Evidence Based Medicine

Evidence Based Medicine

اسلاید 1: www.tabaye.ir

اسلاید 2: Evidence Based MedicineClista Clanton, MSLS, AHIP June 28 & 29, 2012

اسلاید 3: Today’s topicsWhat is EBM?Why is it important?Complementary/Alternative medicineDeveloping the “well built” clinical questionSearching for evidenceEvaluating the evidence

اسلاید 4: What is evidence based medicine (EBM)?“the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.” The integration of individual clinical expertise with the best available external clinical evidence from systematic research. Initially proposed by Dr. David Sackett and colleagues at McMasters University in Ontario, Canada.Sackett DL, et al. Evidence-Based Medicine: What it is and what it isn’t. BMJ 1996; 312:71-2.

اسلاید 5: Adapted from: Sackett D.L., Rosenberg M.C., Gray J.A., Haynes R.B., Richardson W.S. (1996). Evidence based medicine: what it is and what it isnt. BMJ, 312, 71-72.

اسلاید 6: Why is EBM important?New types of evidence are being generated which can create changes in the way patients are treatedAlthough evidence is needed on a daily basis, usually physicians don’t get it.How much is actually being applied to patient care?lack of time out-of-date textbooks, and the disorganization of the up-to-date journals6 Covell DG, Uman GC, Manning PR: Information needs in office practice: Are they being met? Ann Intern Med 1985;103:596-9.

اسلاید 7: Why is EBM important?Up-to-date knowledge and clinical performance can deteriorate with timeThere is a statistically and clinically significant negative correlation between a physician’s knowledge of up to date care and the years that have elapsed since graduation from medical school. Ramsey PG, Carline JD, Inui TS et al: Changes over time in the knowledge base of practicing internists. JAMA 1991;266:1103-7.Davis DA, Thompson MA, Oxman AD, Haynes RB: Changing physician performance. A systematic review of the effect of continuing medical education strategies. JAMA 1995;274:700-5. Traditional continuing medical education programs have not been shown to improve clinical performanceSystematic reviews of the relevant randomized trials have shown that traditional, instructional CME fails to modify clinical performance and is ineffective in improving the health outcomes of patients.

اسلاید 8: Why is EBM important?Knowledge translation – increasing the uptake of the best available evidence into practice – has always been a challengeScurvy: use of citrus was proven to prevent and cure scurvy in 1754, but it was almost 50 years after the data was published before lemon juice was added to British shipsAdditive to diet (n=2 in each groupObserved effectQuart of ciderMinor improvementUnspecified elixir t.d.sNo changeSeawaterNo changeGarlic, mustard and horseradishNo changeSpoonfuls of vinegarNo changeTwo oranges and a lemonDramatic recoveryTable 1. Lind’s study on scurvy:1747The James Lind Library. Available from http://www.jameslindlibrary.org/. Accessed 26 June 2008.

اسلاید 9: Puerperal fever mortality rates for the First and Second Clinic at the Vienna General Hospital 1841-1846. The top line is the First Clinic, bottom line Second Clinic.

اسلاید 10: Why is EBM important?PeriodCharacteristics of periodNo. deliveriesNo. maternal deathsMaternal deaths/1000 deliveries1784-1822No routine post-mortems71,395 89712.51823-1838Routine post-mortems65,0353,74557.61839-1847Clinic arrangements changed First clinic: doctors and students Second clinic: midwives 20,204 17,791 1,989 691 90.2 33.81848-1859Hand-washing introduced First clinic Second clinic 47,938 40,770 1,712 1,248 35.7 30.6Chloride of lime: In 1846 Ignatz Semmelweis attributed puerperal fever to an infection carried by obstetricians. Despite reducing maternal mortality from 18 to 1.2% by hand-washing in chloride of lime, his findings were rejected by the medical society of Vienna. It would take until the 1890’s before it was accepted that microorganisms can cause disease.Table 2. Mortality rates and characteristic of obstetrics clinics in Vienna 1784-1859

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اسلاید 12: EBM processes can help with dissemination and adoption

اسلاید 13: Complementary/Alternative MedicineComplementary and alternative medicine is a group of diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine.National Center for Complementary and Alternative Medicine. Understanding complementary and alternative medicine. Available at:http://nccam.nih.gov/health/.While some scientific evidence exists regarding some CAM therapies, for most there are key questions that are yet to be answered through well-designed scientific studies--such as:Are these therapies safe? Do these therapies work for the diseases or medical conditions for which they are used?

اسلاید 14: Are Complimentary and Alternative Medicine Interchangeable Terms?Complementary medicine is used together with conventional medicine. Example: Using aromatherapy to help lessen a patients discomfort following surgery.National Center for Complementary and Alternative Medicine. Understanding complementary and alternative medicine. Available at: http://nccam.nih.gov/health/.Alternative medicine is used in place of conventional medicine. Example: When Suzanne Somers rejected chemotherapy in favor of a drug called Iscador (uses extracts of Mistletoe) to treat her breast cancer.

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اسلاید 16: Family: Woman Died After Choosing Herbal Medicine Over Cancer SurgeryStudies estimate that 60 percent of cancer patients try unconventional remedies and about 40 percent take vitamin or dietary supplementsNone has turned out to be a cure, although some show promise for easing symptoms. Touch therapies, mind-body approaches and acupuncture may reduce stress and relieve pain, nausea, dry mouth and possibly hot flashes, and are recommended by many top cancer experts. A recent study found that ginger capsules eased nausea if started days before chemotherapy.One quarter of supplements tested by an independent company over the last decade have had some sort of problem. Some contained contaminants. Others had contents that did not match label claims. Some had ingredients that exceeded safe limits. Some contained real drugs masquerading as natural supplements.

اسلاید 17: $2.5 billion spent, no alternative cures found Big, government-funded studies show most work no better than placebosThe Associated Pressupdated 11:15 a.m. CT, Wed., June 10, 2009BETHESDA, Md. - Ten years ago the government set out to test herbal and other alternative health remedies to find the ones that work. After spending $2.5 billion, the disappointing answer seems to be that almost none of them do.Echinacea for colds. Ginkgo biloba for memory. Glucosamine and chondroitin for arthritis. Black cohosh for menopausal hot flashes. Saw palmetto for prostate problems. Shark cartilage for cancer. All proved no better than dummy pills in big studies funded by the National Center for Complementary and Alternative Medicine. The lone exception: ginger capsules may help chemotherapy nausea.As for therapies, acupuncture has been shown to help certain conditions, and yoga, massage, meditation and other relaxation methods may relieve symptoms like pain, anxiety and fatigue.

اسلاید 18: Major Types of Complementary and Alternative MedicineAlternative medicine systems: Built upon complete systems of theory and practice. Examples: homeopathic medicine, naturopathic medicine, traditional Chinese medicine, Ayurveda.National Center for Complementary and Alternative Medicine. Understanding complementary and alternative medicine. Available at: http://nccam.nih.gov/health/.Mind-body interventions: Uses a variety of techniques designed to enhance the minds capacity to affect bodily function and symptoms. Some techniques that were considered CAM in the past have become mainstream (patient support groups and cognitive-behavioral therapy). Other mind-body techniques are still considered CAM, including meditation, prayer, mental healing, and therapies that use creative outlets such as art, music, or dance.

اسلاید 19: Major Types of Complementary and Alternative Medicine cont.Biologically Based Therapies: Use substances found in nature (herbs, foods, and vitamins). Example: shark cartilage to treat cancer.National Center for Complementary and Alternative Medicine. Understanding complementary and alternative medicine. Available at: http://nccam.nih.gov/health/.Examples of dietary supplements that have been incorporated into mainstream medicine:Folic acid to prevent birth defects Regimen of vitamins and zinc to slow the progression age-related macular degeneration (AMD).

اسلاید 20: Major Types of Complementary and Alternative Medicine cont.Manipulative or Body-Based Methods: Based on manipulation and/or movement of one or more parts of the body. Examples: chiropractic or osteopathic manipulation, massage.National Center for Complementary and Alternative Medicine. Understanding complementary and alternative medicine. Available at: http://nccam.nih.gov/health/.Energy Therapies: Involve the use of energy fields.Biofield therapies: intended to affect energy fields that purportedly surround and penetrate the human body (the existence of such fields has not yet been scientifically proven). Examples: qi gong, Reiki, Therapeutic Touch. Bioelectromagnetic-based therapies: unconventional use of electromagnetic fields, such as pulsed fields, magnetic fields, or alternating-current or direct-current fields.

اسلاید 21: NCCAMNational Center for Complementary and Alternative MedicinePart of NIH, established in 1998Dedicated to exploring complementary and alternative healing practices in the context of rigorous science, training complementary and alternative medicine (CAM) researchers, and disseminating authoritative information to the public and professionals.NCCAM Web site (nccam.nih.gov): publications, information for researchers, frequently asked questions, and links to other CAM-related resources.

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اسلاید 32: What is EBM?“Evidenced-based medicine is the concept of formalizing the scientific approach to the practice of medicine for identification of “evidence” to support our clinical decisions. It requires an understanding of critical appraisal and the basic epidemiologic principles of study design, point estimates, relative risk, odds ratios, confidence intervals, bias, and confounding. By using this information, clinicians can categorize evidence, assess causality, and make evidence-based recommendations. Evidence-based medicine allows analysis of complicated material so that we can make the best possible clinical decisions for the populations we serve.”Williams JK. Understanding evidence-based medicine: a primer. Am J Obstet Gynecol 2001:185-275-278.

اسلاید 33: Developing the clinical questionStep 1: Formulate the clinical issue into a searchable, answerable question.Step 2: Distinguish what type of question you may have.BackgroundForegroundExperience with Condition

اسلاید 34: Background questionsBackground questions ask for general information about a condition or thing.A question root (who, what, when, etc) combined with a verb.Background questions are typically answered by textbooks. What microbial organisms can cause community-acquired pneumonia?

اسلاید 35: Foreground questionsForeground questions ask for specific knowledge about a specific patient with a specific condition.Foreground questions are typically answered by databases that access the research literatureIs St. John’s Wort effective in relieving the symptoms of post-partum depression?

اسلاید 36: Developing the questionForeground questions usually have four components.P = Patient populationI = InterventionC = ComparisonO = Outcome

اسلاید 37: Patient population/diseaseThe patient population or disease of interest - age - gender - ethnicity - with certain disorder (e.g., hepatitis)InterventionThe intervention or range of interventions of interest - Exposure to disease - Prognostic factor A - Risk behavior (e.g., smoking)ComparisonWhat you want to compare the intervention against - No disease - Placebo or no intervention/therapy - Prognostic factor B - Absence of risk factor (e.g., non-smoking)OutcomeOutcome of interest - Risk of disease - Accuracy of diagnosis - Rate of occurrence of adverse outcome (e.g., death)PICO: Components of an answerable, searchable questionMelnyk, B. M., & Fineout-Overholt, E. (2005). Evidence-based practice in nursing & healthcare : A guide to best practice. Philadelphia, PA: Lippincott Williams & Wilkins.

اسلاید 38: In patient with [Patient/ Problem]does[Intervention]or[Comparison, if any]affect[Outcome]In patients with chronic pain, does the use of progressive muscle relaxation lead to a lessening of pain? In patients with significant anterior or posterior vaginal wall prolapse, do vaginal cones help? In patients with moderate depression, is St. John’s Wort vs. traditional SSRI’s effective in relieving symptoms with fewer adverse effects?

اسلاید 39: Types of QuestionsDiagnosis: How to select a diagnostic test or how to interpret the results of a particular test. Prognosis: What is the patients likely course of disease, or how to screen for or reduce risk. Therapy: Which treatment is the most effective, or what is an effective treatment for a particular condition. Harm or Etiology: Are there harmful effects of a particular treatment, or how these harmful effects can be avoided. Prevention: How can the patients risk factors be adjusted to help reduce the risk of disease? Cost: Looks at cost effectiveness, cost/benefit analysis.

اسلاید 40: Question Templates for Asking PICO Questions Therapy In __________________, what is the effect of ____________________ on ______________________ compared with __________________? Etiology Are ______________ who have _________________ at ________________ risk for/of ____________________ compared with _____________________ with/without ______________________? Diagnosis or Diagnostic Test Are (Is) _________________________ more accurate in diagnosing ________________ compared with ________________? Prevention For _________________ does the use of _______________ reduce the future risk of ________________ compared with _________________? Prognosis Does _______________ influence _________________ in patients who have __________________? Melnyk, B. M., & Fineout-Overholt, E. (2005). Evidence-based practice in nursing & healthcare : A guide to best practice. Philadelphia, PA: Lippincott Williams & Wilkins.

اسلاید 41: Medical literaturePrimary – original researchExperimental (an intervention is made or variables are manipulated)Randomized Control TrialsControlled trialsObservational (no intervention or variables are manipulated)Cohort studiesCase-control studiesCase reportsSecondary – reviews of original researchMeta-analysisSystematic reviewsPractice guidelinesReviewsDecision analysisConsensus reportsEditorial, commentary

اسلاید 42: Case series/case reportsReports on treatment, etc. of individual patientsAnbar RD, Savedoff AD. Treatment of binge eating with automatic word processing and self-hypnosis: a case report. Am J Clin Hypn. 2005 Oct-2006 Jan;48(2-3):191-8. Binge eating frequently is related to emotional stress and mood problems. In this report, we describe a 16-year-old boy who utilized automatic word processing (AWP) and self-hypnosis techniques in treatment of his binge eating, and associated anxiety, insomnia, migraine headaches, nausea, and stomachaches. He was able to reduce his anxiety by gaining an understanding that it originated as a result of fear of failure. He developed a new cognitive strategy through AWP, after which his binge eating resolved and his other symptoms improved with the aid of self-hypnosis. Thus, AWP may have helped achieve resolution of his binge eating by uncovering the underlying psychological causes of his symptoms, and self-hypnosis may have given him a tool to implement a desired change in his behavior.

اسلاید 43: Case Control StudiesStudies in which patients who already have a specific condition are compared with people who do notRely on medical records and patient recall for data collection

اسلاید 44: Hepatitis C; a retrospective study, literature review, and naturopathic protocol. Milliman WB. Lamson DW. Brignall MS. Alternative Medicine Review. 5(4):355-71, 2000 Aug. The standard medical treatment of hepatitis C infection is only associated with sustained efficacy in a minority of patients. Therefore, the search for other treatments is of utmost importance. Several natural products and their derivatives have demonstrated benefit in the treatment of hepatitis C and other chronic liver conditions. Other herbal and nutritional supplements have mechanisms of action that make them likely to be of benefit. This article presents comprehensive protocol, including diet, lifestyle, and therapeutic interventions. The authors performed a retrospective review of 41 consecutive hepatitis C patients. Of the 14 patients with baseline and follow-up data who had not undergone interferon therapy, seven had a greater than 25-percent reduction in serum alanine aminotransferase (ALT) levels after at least one month on the protocol. For all patients reviewed, the average reduction in ALT was 35 U/L (p=0.026). These data appear to suggest that a conservative approach using diet and lifestyle modification, along with safe and indicated interventions, can be effective in the treatment of hepatitis C. Controlled trials with serial liver biopsy and viral load data are necessary to confirm these preliminary findings.

اسلاید 45: Cohort studiesFrom a large population, follows patients who have a specific condition or receive a particular treatment over time and compared with another group that has not been affected by the condition or treatment studies

اسلاید 46: Kristal AR, Littman AJ, Benitez D, White E. Yoga practice is associated with attenuated weight gain in healthy, middle-aged men and women. Altern Ther Health Med. 2005 Jul-Aug;11(4):28-33. BACKGROUND: Yoga is promoted or weight maintenance, but there is little evidence of its efficacy. OBJECTIVE: To examine whether yoga practice is associated with lower mean 10-year weight gain after age 45. PARTICIPANTS: Participants included 15,550 adults, aged 53 to 57 years, recruited to the Vitamin and Lifestyle (VITAL) cohort study between 2000 and 2002. MEASUREMENTS: Physical activity (including yoga) during the past 10 years, diet, height, and weight at recruitment and at ages 30 and 45. All measures were based on self-reporting, and past weight was retrospectively ascertained. METHODS: Multiple regression analyses were used to examined covariate-adjusted associations between yoga practice and weight change from age 45 to recruitment, and polychotomous logistic regression was used to examine associations of yoga practice with the relative odds of weight maintenance (within 5%) and weight loss (> 5%) compared to weight gain. RESULTS: Yoga practice for four or more years was associated with a 3.1-lb lower weight gain among normal weight (BMI < 25) participants [9.5 lbs versus 12.6 Ibs] and an 18.5-lb lower weight gain among overweight participants [-5.0 lbs versus 13.5 Ibs] (both P for trend <.001). Among overweight individuals, 4+ years of yoga practice was associated with a relative odds of 1.85 (95% confidence interval [CI] 0.63-5.42) for weight maintenance (within 5%) and 3.88 (95% Cl 1.30-9.88) for weight loss (> 5%) compared to weight gain (P for trend .026 and .003, respectively). CONCLUSIONS: Regular yoga practice was associated with attenuated weight gain, most strongly among individuals who were overweight. Although causal inference from this observational study is not possible, results are consistent with the hypothesis that regular yoga practice can benefit individuals who wish to maintain or lose weight.

اسلاید 47: Randomized controlled trialsStudy effect of therapy on real patientsInclude methodologies that reduce the potential for biasIntervention group vs control groupPatients assigned in randomized fashionBlinded or non-blinded studies

اسلاید 48: Harikumar R, Raj M, Paul A, Harish K, Kumar SK, Sandesh K, Asharaf S, Thomas V. Listening to music decreases need for sedative medication during colonoscopy: a randomized, controlled trial. Indian J Gastroenterol. 2006 Jan-Feb;25(1):3-5.BACKGROUND: Music played during endoscopic procedures may alleviate anxiety and improve patient acceptance of the procedure. A prospective randomized, controlled trial was undertaken to determine whether music decreases the requirement for midazolam during colonoscopy and makes the procedure more comfortable and acceptable. METHODS: Patients undergoing elective colonoscopy between October 2003 and February 2004 were randomized to either not listen to music (Group 1; n=40) or listen to music of their choice (Group 2; n=38) during the procedure. All patients received intravenous midazolam on demand in aliquots of 2 mg each. The dose of midazolam, duration of procedure, recovery time, pain and discomfort scores and willingness to undergo a repeat procedure using the same sedation protocol were compared. RESULTS: Patients in Group 2 received significantly less midazolam than those in Group 1 (p=0.007). The pain score was similar in the two groups, whereas discomfort score was lower in Group 2 (p=0.001). Patients in the two groups were equally likely to be willing for a repeat procedure. CONCLUSION: Listening to music during colonoscopy helps reduce the dose of sedative medications and decreases discomfort experienced during the procedure.

اسلاید 49: Systematic reviewExtensive literature search is conducted in systematic fashionOnly uses studies with sound methodologyStudies are collected, reviewed, assessed and the results summarized according to predetermined criteria of the review question

اسلاید 50: Jepson RG, Mihaljevic L, Craig J. Cranberries for preventing urinary tract infections. The Cochrane Database of Systematic Reviews 2004, Issue 2. Background: Cranberries (particularly in the form of cranberry juice) have been used widely for several decades for the prevention and treatment of urinary tract infections (UTIs). The aim of this review is to assess the effectiveness of cranberries in preventing such infections. Objectives: To assess the effectiveness of cranberry juice and other cranberry products in preventing UTIs in susceptible populations. Search strategy: Electronic databases and the Internet were searched using English and non English language terms; companies involved with the promotion and distribution of cranberry preparations were contacted; reference lists of review articles and relevant trials were searched…searched in February 2003. Selection criteria: All randomised or quasi randomised controlled trials of cranberry juice/products for the prevention of urinary tract infections in susceptible populations. Trials of men, women or children were included. Data collection and analysis: Two reviewers independently assessed and extracted information. Information was collected on methods, participants, interventions and outcomes (urinary tract infections (symptomatic and asymptomatic), side effects and adherence to therapy). RR were calculated where appropriate, otherwise a narrative synthesis was undertaken. Quality was assessed using the Cochrane criteria. Main results: Seven trials met the inclusion criteria (four cross-over, three parallel group). The effectiveness of cranberry juice (or cranberry-lingonberry juice) versus placebo juice or water was evaluated in six trials, and the effectiveness of cranberries tablets versus placebo was evaluated in two trials (one study evaluated both juice and tablets). In two good quality RCTs, cranberry products significantly reduced the incidence of UTIs at twelve months (RR 0.61 95% CI:0.40 to 0.91) compared with placebo/control in women. One trial gave 7.5 g cranberry concentrate daily (in 50 ml), the other gave 1:30 concentrate given either in 250 ml juice or in tablet form. There was no significant difference in the incidence of UTIs between cranberry juice versus cranberry capsules (RR 1.11 95% CI:0.49 to 2.50). Five trials were not included in the meta-analyses due to methodological flaws or lack of available data. However, only one reported a significant result for the outcome of symptomatic UTIs. Side effects were common in all trials, and dropouts/withdrawals in several of the trials were high. Authors conclusions: There is some evidence from two good quality RCTs that cranberry juice may decrease the number of symptomatic UTIs over a 12 month period in women. If it is effective for other groups such as children and elderly men and women is not clear. The large number of dropouts/withdrawals from some of the trials indicates that cranberry juice may not be acceptable over long periods of time. In addition it is not clear what is the optimum dosage or method of administration (e.g. juice or tablets). Further properly designed trials with relevant outcomes are needed.

اسلاید 51: Meta-analysisExamines a group of valid studies on a topic Combines results using accepted statistical methodology to reach a consensus on the overall results

اسلاید 52: Linde K, Berner M, Egger M, Mulrow C. St Johns wort for depression: meta-analysis of randomised controlled trials. Br J Psychiatry. 2005 Feb;186:99-107. BACKGROUND: Extracts of Hypericum perforatum (St Johns wort) are widely used to treat depression. Evidence for its efficacy has been criticised on methodological grounds. AIMS: To update evidence from randomised trials regarding the effectiveness of Hypericum extracts. METHODS: We performed a systematic review and meta-analysis of 37 double-blind randomised controlled trials that compared clinical effects of Hypericum monopreparation with either placebo or a standard antidepressant in adults with depressive disorders. RESULTS: Larger placebo-controlled trials restricted to patients with major depression showed only minor effects over placebo, while older and smaller trials not restricted to patients with major depression showed marked effects. Compared with standard antidepressants Hypericum extracts had similar effects. CONCLUSIONS: Current evidence regarding Hypericum extracts is inconsistent and confusing. In patients who meet criteria for major depression, several recent placebo-controlled trials suggest that Hypericum has minimal beneficial effects while other trials suggest that Hypericum and standard antidepressants have similar beneficial effects.

اسلاید 53: Levels of evidenceLevel I: obtained from at least one properly controlled randomized trial, considered the gold standard of evidence.Level II-1:derived from controlled trials without randomization. Level II-2: well-designed cohort or case-control studies. Level II-3: includes studies with external control groups or ecological studies. Level III evidence is derived from reports of expert committees, not because it is weaker than levels I or II, but because it is often difficult to ascertain the scientific origin of the committee opinion.

اسلاید 54: Evidence PyramidCase Series/Case ReportsCase Control StudiesCohort StudiesRandomized Controlled TrialSystematic ReviewMeta-analysisAnimal Research

اسلاید 55: Type of QuestionSuggested Best Type of StudyTherapyRCT > cohort > case control > case seriesDiagnosisProspective, blind comparison to gold standardEtiology / HarmRCT > cohort > case control > case seriesPrognosisCohort study > case control > case seriesPreventionRCT > cohort study > case control > case seriesClinical ExamProspective, blind comparison to gold standardCostEconomic analysisQuestions of therapy, etiology and prevention which can best be answered by RCT can also be answered by a meta-analysis or systematic review.Questions of therapy, etiology and prevention which can best be answered by RCT can also be answered by a meta-analysis or systematic review.

اسلاید 56: Question:In adult with acute maxillary sinusitis, does a 3-day course of trimethoprim-sulfamethoxazole yield the same cure rates as a 10-day course, with fewer adverse effects and costs?In patient with [Patient/ Problem]does[Intervention]or[Comparison, if any]affect[Outcome]Type of question:Type of study:TherapyRCT>cohort>case control> case series

اسلاید 57: A 42-year old woman presented at the emergency room of the hospital complaining of muscle pain and tiredness. She was found to have hyperventilation and weakness of four limbs, with muscle power of grade 5( )/5. All her symptoms gradually subsided over the next few hours. History revealed she was taking maqianzi, a herbal remedy, for neck pain. Could this herbal supplement have caused her problems? In patient with [Patient/ Problem]does[Intervention]or[Comparison, if any]affect[Outcome]Question:In an adult woman, does maqianzi cause muscle pain and tiredness?Type of question:Type of study:EtiologyRCT>cohort>case control> case series

اسلاید 58: You have heard that kidney yin deficiency is a valid tool to diagnose postmenopausal women with vasomotor symptoms. You need to find further information on this test.In patient with [Patient/ Problem]does[Intervention]or[Comparison, if any]affect[Outcome]Question:In a postmenopausal woman is kidney yin deficiency as effective as standard tools in diagnosis of vasomotor symptoms?Type of question:Type of study:DiagnosisProspective blind comparison to gold standard

اسلاید 59: SystemsComputerized decision supportSummariesDynamed, UptoDate, PIERClinical Evidence, EBM guidelinesSynopsesTRIP ACP Journal ClubSynthesesCochrane Systematic Reviews, DAREStudiesPubMed, CINAHL, Scopus Adapted from Haynes (2001)Haynes RB. Of studies, summaries, synopses, and systems: the “5S evolution of services for finding current best evidence. ACP Journal Club. 2001;134: A11–13.

اسلاید 60: Original StudiesIf an original study is your best option…….

اسلاید 61: IMRAD formatIntroduction: why the authors decided to conduct the research.Methods: how they conducted the research and analyzed their results.Results: what was found. AndDiscussion: what the authors think the results mean.

اسلاید 62: PP-ICONSProblemPatient or populationInterventionComparisonOutcomeNumber of subjectsStatisticsFlaherty, Robert J. A simple method for evaluating the clinical literature. Fam Prac Mgt, May 2004;47-52. Available online at http://www.aafp.org/fpm/20040500/47asim.html.

اسلاید 63: ScenarioYou just saw a nine-year old patient with common warts on her hands. She is an ideal candidate for cryotherapy. Her mother has heard about treating warts with duct tape and wants to know if you would recommend this treatment.

اسلاید 64: Clinical questionWhat is your clinical question? “In children with warts, is duct tape as effective as cryotherapy in eliminating the wart?PICO: Patient, Intervention/Comparison, Outcome

اسلاید 65: SearchAfter you have your clinical question, search the appropriate databases:Dynamed, PIER, UpToDate, Cochrane, Clinical EvidencePubMedFocht DR 3rd, Spicer C, Fairchok MP. The efficacy of duct tape vs cryotherapy in the treatment of verruca vulgaris (the common wart). Arch Pediatr Adolesc Med. 2002 Oct;156(10):971-4.

اسلاید 66: OBJECTIVE: To determine if application of duct tape is as effective as cryotherapy in the treatment of common warts. DESIGN: A prospective, randomized controlled trial with 2 treatment arms for warts in children. SETTING: The general pediatric and adolescent clinics at a military medical center. PATIENTS: A total of 61 patients (age range, 3-22 years) were enrolled in the study from October 31, 2000, to July 25, 2001; 51 patients completed the study and were available for analysis. INTERVENTION: Patients were randomized using computer-generated codes to receive either cryotherapy (liquid nitrogen applied to each wart for 10 seconds every 2-3 weeks) for a maximum of 6 treatments or duct tape occlusion (applied directly to the wart) for a maximum of 2 months. Patients had their warts measured at baseline and with return visits. MAIN OUTCOME MEASURE: Complete resolution of the wart being studied. RESULTS: Of the 51 patients completing the study, 26 (51%) were treated with duct tape, and 25 (49%) were treated with cryotherapy. Twenty-two patients (85%) in the duct tape arm vs 15 patients (60%) enrolled in the cryotherapy arm had complete resolution of their warts (P =.05 by chi(2) analysis). The majority of warts that responded to either therapy did so within the first month of treatment. CONCLUSION: Duct tape occlusion therapy was significantly more effective than cryotherapy for treatment of the common wart. Abstract

اسلاید 67: Problem (PP-ICONS)What is the clinical condition that was studied in the article?OBJECTIVE: To determine if application of duct tape is as effective as cryotherapy in the treatment of common warts. The problem studied should be sufficiently similar to your clinical problem, or the results will not be relevant.

اسلاید 68: Patient or Population (PP-ICONS)Is the study group similar to your patient or practice?SETTING: The general pediatric and adolescent clinics at a military medical center. PATIENTS: A total of 61 patients (age range, 3-22 years) If the patients in the study are not similar to your patient (older, sicker, different gender or more clinically complicated), the results may not be relevant.

اسلاید 69: Intervention (PP-ICONS)Is the intervention the same as what you are looking for? Could be a diagnostic test or a treatmentThe patient’s mother has heard about treating warts with duct tape and wants to know if you would recommend this treatment.

اسلاید 70: Comparison (PP-ICONS)The comparison is what the treatment is tested against. Could be a different diagnostic test, another therapy, placebo, or no treatment at all.INTERVENTION: Patients were randomized using computer-generated codes to receive either cryotherapy (liquid nitrogen applied to each wart for 10 seconds every 2-3 weeks) for a maximum of 6 treatments or duct tape occlusion (applied directly to the wart) for a maximum of 2 months.

اسلاید 71: Outcome (PP-ICONS)Disease-oriented outcomes (DOEs): usually reflect changes in physiologic parameters.It has long been assumed that improving the physiologic parameters of a disease will result in a better outcome, but this is not always true.Patient-oriented evidence that matters (POEMs): look at outcomes such as morbidity, mortality and cost. Therefore, DOEs are interesting but of questionable relevance, whereas POEMs are very interesting and very relevant.MAIN OUTCOME MEASURE: Complete resolution of the wart being studied.

اسلاید 72: Number (PP-ICONS)Number of subjects in the study is crucial in whether accurate statistics can be generated from the data.Too few patients may not be enough to show that a difference really exists between intervention and comparison groups (power of a study).Many studies contain <100 subjects, which is usually inadequate to provide reliable statistics.Good rule of thumb – 400 subjects needed.Krejcie RV, Morgan DW. Determining sample size for research activities. Educational and Psychological Measurements. 1970;30:607-610. 51 patients completed the study

اسلاید 73: Statistics (PP-ICONS)Relative risk reduction (RRR): the percent reduction in events in the treated group compared to the control group event rate.Not a good way to compare outcomesAmplifies small differences and makes insignificant findings appear significantDoesn’t reflect the baseline risk of the outcome eventCan make weak results look good, thereforePopular and will be reported in almost every journal articleIgnore – it can mislead youRRR would be (85 percent – 60 percent/60 percent x 100 = 42 percent I.e. 42 percent more effective than cryotherapy in treating warts

اسلاید 74: Statistics (PP-ICONS)Absolute risk reduction (ARR): the difference in the outcome event rate between the control group and the experimental group.A better statistic to evaluate outcome, as it does not amplify small differences, but shows the true difference between the experimental and control interventions.ARR for the wart study is the outcome event rate (complete resolution of warts) for duct tape (85 percent) minus the outcome event rate for cryotherapy (60 percent) = 25 percent

اسلاید 75: Statistics (PP-ICONS)Number needed to treat (NNT): number of patients who must be treated to prevent one adverse outcome OR the number of patients who must be treated for one patient to benefitSingle most clinically useful statisticEasy to calculate, simply the inverse of the ARR.For the wart study, the NNT is 1/25 percent = 1/0.25 = 44 patients need to be treated with duct tape for one to benefit more than if treated by cryotherapyThe lower the NNT, the better. For primary therapies, an NNT of 10 or less is good, with less than 5 being very good.For preventive interventions, the NNT will be higher. A NNT for prevention of less than 20 might be particularly good.

اسلاید 76: Intention to Treat AnalysisAttrition: Were patients lost to follow-up, and if so, why?Intention to treat: subjects are analyzed according to the categories into which they were originally randomized. Benefits of a treatment are more difficult to demonstrate with intention-to-treat analysis.Helps to mitigate differences by including subjects who are unlikely to have experienced benefit from the intervention.Six patients from cryotherapy group and 4 patients from the duct tape group were lost to follow-up (16% of patients).Worst case scenario: 6 cryotherapy patients had wart resolution and the 4 duct tape patients had residual wart. Wart resolution would then be: duct tape 78% and cryotherapy 68% (95% CI, -17 to 28) – therefore not a statistically significant difference between the two treatments.Christakis DA, Lehmann HP. Is duct tape occlusion therapy as effective as cryotherapy for the treatment of the common wart? Arch Pediatr Adolesc Med, Oct 2002; vol. 156; 975-977.

اسلاید 77: Best Type of Study for Your QuestionType of QuestionSuggested Best Type of StudyTherapyRCT > cohort > case control > case seriesDiagnosisProspective, blind comparison to gold standardEtiology / HarmRCT > cohort > case control > case seriesPrognosisCohort study > case control > case seriesPreventionRCT > cohort study > case control > case seriesClinical ExamProspective, blind comparison to gold standardCostEconomic analysisQuestions of therapy, etiology and prevention which can best be answered by RCT can also be answered by a meta-analysis or systematic review.Questions of therapy, etiology and prevention which can best be answered by RCT can also be answered by a meta-analysis or systematic review.

اسلاید 78: AssignmentIdentify a clinical problem with a patientFormulate a clinical question using PICOSearch the literature for appropriate article(s)Evaluate the article(s)Complete the online assignment within two weeks after date of lecture.http://biomedicallibrary.southalabama.edu/library/?q=ebmrotationsassignment