use an Article about Therapy

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Bajammal, S, Dahm, P, Scarpero, HM, Orovan, W & Bhandari, M. J Urol, 2008; 180(5):1904-11.

PURPOSE:
Most surgical interventions have inherent benefits and associated risks. Before implementing a new therapy we should ascertain the benefits and risks of the therapy and assure ourselves that the resources consumed in the intervention will not be exorbitant.

MATERIALS AND METHODS:
We suggest a 3-step approach to using an article from the urological literature to guide patient care. We recommend asking whether the study can provide valid results, reviewing the results and considering how the results can be applied to patient care.

RESULTS:
Key methodological characteristics that have an impact on the validity of a surgical trial include randomization, allocation concealment, stratification, blinding, completeness of follow up and intent to treat analysis. To the extent that the quality is poor inferences from this study are weakened. However, if its quality is acceptable, one must determine the range within which the true treatment effect lies (95% CI). One must then consider whether this result can be generalized to a patient and whether the investigators have provided information about all clinically important outcomes. It is then necessary to compare the relative benefits of the intervention with its risks. If one perceives that the benefits outweigh the risks, the intervention may be of use to the patient.

CONCLUSIONS:
Given the time constraints of busy urological practices and training programs, applying this analysis to every relevant article would be challenging. However, the basics of this process are essentially what we all do hundreds of times each week when treating patients. Making this process explicit with guidelines to assess the strength of the available evidence will serve to improve patient care. It will also allow us to defend therapeutic interventions based on available evidence and not on anecdote.

How to Use a Clinical Practice Guideline

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Dahm, P, Yeung, LL, Gallucci, M, Simone, G & Schünemann, HJ. J Urol, 2009; 181(2):472-9.

PURPOSE:
Leading organizations increasingly recognize clinical practice guidelines as an important approach in promoting an evidence-based clinical practice of urology. In light of their considerable clinical, economic and medicolegal impact, guideline users should be confident that the guidelines were rigorously developed and address relevant patient questions. In this article we outline a practical approach for critically appraising a clinical practice guideline.

MATERIALS AND METHODS:
We outline a 3-step approach to the assessment of a clinical practice guideline that answers the questions of whether the recommendations are valid, what the recommendations are and whether they will help in the treatment of an individual patient.

RESULTS:
To determine the adequacy of a clinical practice guideline, urologists should carefully review the rigor of the development process and its content. Important questions that relate to the validity of a guideline are whether, for specific questions, all important management options and outcomes were considered, and whether there was an explicit and sensible process to identify, select and combine all relevant evidence. Clinical practice guidelines should formally grade the quality of the available evidence for a given clinical question and outline a formal process of how the recommendations were derived. Value judgments made in the guideline development process about the relative importance of the potential benefits and harms of a given health care intervention should be made transparent to the reader. The recommendations made should be practical and should address important clinical issues. Furthermore, their strength should be graded to reflect the underlying uncertainty about the evidence and the values applied in the guideline development process.

CONCLUSIONS:
The systematic approach presented in this article will allow urologists to critically appraise clinical practice guidelines. Determining the validity of the recommendations, understanding the recommendations and assessing their applicability to patients are 3 fundamental steps toward an evidence-based approach to using clinical practice guidelines.

Understanding Results

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Breau, RH, Dahm, P, Fergusson, DA & Hatala, R. J Urol, 2009; 181(3):985-92

PURPOSE:
Properly conducted clinical trials provide essential evidence about the benefits and harms of a therapeutic intervention. To ensure accurate interpretation of study findings urologists should understand measures of effect and their precision. In this segment of the Users' Guide to the Urological Literature series we provide guidance on how measures of effect and precision should be interpreted and used in the evidence-based practice of urology.

MATERIALS AND METHODS:
Using an example from the urology literature we define commonly used measures of effect and describe how these statistics can be readily generated from the results of a clinical trial. We also highlight the importance of confidence interval interpretations when critically appraising study findings.

RESULTS:
The effect of an intervention can be described in absolute or relative terms. Risk of an event, risk difference and number needed to treat are easy to interpret, and allow the patient and urologist to assess the impact of an intervention in absolute terms. Relative measures of effect (relative risk, relative risk reduction) also characterize the treatment effect and can be applied to patients with varying baseline risk. The degree of precision within which the study estimated the actual effect size may be ascertained from the associated confidence interval. Confidence intervals are also useful when interpreting the benefit and harm of an experimental intervention and, therefore, are preferred compared to p values.

CONCLUSIONS:
Urologists do not need to rely on author interpretations of the effectiveness or harmfulness of a given intervention alone, but may interpret the result of the study themselves. An understanding of measures of effect size and precision is important to the interpretation of the urological literature and facilitates evidence-based clinical practice.

How to Use an Article about Prognosis

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Dahm P, Gilbert SM, Zlotecki RA, Guyatt GH. J Urol. 2010;183(4):1303-8.

PURPOSE:
This article in the Users' Guide to the Urological Literature series examines studies that provide information about prognosis for evidence-based clinical practice.

MATERIALS AND METHODS:
Studies of prognosis are introduced to the reader in the context of a clinical scenario that raises questions about the expected outcome for a patient. Critical appraisal of prognostic studies addresses the 3 questions. 1) Are the results valid? 2) What are the results? 3) Can I apply the results to the care of my patients?

RESULTS:
To assess the validity of a cohort study that addresses a question of prognosis, the reader should first ask whether the sample of patients under investigation were representative and sufficiently homogeneous with respect to prognostic risk. Investigators should measure all plausible determinants of outcome (prognostic or risk factors) and present results for all subgroups in which the prognosis differs substantially. The reader should ask whether followup was sufficiently complete, and whether investigators used objective, unbiased and patient relevant outcomes. The results should address the likelihood of the outcomes of interest and the precision of the estimates. Finally the reader should ask how similar the study patients and treatment are to his/her patients, and whether followup was sufficiently long.

CONCLUSIONS:
Questions of prognosis have an important role in the practice of urology and are usually best answered by nonrandomized, observational studies. Urologists should critically appraise these studies for validity, impact and applicability before using the results to guide patient care.

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